Roundup Reference — Roundup 2.3.0 documentation
Description: Reference for the internals of Roundup. Includes background information for cookbook and how-to examples. Reference for the design and internals needed to understand and extend the examples to meet new needs.

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# Roundup Reference

Welcome

This document used to be part of the customisation document. The customisation document was getting large and unwieldy. It was a combination of examples and internal information that made finding information difficult. We often had questions on the mailing list that were well answered in the customisation document, but finding the info was difficult.

The documentation is slowly being reorganized using the Diataxis framework. Help with the reorganization is welcome.

This document provides background for the tutorials or how-tos in the customisation document.

- Trackers in a Nutshell
- Tracker Configuration
  - Extending the configuration file
- Tracker Schema
  - What you can/can’t do to the schema
  - The `schema.py` and `initial_data.py` modules
  - The “classic” schema
  - Classes and Properties - creating a new information store
  - Examples of adding to your schema
  - Schema Integrity
- Detectors - adding behaviour to your tracker
  - Detector API
  - Additional Detectors Ready For Use
  - Auditor or Reactor?
  - Vetoing creation of or changes to items
  - Generating email from Roundup
- Extensions - adding capabilities to your tracker
- interfaces.py - hooking into the core of Roundup
- Database Content
- Security / Access Controls
  - Automatic Permission Checks
  - New User Roles
  - Changing Access Controls
- Web Interface
  - Repercussions of changing the tracker schema
  - How requests are processed
  - Roundup URL design
  - Determining web context
  - The “home” Context
  - Serving static content
  - Performing actions in web requests
  - Protecting users from web application attacks
  - Special form variables
  - Default templates
  - Implementing Modal Editing Using @template
  - How the templates work
  - Information available to templates
  - Displaying Properties
  - Index Views
  - Searching Views
  - Item Views
  - Defining new web actions
  - 8-bit character set support in Web interface
- Debugging Trackers

## Trackers in a Nutshell

Trackers have the following structure:

Tracker File | Description
--- | ---
config.ini | Holds the basic tracker configuration
schema.py | Holds the tracker schema
initial_data.py | Holds any data to be entered into the database when the tracker is initialised (optional)
interfaces.py | Allows modifying the core of Roundup (optional)
db/ | Holds the tracker’s database
db/files/ | Holds the tracker’s upload files and messages
db/backend_name | Names the database back-end for the tracker (obsolete). Use the `backend` setting in the `[rdbms]` section of `config.ini` instead.
detectors/ | Auditors and reactors for this tracker
extensions/ | Additional actions and templating utilities
html/ | Web interface templates, images and style sheets
lib/ | optional common imports for detectors and extensions

## Tracker Configuration

The `config.ini` located in your tracker home contains the basic configuration for the web and e-mail components of Roundup’s interfaces.

Changes to the data captured by your tracker is controlled by the tracker schema. Some configuration is also performed using permissions - see the security / access controls section. For example, to allow users to automatically register through the email interface, you must grant the “Anonymous” Role the “Email Access” Permission.

The following is taken from the Python Library Reference (July 18, 2018) section “ConfigParser – Configuration file parser”:

> The configuration file consists of sections, led by a [section] header and followed by name: value entries, with continuations in the style of RFC 822 (see section 3.1.1, “LONG HEADER FIELDS”); name=value is also accepted. Note that leading whitespace is removed from values. The optional values can contain format strings which refer to other values in the same section, or values in a special DEFAULT section. Additional defaults can be provided on initialization and retrieval. Lines beginning with ‘#’ or ‘;’ are ignored and may be used to provide comments.

> For example:

>     [My Section]
>     foodir = %(dir)s/whatever
>     dir = frob

> would resolve the “%(dir)s” to the value of “dir” (“frob” in this case) resulting in “foodir” being “frob/whatever”.

Example configuration settings are below. This is a partial list. Documentation on all the settings is included in the `config.ini` file.

Section main
  database – `db`
    Database directory path. The path may be either absolute or relative to the directory containig this config file.
  templates – `html`
    Path to the HTML templates directory. The path may be either absolute or relative to the directory containing this config file.
  static_files – default blank
    A list of space separated directory paths (or a single directory). These directories hold additional static files available via Web UI. These directories may contain sitewide images, CSS stylesheets etc. If a ‘-’ is included, the list processing ends and the TEMPLATES directory is not searched after the specified directories. If this option is not set, all static files are taken from the TEMPLATES directory.
  admin_email – `roundup-admin`
    Email address that roundup will complain to if it runs into trouble. If the email address doesn’t contain an `@` part, the MAIL_DOMAIN defined below is used.
  dispatcher_email – `roundup-admin`
    The ‘dispatcher’ is a role that can get notified of new items to the database. It is used by the ERROR_MESSAGES_TO config setting. If the email address doesn’t contain an `@` part, the MAIL_DOMAIN defined below is used.
  email_from_tag – default blank
    Additional text to include in the “name” part of the From: address used in nosy messages. If the sending user is “Foo Bar”, the From: line is usually: `"Foo Bar" <issue_tracker@tracker.example>` the EMAIL_FROM_TAG goes inside the “Foo Bar” quotes like so: `"Foo Bar EMAIL_FROM_TAG" <issue_tracker@tracker.example>`
  new_web_user_roles – `User`
    Roles that a user gets when they register with Web User Interface. This is a comma-separated list of role names (e.g. `Admin,User`).
  new_email_user_roles – `User`
    Roles that a user gets when they register with Email Gateway. This is a comma-separated string of role names (e.g. `Admin,User`).
  error_messages_to – `user`
    Send error message emails to the `dispatcher`, `user`, or `both`? The dispatcher is configured using the DISPATCHER_EMAIL setting. Allowed values: `dispatcher`, `user`, or `both`
  html_version – `html4`
    This setting should be left at the default value of html4. Support is ending for xhtml mode. HTML version to generate. The templates are `html4` by default. If you wish to make them xhtml, then you’ll need to change this var to `xhtml` too so all auto-generated HTML is compliant. Allowed values: `html4`, `xhtml`
  timezone – `0`
    Numeric timezone offset used when users do not choose their own in their settings.
  instant_registration – `yes`
    Register new users instantly, or require confirmation via email? Allowed values: `yes`, `no`
  email_registration_confirmation – `yes`
    Offer registration confirmation by email or only through the web? Allowed values: `yes`, `no`
  indexer_stopwords – default blank
    Additional stop-words for the full-text indexer specific to your tracker. See the indexer source for the default list of stop-words (e.g. `A,AND,ARE,AS,AT,BE,BUT,BY, ...`).
  umask – `02`
    Defines the file creation mode mask.
  csv_field_size – `131072`
    Maximum size of a csv-field during import. Roundup’s export format is a csv (comma separated values) variant. The csv reader has a limit on the size of individual fields starting with python 2.5. Set this to a higher value if you get the error ‘Error: field larger than field limit’ during import.

Section tracker
  name – `Roundup issue tracker`
    A descriptive name for your Roundup instance.
  web – `http://host.example/demo/`
    The web address that the tracker is viewable at. This will be included in information sent to users of the tracker. The URL MUST include the cgi-bin part or anything else that is required to get to the home page of the tracker. You MUST include a trailing ‘/’ in the URL.
  email – `issue_tracker`
    Email address that mail to Roundup should go to.
  language – default blank
    Default locale name for this tracker. If this option is not set, the language is determined by the environment variable LANGUAGE, LC_ALL, LC_MESSAGES, or LANG, in that order of preference.

Section web
  allow_html_file – `no`
    Setting this option enables Roundup to serve uploaded HTML file content as HTML. This is a potential security risk and is therefore disabled by default. Set to ‘yes’ if you trust all users uploading content to your tracker.
  http_auth – `yes`
    Whether to use HTTP Basic Authentication, if present. Roundup will use either the REMOTE_USER or HTTP_AUTHORIZATION variables supplied by your web server (in that order). Set this option to ‘no’ if you do not wish to use HTTP Basic Authentication in your web interface.
  use_browser_language – `yes`
    Whether to use HTTP Accept-Language, if present. Browsers send a language-region preference list. It’s usually set in the client’s browser or in their Operating System. Set this option to ‘no’ if you want to ignore it.
  debug – `no`
    Setting this option makes Roundup display error tracebacks in the user’s browser rather than emailing them to the tracker admin.”),

Section rdbms

  Settings in this section are used to set the backend and configure addition settings needed by RDBMs like SQLite, Postgresql and MySQL backends.

  backend – set to value by init
    The database backend such as anydbm, sqlite, mysql or postgres.
  name – `roundup`
    Name of the database to use.
  host – `localhost`
    Database server host.
  port – default blank
    TCP port number of the database server. Postgresql usually resides on port 5432 (if any), for MySQL default port number is 3306. Leave this option empty to use backend default.
  user – `roundup`
    Database user name that Roundup should use.
  password – `roundup`
    Database user password.
  read_default_file – `~/.my.cnf`
    Name of the MySQL defaults file. Only used in MySQL connections.
  read_default_group – `roundup`
    Name of the group to use in the MySQL defaults file. Only used in MySQL connections.
  sqlite_timeout – `30`
    Number of seconds to wait when the SQLite database is locked. Used only for SQLite.
  cache_size – 100
    Size of the node cache (in elements) used to keep most recently used data in memory.

Section logging
  config – default blank
    Path to configuration file for standard Python logging module. If this option is set, logging configuration is loaded from specified file; options ‘filename’ and ‘level’ in this section are ignored. The path may be either absolute or relative to the directory containig this config file.
  filename – default blank
    Log file name for minimal logging facility built into Roundup. If no file name specified, log messages are written on stderr. If above ‘config’ option is set, this option has no effect. The path may be either absolute or relative to the directory containig this config file.
  level – `ERROR`
    Minimal severity level of messages written to log file. If above ‘config’ option is set, this option has no effect. Allowed values: `DEBUG`, `INFO`, `WARNING`, `ERROR`

Section mail

  Outgoing email options. Used for nosy messages, password reset and registration approval requests.

  domain – `localhost`
    Domain name used for email addresses.
  host – default blank
    SMTP mail host that Roundup will use to send mail
  username – default blank
    SMTP login name. Set this if your mail host requires authenticated access. If username is not empty, password (below) MUST be set!
  password – default blank
    SMTP login password. Set this if your mail host requires authenticated access.
  port – default 25
    SMTP port on mail host. Set this if your mail host runs on a different port.
  local_hostname – default blank
    The fully qualified domain name (FQDN) to use during SMTP sessions. If left blank, the underlying SMTP library will attempt to detect your FQDN. If your mail host requires something specific, specify the FQDN to use.
  tls – `no`
    If your SMTP mail host provides or requires TLS (Transport Layer Security) then you may set this option to ‘yes’. Allowed values: `yes`, `no`
  tls_keyfile – default blank
    If TLS is used, you may set this option to the name of a PEM formatted file that contains your private key. The path may be either absolute or relative to the directory containig this config file.
  tls_certfile – default blank
    If TLS is used, you may set this option to the name of a PEM formatted certificate chain file. The path may be either absolute or relative to the directory containig this config file.
  charset – utf-8
    Character set to encode email headers with. We use utf-8 by default, as it’s the most flexible. Some mail readers (eg. Eudora) can’t cope with that, so you might need to specify a more limited character set (eg. iso-8859-1).
  debug – default blank
    Setting this option makes Roundup to write all outgoing email messages to this file instead of sending them. This option has the same effect as environment variable SENDMAILDEBUG. Environment variable takes precedence. The path may be either absolute or relative to the directory containig this config file.
  add_authorinfo – `yes`
    Add a line with author information at top of all messages send by Roundup.
  add_authoremail – `yes`
    Add the mail address of the author to the author information at the top of all messages. If this is false but add_authorinfo is true, only the name of the actor is added which protects the mail address of the actor from being exposed at mail archives, etc.

Section mailgw

  Roundup Mail Gateway options

  keep_quoted_text – `yes`
    Keep email citations when accepting messages. Setting this to `no` strips out “quoted” text from the message. Signatures are also stripped. Allowed values: `yes`, `no`
  leave_body_unchanged – `no`
    Preserve the email body as is - that is, keep the citations and signatures. Allowed values: `yes`, `no`
  default_class – `issue`
    Default class to use in the mailgw if one isn’t supplied in email subjects. To disable, leave the value blank.
  language – default blank
    Default locale name for the tracker mail gateway. If this option is not set, mail gateway will use the language of the tracker instance.
  subject_prefix_parsing – `strict`
    Controls the parsing of the [prefix] on subject lines in incoming emails. `strict` will return an error to the sender if the [prefix] is not recognised. `loose` will attempt to parse the [prefix] but just pass it through as part of the issue title if not recognised. `none` will always pass any [prefix] through as part of the issue title.
  subject_suffix_parsing – `strict`
    Controls the parsing of the [suffix] on subject lines in incoming emails. `strict` will return an error to the sender if the [suffix] is not recognised. `loose` will attempt to parse the [suffix] but just pass it through as part of the issue title if not recognised. `none` will always pass any [suffix] through as part of the issue title.
  subject_suffix_delimiters – `[]`
    Defines the brackets used for delimiting the commands suffix in a subject line.
  subject_content_match – `always`
    Controls matching of the incoming email subject line against issue titles in the case where there is no designator [prefix]. `never` turns off matching. `creation + interval` or `activity + interval` will match an issue for the interval after the issue’s creation or last activity. The interval is a standard Roundup interval.
  subject_updates_title – `yes`
    Update issue title if incoming subject of email is different. Setting this to `no` will ignore the title part of the subject of incoming email messages.
  refwd_re – `(\s*\W?\s*(fw|fwd|re|aw|sv|ang)\W)+`
    Regular expression matching a single reply or forward prefix prepended by the mailer. This is explicitly stripped from the subject during parsing. Value is Python Regular Expression (UTF8-encoded).
  origmsg_re – `` ^[>|s]*—–s?Original Messages?—–$``
    Regular expression matching start of an original message if quoted in the body. Value is Python Regular Expression (UTF8-encoded).
  sign_re – `^[>|\s]*-- ?$`
    Regular expression matching the start of a signature in the message body. Value is Python Regular Expression (UTF8-encoded).
  eol_re – `[\r\n]+`
    Regular expression matching end of line. Value is Python Regular Expression (UTF8-encoded).
  blankline_re – `[\r\n]+\s*[\r\n]+`
    Regular expression matching a blank line. Value is Python Regular Expression (UTF8-encoded).
  ignore_alternatives – `no`
    When parsing incoming mails, Roundup uses the first text/plain part it finds. If this part is inside a multipart/alternative, and this option is set, all other parts of the multipart/alternative are ignored. The default is to keep all parts and attach them to the issue.

Section pgp

  OpenPGP mail processing options

  enable – `no`
    Enable PGP processing. Requires gpg.
  roles – default blank
    If specified, a comma-separated list of roles to perform PGP processing on. If not specified, it happens for all users.
  homedir – default blank
    Location of PGP directory. Defaults to $HOME/.gnupg if not specified.

Section nosy

  Nosy messages sending

  messages_to_author – `no`
    Send nosy messages to the author of the message. If `yes` is used, then messages are sent to the author even if not on the nosy list, same for `new` (but only for new messages). When set to `nosy`, the nosy list controls sending messages to the author. Allowed values: `yes`, `no`, `new`, `nosy`
  signature_position – `bottom`
    Where to place the email signature. Allowed values: `top`, `bottom`, `none`
  add_author – `new`
    Does the author of a message get placed on the nosy list automatically? If `new` is used, then the author will only be added when a message creates a new issue. If `yes`, then the author will be added on followups too. If `no`, they’re never added to the nosy. Allowed values: `yes`, `no`, `new`
  add_recipients – `new`
    Do the recipients (`To:`, `Cc:`) of a message get placed on the nosy list? If `new` is used, then the recipients will only be added when a message creates a new issue. If `yes`, then the recipients will be added on followups too. If `no`, they’re never added to the nosy. Allowed values: `yes`, `no`, `new`
  email_sending – `single`
    Controls the email sending from the nosy reactor. If `multiple` then a separate email is sent to each recipient. If `single` then a single email is sent with each recipient as a CC address.
  max_attachment_size – `2147483647`
    Attachments larger than the given number of bytes won’t be attached to nosy mails. They will be replaced by a link to the tracker’s download page for the file.

You may generate a new default config file using the `roundup-admin genconfig` command. You can generate a new config file merging in existing settings using the `roundup-admin updateconfig` command.

Configuration variables may be referred to in lower or upper case. In code, variables not in the “main” section are referred to using their section and name, so “domain” in the section “mail” becomes MAIL_DOMAIN.

### Extending the configuration file

You can’t add new variables to the config.ini file in the tracker home but you can add two new config.ini files:

- a config.ini in the `extensions` directory will be loaded and attached to the config variable as “ext”.
- a config.ini in the `detectors` directory will be loaded and attached to the config variable as “detectors”.

For example, the following in `detectors/config.ini`:

    [main]
    qa_recipients = email@example.com

is accessible as:

    db.config.detectors['QA_RECIPIENTS']

Note that the name grouping applied to the main configuration file is applied to the extension config files, so if you instead have:

    [qa]
    recipients = email@example.com

then the above `db.config.detectors['QA_RECIPIENTS']` will still work.

Unlike values in the tracker’s main `config.ini`, the values defined in these config files are not validated. For example: a setting that is supposed to be an integer value (e.g. 4) could be the word “foo”. If you are writing Python code that uses these settings, you should expect to handle invalid values.

Also, incorrect values aren’t discovered until the config setting is used. This can be long after the tracker is started and the error may not be seen in the logs.

It is possible to validate these settings. Validation involves calling the `update_options` method on the configuration option. This can be done from the `init()` function in the Python files implementing extensions or detectors.

As an example, adding the following to an extension:

    from roundup.configuration import SecretMandatoryOption

    def init(instance):
        instance.config.ext.update_option('RECAPTCHA_SECRET',
            SecretMandatoryOption,description="Secret securing reCaptcha.")

similarly for a detector:

    from roundup.configuration import MailAddressOption

    def init(db):
        try:
            db.config.detectors.update_option('QA_RECIPIENTS',
                MailAddressOption,
                description="Email used for QA comment followup.")
        except KeyError:
            # COMMENT_EMAIL setting is not found, but it's optional
            # so continue
            pass

will allow reading the secret from a file or append the tracker domain to an email address if it does not have a domain.

Running `roundup-admin -i tracker_home display user1` will validate the settings for both config.ini`s. Otherwise detector options are not validated until the first request to the web interface (or email gateway).

There are 4 arguments for `update_option`:

1. config setting name - string (positional, mandatory)
2. option type - Option derived class from configuration.py (positional, mandatory)
3. default value - string (optional, named default)
4. description - string (optional, named description)

The first argument is the config setting name as described at the beginning of this section.

The second argument is a class in the roundup.configuration module. There are a number of these classes: BooleanOption, IntegerNumberOption, RegExpOption…. Please see the configuration module for all Option validators and their descriptions. You can also define your own custom validator in interfaces.py.

The third and fourth arguments are strings and are optional. They are printed if there is an error and may help the user correct the problem.

## Tracker Schema

Note

if you modify the schema, you’ll most likely need to edit the web interface HTML template files and detectors to reflect your changes.

A tracker schema defines what data is stored in the tracker’s database. Schemas are defined using Python code in the `schema.py` module of your tracker.

### What you can/can’t do to the schema

Your schema may be changed at any time before or after the tracker has been initialised (or used). You may:

Add new properties to classes, or add whole new classes
  This is painless and easy to do - there are generally no repercussions from adding new information to a tracker’s schema.
Remove properties
  Removing properties is a little more tricky - you need to make sure that the property is no longer used in the web interface or by the detectors.

You must never:

Remove the user class
  This class is the only required class in Roundup.
Remove the “username”, “address”, “password” or “realname” user properties
  Various parts of Roundup require these properties. Don’t remove them.
Change the type of a property
  Property types must never [1] be changed - the database simply doesn’t take this kind of action into account. Note that you can’t just remove a property and re-add it as a new type either. If you wanted to make the assignedto property a Multilink, you’d need to create a new property assignedto_list and remove the old assignedto property.

[1] | If you shut down the tracker, export the database, modify the exported csv property data to be compatible with the new type, change the property type in the schema, and finally import the changed exported data, you can change the property type. It is not trivial nor for the faint of heart. But it can be done.

### The `schema.py` and `initial_data.py` modules

The schema.py module is used to define what your tracker looks like on the inside, the schema of the tracker. It defines the Classes and properties on each class. It also defines the security for those Classes. The next few sections describe how schemas work and what you can do with them.

The initial_data.py module sets up the initial state of your tracker. It’s called exactly once - by the `roundup-admin initialise` command. See the start of the section on database content for more info about how this works.

### The “classic” schema

The “classic” schema looks like this (see section setkey(property) below for the meaning of `'setkey'` – you may also want to look into the sections setlabelprop(property) and setorderprop(property) for specifying (default) labelling and ordering of classes.):

    pri = Class(db, "priority", name=String(), order=String())
    pri.setkey("name")

    stat = Class(db, "status", name=String(), order=String())
    stat.setkey("name")

    keyword = Class(db, "keyword", name=String())
    keyword.setkey("name")

    user = Class(db, "user", username=String(), organisation=String(),
        password=String(), address=String(), realname=String(),
        phone=String(), alternate_addresses=String(),
        queries=Multilink('query'), roles=String(), timezone=String())
    user.setkey("username")

    msg = FileClass(db, "msg", author=Link("user"), summary=String(),
        date=Date(), recipients=Multilink("user"),
        files=Multilink("file"), messageid=String(), inreplyto=String())

    file = FileClass(db, "file", name=String())

    issue = IssueClass(db, "issue", keyword=Multilink("keyword"),
        status=Link("status"), assignedto=Link("user"),
        priority=Link("priority"))
    issue.setkey('title')

### Classes and Properties - creating a new information store

In the tracker above, we’ve defined 7 classes of information:

> priority
>   Defines the possible levels of urgency for issues.
> status
>   Defines the possible states of processing the issue may be in.
> keyword
>   Initially empty, will hold keywords useful for searching issues.
> user
>   Initially holding the “admin” user, will eventually have an entry for all users using Roundup.
> msg
>   Initially empty, will hold all e-mail messages sent to or generated by Roundup.
> file
>   Initially empty, will hold all files attached to issues.
> issue
>   Initially empty, this is where the issue information is stored.

We define the “priority” and “status” classes to allow two things:

> 1. reduction in the amount of information stored on the issue
> 2. more powerful, accurate searching of issues by priority and status

By only requiring a link on the issue (which is stored as a single number) we reduce the chance that someone mis-types a priority or status - or simply makes a new one up.

Class names are used to access items of that class in the REST api interface. The classic tracker was created before the REST interface was added. It uses the single form (i.e. issue and user not issues and users) for its classes. Most REST documentation suggests using plural forms. However, to make your API consistent, use singular forms for classes that you add.

#### Class and Items

A Class defines a particular class (or type) of data that will be stored in the database. A class comprises one or more properties, which gives the information about the class items.

The actual data entered into the database, using `class.create()`, are called items. They have a special immutable property called `'id'`. We sometimes refer to this as the itemid.

#### Properties

A Class is comprised of one or more properties of the following types:

String
  properties are for storing arbitrary-length strings.
Password
  properties are for storing encoded arbitrary-length strings. The default encoding is defined on the `roundup.password.Password` class.
Date
  properties store date-and-time stamps. Their values are Timestamp objects.
Interval
  properties store time periods rather than absolute dates. For example 2 hours.
Integer
  properties store integer values. (Number can store real/float values.)
Number
  properties store numeric values. There is an option to use double-precision floating point numbers.
Boolean
  properties store on/off, yes/no, true/false values.
Link
  properties refers to a single other item selected from a specified class. The class is part of the property; the value is an integer, the id of the chosen item.
Multilink
  properties refer to possibly many items in a specified class. The value is a list of integers.

Properties can have additional attributes to change the default behaviour:

- All properties support the following attributes:

  - `required`: see design documentation. Adds the property to the list returned by calling get_required_props for the class.

  - `default_value`: see design documentation Sets the default value if the property is not set.

  - `quiet`: see design documentation. Suppresses user visible to changes to this property. The property change is not reported:

    - in the change feedback/confirmation message in the web interface
    - the property change section of the nosy email
    - the web history at the bottom of an item’s page

    This can be used to store state of the user interface (e.g. the names of elements that are collapsed or hidden from the user). Making properties that are updated as an indirect result of a user’s change (e.g. updating a blockers property, counting number of times an issue was reopened or reassigned etc.) should not be displayed to the user as they can be confusing.

- String properties can have an `indexme` attribute that defines if the property should be part of the full text index. The default is ‘no’ but this can be set to ‘yes’ to allow a property’s contents to be in the full text index.

- Number properties can have a `use_double` attribute that, when set to `True`, will use double precision floating point in the database.

- Link and Multilink properties can have several attributes:

  - `do_journal`: By default, every change of a link property is recorded in the item being linked to (or being unlinked). A typical use-case for setting `do_journal='no'` would be to turn off journalling of nosy list, message author and message recipient link and unlink events to prevent the journal from clogged with these events.
  - `try_id_parsing` is turned on by default. If entering a number into a Link or Multilink field, Roundup interprets this number as an ID of the item to link to. Sometimes items can have numeric names (like, e.g., product codes). For these Roundup needs to match the numeric name and should never match an ID. In this case you can set `try_id_parsing='no'`.

  - The `rev_multilink` option takes a property name to be inserted into the linked-to class. This property is a Multilink property that links back to the current class. The new Multilink is read-only (it is automatically modified if the Link or Multilink property defining it is modified). The new property can be used in normal searches using the “filter” method of the Class. This means it can be used like other Multilink properties when searching (in an index template) or via the REST and XMLRPC APIs.

    As a example, suppose you want to group multiple issues into a super issue. Each issue can be part of only one super issue. It is inefficient to find all of the issues that are part of the super issue by searching through all issues in the system looking at the part_of link property. To make this more efficient, you can declare an issue’s part_of property as:

        issue = IssueClass(db, "issue",
                  ...
                  part_of = Link("issue", rev_multilink="components"),
                  ... )

    This automatically creates the `components` multilink on the issue class. The `components` multilink is never explicitly declared in the issue class, but it has the same effect as though you had declared the class as:

        issue = IssueClass(db, "issue",
                  ...
                  part_of = Link("issue"),
                  components = Multilink("issue"),
                  ... )

    Then wrote a detector to update the components property on the corresponding issue. Writing this detector can be tricky. There is one other difference, you can not explicitly set/modify the `components` multilink.

    The effect of setting `part_of = 3456` on issue1234 automatically adds “1234” to the `components` property on issue3456. You can search the `components` multilink just like a regular multilink, but you can’t explicitly assign to it. Another difference of reverse multilinks to normal multilinks is that when a linked node is retired, the node vanishes from the multilink, e.g. in the example above, if an issue with `part_of` set to another issue is retired this issue vanishes from the `components` multilink of the other issue.

    You can also link between different classes. So you can modify the issue definition to include:

        issue = IssueClass(db, "issue",
                  ...
                  assigned_to = Link("user", rev_multilink="responsibleFor"),
                  ... )

    This makes it easy to list all issues that the user is responsible for (aka assigned_to).

  - The `msg_header_property` is used by the mail gateway when sending out messages. When a link or multilink property of an issue changes, Roundup creates email headers of the form:

        X-Roundup-issue-prop: value

    where `value` is the `name` property for the linked item(s). For example, if you have a multilink for attached_files in your issue, you will see a header:

        X-Roundup-issue-attached_files: MySpecialFile.doc, HisResume.txt

    when the class for attached files is defined as:

        file = FileClass(db, "file", name=String())

    `MySpecialFile.doc` is the name for the file object.

    If you have an `assigned_to` property in your issue class that links to the user class and you want to add a header:

        X-Roundup-issue-assigned_to: ...

    so that the mail recipients can filter emails where `X-Roundup-issue-assigned_to: name` that contains their username. The user class is defined as:

        user = Class(db, "user",
                 username=String(),
                 password=Password(),
                 address=String(),
                 realname=String(),
                 phone=String(),
                 organisation=String(),
                 alternate_addresses=String(),
                 queries=Multilink('query'),
                 roles=String(),     # comma-separated string of Role names
                 timezone=String())

    Because there is no `name` parameter for the user class, there will be no header. However setting:

        assigned_to=Link("user", msg_header_property="username")

    will make the mail gateway generate an `X-Roundup-issue-assigned_to` using the username property of the linked user.

    Assume assigned_to for an issue is linked to the user with username=joe_user, setting:

        msg_header_property="username"

    for the assigned_to property will generated message headers of the form:

        X-Roundup-issue-assigned_to: joe_user

    for emails sent on issues where joe_user has been assigned to the issue.

    If this property is set to the empty string “”, it will prevent the header from being generated on outgoing mail.

All Classes automatically have a number of properties by default:

creator
  Link to the user that created the item.
creation
  Date the item was created.
actor
  Link to the user that last modified the item.
activity
  Date the item was last modified.

#### Methods

All classes have the following methods.

##### setkey(property)

Select a String property of the class to be the key property. The key property must be unique, and allows references to the items in the class by the content of the key property. That is, we can refer to users by their username: for example, let’s say that there’s an issue in Roundup, issue 23. There’s also a user, richard, who happens to be user 2. To assign an issue to him, we could do either of:

    roundup-admin set issue23 assignedto=2

or:

    roundup-admin set issue23 assignedto=richard

Note, the same thing can be done in the web and e-mail interfaces.

##### setlabelprop(property)

Select a property of the class to be the label property. The label property is used whereever an item should be uniquely identified, e.g., when displaying a link to an item. If setlabelprop is not specified for a class, the following values are tried for the label:

- the key of the class (see the setkey(property) section above)
- the “name” property
- the “title” property
- the first property from the sorted property name list

So in most cases you can get away without specifying setlabelprop explicitly.

You should make sure that users have View access to this property or the id property for a class. If the property can not be viewed by a user, looping over items in the class (e.g. messages attached to an issue) will not work.

##### setorderprop(property)

Select a property of the class to be the order property. The order property is used whenever using a default sort order for the class, e.g., when grouping or sorting class A by a link to class B in the user interface, the order property of class B is used for sorting. If setorderprop is not specified for a class, the following values are tried for the order property:

- the property named “order”
- the label property (see setlabelprop(property) above)

So in most cases you can get away without specifying setorderprop explicitly.

##### create(information)

Create an item in the database. This is generally used to create items in the definitional class like “priority” and “status”.

#### IssueClass

IssueClasses automatically include the “messages”, “files”, “nosy”, and “superseder” properties.

The messages and files properties list the links to the messages and files related to the issue. The nosy property is a list of links to users who wish to be informed of changes to the issue - they get “CC’ed” e-mails when messages are sent to or generated by the issue. The nosy reactor (in the `'detectors'` directory) handles this action. The superseder link indicates an issue which has superseded this one.

They also have the dynamically generated “creation”, “activity” and “creator” properties.

The value of the “creation” property is the date when an item was created, and the value of the “activity” property is the date when any property on the item was last edited (equivalently, these are the dates on the first and last records in the item’s journal). The “creator” property holds a link to the user that created the issue.

#### FileClass

FileClasses save their “content” attribute off in a separate file from the rest of the database. This reduces the number of large entries in the database, which generally makes databases more efficient, and also allows us to use command-line tools to operate on the files. They are stored in the files sub-directory of the `'db'` directory in your tracker. FileClasses also have a “type” attribute to store the MIME type of the file.

Roundup by default considers the contents of the file immutable. This is to assist in maintaining an accurate record of correspondence. The distributed tracker templates do not enforce this. So if you have access to the Roundup tracker directory, you can edit the files (make sure to preserve mode, owner and group) to remove information (e.g. if somebody includes a password or you need to redact proprietary information). Obviously the journal for the message/file will not report that the file has changed.

Best practice is to remove offending material and leave a placeholder. E.G. replace a password with the text:

    [password has been deleted 2020-12-02 --myname]

If you need to delete an entire file, replace the file contents with:

    [file contents deleted due to spam 2020-10-21 --myname]

rather than deleting the file. If you actually delete the file Roundup will report an error to the user and email the administrator. If you empty the file, a user downloading the file using the direct URL (e.g. `tracker/msg22`) may be confused and think something is broken when they receive an empty file. Retiring a file/msg does not prevent access to the file using the direct URL. Retiring an item only removes it when requesting a list of all items in the class. If you are replacing the contents, you probably want to change the content type of the file. E.G. from `image/jpeg` to `text/plain`. You can do this easily through the web interface, or using the `roundup-admin` command line interface.

You can also change the contents of a file or message using the REST interface. Note that this will NOT result in an entry in the journal, so again it allows a silent change. To do this you need to make two rest requests. An example using curl is:

    $ curl -u demo:demo -s
           -H "X-requested-with: rest" \
           -H "Referer:  https://tracker.example.com/demo/" \
           -X GET \
           https://tracker.example.com/demo/rest/data/file/30/content
    {
       "data": {
           "id": "30",
           "type": "<class 'str'>",
           "link": "https://tracker.example.com/demo/rest/data/file/30/content",
           "data": "hello3",
           "@etag": "\"3f2f8063dbce5b6bd43567e6f4f3c671\""
       }
    }

using the etag, overwrite the content with:

    $ curl -u demo:demo -s
          -H "X-requested-with: rest" \
          -H "Referer:  https://tracker.example.com/demo/" \
          -H 'If-Match: "3f2f8063dbce5b6bd43567e6f4f3c671"' \
          -X PUT \
          -F "data=@hello" \
          https://tracker.example.com/demo/rest/data/file/30/content

where `hello` is a file on local disk.

You can enforce immutability in your tracker by adding an auditor (see detectors) for the file/msg class that rejects changes to the content property. The auditor could also add a journal entry so that a change via the Roundup mechanism is reported. Using a mixin (see: https://wiki.roundup-tracker.org/MixinClassFileClass) to augment the file class allows for other possibilities including signing the file, or recording a checksum in the database and validating the file contents at the time it gets read. This allows detection of changes done on the filesystem outside of the Roundup mechanism.

#### A note about ordering

When we sort items in the hyperdb, we use one of a number of methods, depending on the properties being sorted on:

1. If it’s a String, Integer, Number, Date or Interval property, we just sort the scalar value of the property. Strings are sorted case-sensitively.
2. If it’s a Link property, we sort by either the linked item’s “order” property (if it has one) or the linked item’s “id”.
3. Mulitlinks sort similar to #2, but we start with the first Multilink list item, and if they’re the same, we sort by the second item, and so on.

Note that if an “order” property is defined on a Class that is used for sorting, all items of that Class must have a value against the “order” property, or sorting will result in random ordering.

### Examples of adding to your schema

Some examples are in the Examples section.

Also you can start with Roundup wiki CategorySchema to see a list of additional examples of how schemas can be customised to add new functionality.

### Schema Integrity

There is a table in all SQL based schemas called `schema`. It contains a representation of the current schema and the current Roundup schema version. Roundup will exit the version is not supported by the release. E.G. Roundup 2.1.0 will not work with a database created by 2.3.0 as db version 8 used by 2.3.0 is not supported by 2.1.0.

The current schema representation is automatically updated whenever a change is made to the schema via `schema.py`. The schema version is upgraded when running `roundup-admin migrate` although it can be upgraded automatically in some cases by run a Roundup process (mailgw, web interface). This information is kept in one large blob in the table. To view this in a more understandable format, you can use the commands below (requires the jq command):

Postgres

      psql -tq -d 'roundup_db'  -U roundup_user -c \
         'select schema from schema;' | \
         python3 -c 'import json, sys; d = eval(sys.stdin.read()); \
         print(json.dumps(d, indent=2));' | jq . | less

replace `roundup_db`, `roundup_user` with the values from `config.ini` and use a `~/.pgpass` file or type the database password when prompted.

SQLite

      sqlite3 demo/db/db 'select schema from schema;' | \
        python3 -c 'import json, sys; d = eval(sys.stdin.read()); \
        print(json.dumps(d, indent=2));' | jq . | less

Something similar for MySQL can be generated as well. Replacing `jq .` with `jq .version` will display the schema version.

## Detectors - adding behaviour to your tracker

Detectors are initialised every time you open your tracker database, so you’re free to add and remove them any time, even after the database is initialised via the `roundup-admin initialise` command.

The detectors in your tracker fire before (auditors) and after (reactors) changes to the contents of your database. They are Python modules that sit in your tracker’s `detectors` directory. You will have some installed by default - have a look. You can write new detectors or modify the existing ones. The existing detectors installed for you are:

nosyreaction.py
  This provides the automatic nosy list maintenance and email sending. The nosy reactor (`nosyreaction`) fires when new messages are added to issues. The nosy auditor (`updatenosy`) fires when issues are changed, and figures out what changes need to be made to the nosy list (such as adding new authors, etc.)
statusauditor.py
  This provides the `chatty` auditor which changes the issue status from `unread` or `closed` to `chatting` if new messages appear. It also provides the `presetunread` auditor which pre-sets the status to `unread` on new items if the status isn’t explicitly defined.
messagesummary.py
  Generates the `summary` property for new messages based on the message content.
userauditor.py
  Verifies the content of some of the user fields (email addresses and roles lists).

If you don’t want this default behaviour, you’re completely free to change or remove these detectors.

See the detectors section in the design document for details of the interface for detectors.

### Detector API

Auditors are called with the arguments:

    audit(db, cl, itemid, newdata)

where `db` is the database, `cl` is an instance of Class or IssueClass within the database, and `newdata` is a dictionary mapping property names to values.

For a `create()` operation, the `itemid` argument is None and newdata contains all of the initial property values with which the item is about to be created.

For a `set()` operation, newdata contains only the names and values of properties that are about to be changed.

For a `retire()` or `restore()` operation, newdata is None.

Reactors are called with the arguments:

    react(db, cl, itemid, olddata)

where `db` is the database, `cl` is an instance of Class or IssueClass within the database, and `olddata` is a dictionary mapping property names to values.

For a `create()` operation, the `itemid` argument is the id of the newly-created item and `olddata` is None.

For a `set()` operation, `olddata` contains the names and previous values of properties that were changed.

For a `retire()` or `restore()` operation, `itemid` is the id of the retired or restored item and `olddata` is None.

### Additional Detectors Ready For Use

Sample additional detectors that have been found useful will appear in the `'detectors'` directory of the Roundup distribution. If you want to use one, copy it to the `'detectors'` of your tracker instance:

irker.py
  This detector sends notification on IRC through an irker daemon (http://www.catb.org/esr/irker/) when issues are created or messages are added. In order to use it you need to install irker, start the irkerd daemon, and add an `[irker]` section in `detectors/config.ini` that contains a comma-separated list of channels where the messages should be sent, e.g. `channels = irc://chat.freenode.net/channelname`.
newissuecopy.py
  This detector sends an email to a team address whenever a new issue is created. The address is hard-coded into the detector, so edit it before you use it (look for the text ‘team@team.host’) or you’ll get email errors!
creator_resolution.py
  Catch attempts to set the status to “resolved” - if the assignedto user isn’t the creator, then set the status to “confirm-done”. Note that “classic” Roundup doesn’t have that status, so you’ll have to add it. If you don’t want to though, it’ll just use “in-progress” instead.
email_auditor.py
  If a file added to an issue is of type message/rfc822, we tack on the extension .eml. The reason for this is that Microsoft Internet Explorer will not open things with a .eml attachment, as they deem it ‘unsafe’. Worse yet, they’ll just give you an incomprehensible error message. For more information, see the detector code - it has a lengthy explanation.

### Auditor or Reactor?

Generally speaking, the following rules should be observed:

Auditors
  Are used for vetoing creation of or changes to items. They might also make automatic changes to item properties.
Reactors
  Detect changes in the database and react accordingly. They should avoid making changes to the database where possible, as this could create detector loops.

### Vetoing creation of or changes to items

Auditors may raise the `Reject` exception to prevent the creation of or changes to items in the database. The mail gateway, for example, will not attach files or messages to issues when the creation of those files or messages are prevented through the `Reject` exception. It’ll also not create users if that creation is `Reject`’ed too.

To use, simply add at the top of your auditor:

    from roundup.exceptions import Reject

And then when your rejection criteria have been detected, simply:

    raise Reject('Description of error')

Error messages raised with `Reject` automatically have any HTML content escaped before being displayed to the user. To display an error message to the user without performing any HTML escaping the `RejectRaw` should be used. All security implications should be carefully considering before using `RejectRaw`.

### Generating email from Roundup

The module `roundup.mailer` contains most of the nuts-n-bolts required to generate email messages from Roundup.

In addition, the `IssueClass` methods `nosymessage()` and `send_message()` are used to generate nosy messages, and may generate messages which only consist of a change note (ie. the message id parameter is not required - this is referred to as a “System Message” because it comes from “the system” and not a user).

## Extensions - adding capabilities to your tracker

While detectors add new behavior by reacting to changes in tracked objects, extensions add new actions and utilities to Roundup, which are mostly used to enhance web interface.

You can create an extension by creating Python file in your tracker `extensions` directory. All files from this dir are loaded when tracker instance is created, at which point it calls `init(instance)` from each file supplying itself as a first argument.

Note that at this point web interface is not loaded, but extensions still can register actions for in tracker instance. This may be fixed in Roundup 1.6 by introducing `init_web(client)` callback or a more flexible extension point mechanism.

- `instance.registerUtil` is used for adding templating utilities (see adding a time log to your issues for an example)
- `instance.registerAction` is used to add more actions to instance and to web interface. See Defining new web actions for details. Generic action can be added by inheriting from `action.Action` instead of `cgi.action.Action`.

## interfaces.py - hooking into the core of Roundup

There is a magic trick for hooking into the core of Roundup. Using this you can:

- modify class data structures
- monkey patch core code to add new functionality
- modify the email gateway
- add new rest endpoints
- enable experimental or future features

but with great power comes great responsibility.

Interfaces.py has been around since the earliest releases of Roundup and used to be the main way to get a lot of customisation done. In modern Roundup, the extensions mechanism is used to add actions and templating utilities. But there are places where interfaces.py is still useful. Note that the tracker directories are not on the Python system path when interfaces.py is evaluated. You need to add library directories explictly by modifying sys.path.

See Changing How the Core Code Works for examples.

## Database Content

Note

If you modify the content of a definitional class, you will need to edit the tracker detectors if they reference a value of a definitional class. (E.g. if a detector checks to see if an issue has a status of “open”, and you change the “open” definition to be “working”, you need to change the check.)

Customisation of the special definitional classes (eg. status, priority, resolution, …) may be done either before or after the tracker is initialised. The actual method of doing so is completely different in each case though, so be careful to use the right one.

Changing content before tracker initialisation
  Edit the initial_data.py module in your tracker to alter the items created using the `create( ... )` methods.
Changing content after tracker initialisation

  As the “admin” user, click on the “class list” link in the web interface to bring up a list of all database classes. Click on the name of the class you wish to change the content of.

  You may also use the `roundup-admin` interface’s create, set and retire methods to add, alter or remove items from the classes in question.

See “adding a new field to the classic schema” for an example that requires database content changes.

## Security / Access Controls

A set of Permissions is built into the security module by default. For each Class defined in the tracker schema, the following permissions are defined:

- Create (everything)
- Edit (everything)
- Search (everything) - (used if View does not permit access)
- Retire (everything)
- Restore (everything)
- View (everything)

All of these are assigned to the “Admin” Role by default for every class. They allow a user to do anything. The web and email interfaces also define:

Email Access
  If defined, the user may use the email interface. Used by default to deny Anonymous users access to the email interface. When granted to the Anonymous user, they will be automatically registered by the email interface (see also the `new_email_user_roles` configuration option).
Web Access
  If defined, the user may use the web interface. This is usually assigned to the Anonymous role as well to allow authorized users to access the form based login. If some other authorization mode (basic auth, SSO, etc.) is used Web Access can be removed from the Anonymous user.
Web Roles
  Controls user access to editing the “roles” property of the “user” class. TODO: deprecate in favour of a property-based control.
Rest Access
Xmlrpc Access
  These control access to the Rest and Xmlrpc endpoints. The Admin and User roles have these by default in the classic tracker. See the directions in the rest interface documentation and the xmlrpc interface documentation.
Register
  This is assigned to the anonymous user and allows automatic user registration by email or web.

These are hooked into the default Roles:

- Admin (Create, Edit, Retire, Restore, Search, View for everything; Web Roles)
- User (Web Access; Email Access)
- Anonymous (Web Access)

Finally, the “admin” user gets the “Admin” Role, and the “anonymous” user gets the “Anonymous” Role assigned when the tracker is installed.

For the “User” Role, the “classic” tracker defines:

- Create, Edit and View issue, file, msg, query, keyword
- View priority, status
- View user
- Edit their own user record

And the “Anonymous” Role is defined as:

- Web interface access
- Register user (for registration)
- View issue, file, msg, query, keyword, priority, status

Put together, these settings appear in the tracker’s `schema.py` file:

    #
    # TRACKER SECURITY SETTINGS
    #
    # See the configuration and customisation document for information
    # about security setup.

    #
    # REGULAR USERS
    #
    # Give the regular users access to the web and email interface
    db.security.addPermissionToRole('User', 'Web Access')
    db.security.addPermissionToRole('User', 'Email Access')
    db.security.addPermissionToRole('User', 'Rest Access')
    db.security.addPermissionToRole('User', 'Xmlrpc Access')

    # Assign the access and edit Permissions for issue, file and message
    # to regular users now
    for cl in 'issue', 'file', 'msg', 'keyword':
        db.security.addPermissionToRole('User', 'View', cl)
        db.security.addPermissionToRole('User', 'Edit', cl)
        db.security.addPermissionToRole('User', 'Create', cl)
    for cl in 'priority', 'status':
        db.security.addPermissionToRole('User', 'View', cl)

    # May users view other user information? Comment these lines out
    # if you don't want them to
    p = db.security.addPermission(name='View', klass='user',
        properties=('id', 'organisation', 'phone', 'realname', 'timezone',
        'username'))
    db.security.addPermissionToRole('User', p)

    # Users should be able to edit their own details -- this permission is
    # limited to only the situation where the Viewed or Edited item is their own.
    def own_record(db, userid, itemid, **ctx):
        '''Determine whether the userid matches the item being accessed.'''
        return userid == itemid
    p = db.security.addPermission(name='View', klass='user', check=own_record,
        description="User is allowed to view their own user details")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Edit', klass='user', check=own_record,
        properties=('username', 'password', 'address', 'realname', 'phone',
            'organisation', 'alternate_addresses', 'queries', 'timezone'),
        description="User is allowed to edit their own user details")
    db.security.addPermissionToRole('User', p)

    # Users should be able to edit and view their own queries. They should also
    # be able to view any marked as not private. They should not be able to
    # edit others' queries, even if they're not private
    def view_query(db, userid, itemid):
        private_for = db.query.get(itemid, 'private_for')
        if not private_for: return True
        return userid == private_for
    def edit_query(db, userid, itemid):
        return userid == db.query.get(itemid, 'creator')
    p = db.security.addPermission(name='View', klass='query', check=view_query,
        description="User is allowed to view their own and public queries")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Search', klass='query')
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Edit', klass='query', check=edit_query,
        description="User is allowed to edit their queries")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Retire', klass='query', check=edit_query,
        description="User is allowed to retire their queries")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Restore', klass='query', check=edit_query,
        description="User is allowed to restore their queries")
    db.security.addPermissionToRole('User', p)
    p = db.security.addPermission(name='Create', klass='query',
        description="User is allowed to create queries")
    db.security.addPermissionToRole('User', p)

    #
    # ANONYMOUS USER PERMISSIONS
    #
    # Let anonymous users access the web interface. Note that almost all
    # trackers will need this Permission. The only situation where it's not
    # required is in a tracker that uses an HTTP Basic Authenticated front-end.
    db.security.addPermissionToRole('Anonymous', 'Web Access')

    # Let anonymous users access the email interface (note that this implies
    # that they will be registered automatically, hence they will need the
    # "Create" user Permission below)
    # This is disabled by default to stop spam from auto-registering users on
    # public trackers.
    #db.security.addPermissionToRole('Anonymous', 'Email Access')

    # Assign the appropriate permissions to the anonymous user's Anonymous
    # Role. Choices here are:
    # - Allow anonymous users to register
    db.security.addPermissionToRole('Anonymous', 'Register', 'user')

    # Allow anonymous users access to view issues (and the related, linked
    # information)
    for cl in 'issue', 'file', 'msg', 'keyword', 'priority', 'status':
        db.security.addPermissionToRole('Anonymous', 'View', cl)

    # Allow the anonymous user to use the "Show Unassigned" search.
    # It acts like "Show Open" if this permission is not available.
    # If you are running a tracker that does not allow read access for
    # anonymous, you should remove this entry as it can be used to perform
    # a username guessing attack against a roundup install.
    p = db.security.addPermission(name='Search', klass='user')
    db.security.addPermissionToRole ('Anonymous', p)

    # [OPTIONAL]
    # Allow anonymous users access to create or edit "issue" items (and the
    # related file and message items)
    #for cl in 'issue', 'file', 'msg':
    #   db.security.addPermissionToRole('Anonymous', 'Create', cl)
    #   db.security.addPermissionToRole('Anonymous', 'Edit', cl)

You can use `roundup-admin security` to verify the permissions defined in the schema. It also verifies that properties specified in permissions are valid for the class. This helps detect typos that can cause baffling permission issues.

### Automatic Permission Checks

Permissions are automatically checked when information is rendered through the web. This includes:

1. View checks for properties when being rendered via the `plain()` or similar methods. If the check fails, the text “[hidden]” will be displayed.
2. Edit checks for properties when the edit field is being rendered via the `field()` or similar methods. If the check fails, the property will be rendered via the `plain()` method (see point 1. for subsequent checking performed)
3. View checks are performed in index pages for each item being displayed such that if the user does not have permission, the row is not rendered.
4. View checks are performed at the top of item pages for the Item being displayed. If the user does not have permission, the text “You are not allowed to view this page.” will be displayed.
5. View checks are performed at the top of index pages for the Class being displayed. If the user does not have permission, the text “You are not allowed to view this page.” will be displayed.

### New User Roles

New users are assigned the Roles defined in the config file as:

- NEW_WEB_USER_ROLES
- NEW_EMAIL_USER_ROLES

The users may only edit their issues example shows customisation of these parameters.

### Changing Access Controls

You may alter the configuration variables to change the Role that new web or email users get, for example to not give them access to the web interface if they register through email.

You may use the `roundup-admin` “`security`” command to display the current Role and Permission configuration in your tracker.

#### Adding a new Permission

When adding a new Permission, you will need to:

1. add it to your tracker’s `schema.py` so it is created, using `security.addPermission`, for example:

       db.security.addPermission(name="View", klass='frozzle',
           description="User is allowed to access frozzles")

   will set up a new “View” permission on the Class “frozzle”.

2. enable it for the Roles that should have it (verify with “`roundup-admin security`”)

3. add it to the relevant HTML interface templates

4. add it to the appropriate xxxPermission methods on in your tracker interfaces module

The `addPermission` method takes a few optional parameters:

properties
  A sequence of property names that are the only properties to apply the new Permission to (eg. `... klass='user', properties=('name', 'email') ...`)
props_only

  A boolean value (set to false by default) that is a new feature in Roundup 1.6. A permission defined using:

  > `properties=('list', 'of', 'property', 'names')`

  is used to determine access for things other than just those properties. For example a check for View permission on the issue class or an issue item can use any View permission for the issue class even if that permission has a property list. This can be confusing and surprising as you would think that a permission including properties would be used only for determining the access permission for those properties.

  `roundup-admin security` will report invalid properties for the class. For example a permission with an invalid summary property is presented as:

      Allowed to see content of object regardless of spam status
         (View for "file": ('content', 'summary') only)

      **Invalid properties for file: ['summary']

  Setting `props_only=True` will make the permission valid only for those properties.

  If you use a lot of permissions with property checks, it can be difficult to change all of them. Calling the function:

  > db.security.set_props_only_default(True)

  at the top of `schema.py` will make every permission creation behave as though props_only was set to True. It is expected that the default of True will become the default in a future Roundup release.

check

  A function to be executed which returns boolean determining whether the Permission is allowed. If it returns True, the permission is allowed, if it returns False the permission is denied. The function can have one of two signatures:

      check(db, userid, itemid)

  or:

      check(db, userid, itemid, **ctx)

  where `db` is a handle on the open database, `userid` is the user attempting access and `itemid` is the specific item being accessed. If the second form is used the `ctx` dictionary is defined with the following values:

      ctx['property'] the name of the property being checked or None if
             it's a class check.

      ctx['classname'] the name of the class that is being checked
             (issue, query ....).

      ctx['permission'] the name of the permission (e.g. View, Edit...).

The second form is preferred as it makes it easier to implement more complex permission schemes. An example in upgrading.html shows the use of `ctx`.

#### Example Scenarios

See the examples section for longer examples of customisation.

anonymous access through the e-mail gateway
  Give the “anonymous” user the “Email Access”, (“Edit”, “issue”) and (“Create”, “msg”) Permissions but do not not give them the (“Create”, “user”) Permission. This means that when an unknown user sends email into the tracker, they’re automatically logged in as “anonymous”. Since they don’t have the (“Create”, “user”) Permission, they won’t be automatically registered, but since “anonymous” has permission to use the gateway, they’ll still be able to submit issues. Note that the Sender information - their email address - will not be available - they’re anonymous.
automatic registration of users in the e-mail gateway
  By giving the “anonymous” user the (“Register”, “user”) Permission, any unidentified user will automatically be registered with the tracker (with no password, so they won’t be able to log in through the web until an admin sets their password). By default new Roundup trackers don’t allow this as it opens them up to spam. It may be enabled by uncommenting the appropriate addPermissionToRole in your tracker’s `schema.py` file. The new user is given the Roles list defined in the “new_email_user_roles” config variable.
only developers may be assigned issues
  Create a new Permission called “Fixer” for the “issue” class. Create a new Role “Developer” which has that Permission, and assign that to the appropriate users. Filter the list of users available in the assignedto list to include only those users. Enforce the Permission with an auditor. See the example restricting the list of users that are assignable to a task.
only managers may sign off issues as complete

  Create a new Permission called “Closer” for the “issue” class. Create a new Role “Manager” which has that Permission, and assign that to the appropriate users. In your web interface, only display the “resolved” issue state option when the user has the “Closer” Permissions. Enforce the Permission with an auditor. This is very similar to the previous example, except that the web interface check would look like:

      <option tal:condition="python:request.user.hasPermission('Closer')"
              value="resolved">Resolved</option>

don’t give web access to users who register through email
  Create a new Role called “Email User” which has all the Permissions of the normal “User” Role minus the “Web Access” Permission. This will allow users to send in emails to the tracker, but not access the web interface.
let some users edit the details of all users

  Create a new Role called “User Admin” which has the Permission for editing users:

      db.security.addRole(name='User Admin', description='Managing users')
      p = db.security.getPermission('Edit', 'user')
      db.security.addPermissionToRole('User Admin', p)

  and assign the Role to the users who need the permission.

## Web Interface

- Repercussions of changing the tracker schema
- How requests are processed
- Roundup URL design
- Determining web context
- The “home” Context
- Serving static content
- Performing actions in web requests
- Protecting users from web application attacks
- Special form variables
- Default templates
- Implementing Modal Editing Using @template
- How the templates work
  - Templating engines
  - Basic Templating Actions
  - Templating Expressions
  - Template Macros
- Information available to templates
  - The context variable
    - Hyperdb class wrapper
    - Hyperdb item wrapper
    - Hyperdb property wrapper
  - The request variable
    - The form variable
  - The db variable
  - The templates variable
  - The repeat variable
  - The utils variable
    - Batching
  - Translations
- Displaying Properties
- Index Views
  - Index View Specifiers
- Searching Views
- Item Views
  - Editor Section
    - Form values
  - Spool Section
  - History Section
- Defining new web actions
  - Define the new action class
  - Register the action class
  - Use the new action
  - Actions may return content to the user
- 8-bit character set support in Web interface

The web interface is provided by the `roundup.cgi.client` module and is used by `roundup.cgi`, `roundup-server` and `ZRoundup` (`ZRoundup` is broken, until further notice). In all cases, we determine which tracker is being accessed (the first part of the URL path inside the scope of the CGI handler) and pass control on to the `roundup.cgi.client.Client` class - which handles the rest of the access through its `main()` method. This means that you can do pretty much anything you want as a web interface to your tracker.

### Repercussions of changing the tracker schema

If you choose to change the tracker schema you will need to ensure the web interface knows about it:

1. Index, item and search pages for the relevant classes may need to have properties added or removed,
2. The “page” template may require links to be changed, as might the “home” page’s content arguments.

### How requests are processed

The basic processing of a web request proceeds as follows:

1. figure out who we are, defaulting to the “anonymous” user
2. figure out what the request is for - we call this the “context”
3. handle any requested action (item edit, search, …)
4. render the template requested by the context, resulting in HTML output

In some situations, exceptions occur:

- HTTP Redirect (generally raised by an action)
    the URL to redirect to is the first argument of the exception.
- SendFile (generally raised by `determine_context`)
    here we serve up a FileClass “content” property
- SendStaticFile (generally raised by `determine_context`)
    here we serve up a file from the tracker “html” directory
- Unauthorised (generally raised by an action)
    here the action is cancelled, the request is rendered and an error message is displayed indicating that permission was not granted for the action to take place
- NotFound (raised wherever it needs to be)
    this exception percolates up to the CGI interface that called the client

### Roundup URL design

Each tracker has several hardcoded URLs. These three are equivalent and lead to the main tracker page:

1. `/`
2. `/index`
3. `/home`

The following prefix is used to access static resources:

4. `/@@file/`

Two additional url’s are used for the API’s. The REST api is accessed via:

5. `/rest/`

and the XMLRPC api is available at:

6. `/xmlrpc`

All other URLs depend on the classes configured in Roundup database. Each class receives two URLs - one for the class itself and another for specific items of that class. Example for class URL:

7. `/issue`

This is usually used to show listings of class items. The URL for for specific object of issue class with id 1 will look like:

8. `/issue1`

Note that a leading string of 0’s will be stripped from the id part of the object designator in the URL. E.G. `/issue001` is the same as `/issue1`. Similarly for `/file01` etc. However you should generate URL’s without the extra zeros.

### Determining web context

To determine the “context” of a request (what request is for), we look at the URL path after the tracker root and at `@template` request parameter. Typical URL paths look like:

1. `/tracker/issue`
2. `/tracker/issue1`
3. `/tracker/@@file/style.css`
4. `/cgi-bin/roundup.cgi/tracker/file1`
5. `/cgi-bin/roundup.cgi/tracker/file1/kitten.png`

where tracker root is `/tracker/` or `/cgi-bin/roundup.cgi/tracker/` We’re looking at “issue”, “issue1”, “@@file/style.css”, “file1” and “file1/kitten.png” in the cases above.

1. with is no path we are in the “home” context. See the “home” context below for details. “index” or “home” paths may also be used to switch into “home” context.
2. for paths starting with “@@file” the additional path entry (“style.css” in the example above) specifies the static file to be served from the tracker TEMPLATES directory (or STATIC_FILES, if configured). This is usually the tracker’s “html” directory. Internally this works by raising SendStaticFile exception.
3. if there is something in the path (as in example 1, “issue”), it identifies the tracker class to display.
4. if the path is an item designator (as in examples 2 and 4, “issue1” and “file1”), then we’re to display a specific item. Note.
5. if the path starts with an item designator and is longer than one entry (as in example 5, “file1/kitten.png”), then we’re assumed to be handling an item of a `FileClass`, and the extra path information gives the filename that the client is going to label the download with (i.e. “file1/kitten.png” is nicer to download than “file1”). This raises a `SendFile` exception.

Neither 2. or 5. use templates and stop before the template is determined. For other contexts the template used is specified by the `@template` variable, which defaults to:

- only classname supplied: “index”
- full item designator supplied: “item”

### The “home” Context

The “home” context is special because it allows you to add templated pages to your tracker that don’t rely on a class or item (ie. an issues list or specific issue).

Let’s say you wish to add frames to control the layout of your tracker’s interface. You’d probably have:

- A top-level frameset page. This page probably wouldn’t be templated, so it could be served as a static file (see serving static content)

- A sidebar frame that is templated. Let’s call this page “home.navigation.html” in your tracker’s “html” directory. To load that page up, you use the URL:

      <tracker url>/home?@template=navigation

### Serving static content

See the previous section determining web context where it describes `@@file` paths.

These files are served without any permission checks. Any user on the internet with the url can download the file.

This is rarely an issue since the html templates are just source code and much of it can be found in the Roundup repository. Other decoration (logos, stylesheets) are similarly not security sensitive. You can use the static_files setting in config.ini to eliminate access to the templates directory if desired.

If a file resolves to a symbolic link, it is not served.

### Performing actions in web requests

When a user requests a web page, they may optionally also request for an action to take place. As described in how requests are processed, the action is performed before the requested page is generated. Actions are triggered by using a `@action` CGI variable, where the value is one of:

login
  Attempt to log a user in.
logout
  Log the user out - make them “anonymous”.
register
  Attempt to create a new user based on the contents of the form and then log them in.
edit
  Perform an edit of an item in the database. There are some special form variables you may use. Also you can set the `__redirect_to` form variable to the URL that should be displayed after the edit is succesfully completed. If you wanted to edit a sequence of issues, users etc. this could be used to display the next item in the sequence to the user.
new
  Add a new item to the database. You may use the same special form variables as in the “edit” action. Also you can set the `__redirect_to` form variable to the URL that should be displayed after the new item is created. This is useful if you want to create another item rather than edit the newly created item.
retire
  Retire the item in the database.
editCSV
  Performs an edit of all of a class’ items in one go. See also the class.csv templating method which generates the CSV data to be edited, and the `'_generic.index'` template which uses both of these features.
search

  Mangle some of the form variables:

  - Set the form “:filter” variable based on the values of the filter variables - if they’re set to anything other than “dontcare” then add them to :filter.
  - Also handle the “:queryname” variable and save off the query to the user’s query list.

Each of the actions is implemented by a corresponding `*XxxAction*` (where “Xxx” is the name of the action) class in the `roundup.cgi.actions` module. These classes are registered with `roundup.cgi.client.Client`. If you need to define new actions, you may add them there (see defining new web actions).

Each action class also has a `*permission*` method which determines whether the action is permissible given the current user. The base permission checks for each action are:

login
  Determine whether the user has the “Web Access” Permission.
logout
  No permission checks are made.
register
  Determine whether the user has the (“Create”, “user”) Permission.
edit
  Determine whether the user has permission to edit this item. If we’re editing the “user” class, users are allowed to edit their own details - unless they try to edit the “roles” property, which requires the special Permission “Web Roles”.
new
  Determine whether the user has permission to create this item. No additional property checks are made. Additionally, new user items may be created if the user has the (“Create”, “user”) Permission.
editCSV
  Determine whether the user has permission to edit this class.
search
  Determine whether the user has permission to view this class.

### Protecting users from web application attacks

There is a class of attacks known as Cross Site Request Forgeries (CSRF). Malicious code running in the browser can making a request to Roundup while you are logged into Roundup. The malicious code piggy backs on your existing Roundup session to make changes without your knowledge. Roundup 1.6 has support for defending against this by analyzing the

- Referer,
- Origin, and
- Host or
- X-Forwarded-Host

HTTP headers. It compares the headers to the value of the web setting in the [tracker] section of the tracker’s `config.ini`.

Also a per form token (also called a nonce) can be enabled for the tracker using the `csrf_enforce_token` option in config.ini. When enabled, Roundup will validate a hidden form field called `@csrf`. If the validation fails (or the token is used more than once) the request is rejected. The `@csrf` input field is added automatically by calling the `submit` function/path. It can also be added manually by calling anti_csrf_nonce() directly. For example:

    <input name="@csrf" type="hidden"
       tal:attributes="value python:utils.anti_csrf_nonce(lifetime=10)">

By default a nonce lifetime is 2 weeks. However the lifetime (in minutes) can be set by passing a lifetime argument as shown above. The example above makes the nonce lifetime 10 minutes.

Search for @csrf in this document for more examples. There are more examples and information in `upgrading.txt`.

The token protects you because malicious code supplied by another site is unable to obtain the token. Thus many attempts they make to submit a request are rejected.

The protection on the xmlrpc interface is untested, but is based on a valid header check against the Roundup url and the presence of the `X-REQUESTED-WITH` header. Work to improve this is a future project after the 1.6 release.

The enforcement levels can be modified in `config.ini`. Refer to that file for details.

### Special form variables

Item properties and their values are edited with html FORM variables and their values. You can:

- Change the value of some property of the current item.
- Create a new item of any class, and edit the new item’s properties,
- Attach newly created items to a multilink property of the current item.
- Remove items from a multilink property of the current item.
- Specify that some properties are required for the edit operation to be successful.
- Redirect to a different page after creating a new item (new action only, not edit action). Usually you end up on the page for the created item.
- Set up user interface locale.

These operations will only take place if the form action (the `@action` variable) is “edit” or “new”.

In the following, <bracketed> values are variable, “@” may be either “:” or “@”, and other text “required” is fixed.

Two special form variables are used to specify user language preferences:

`@language`
  value may be locale name or `none`. If this variable is set to locale name, web interface language is changed to given value (provided that appropriate translation is available), the value is stored in the browser cookie and will be used for all following requests. If value is `none` the cookie is removed and the language is changed to the tracker default, set up in the tracker configuration or OS environment.
`@charset`
  value may be character set name or `none`. Character set name is stored in the browser cookie and sets output encoding for all HTML pages generated by Roundup. If value is `none` the cookie is removed and HTML output is reset to Roundup internal encoding (UTF-8).

Most properties are specified as form variables:

`<propname>`
  property on the current context item
`<designator>"@"<propname>`
  property on the indicated item (for editing related information)

Designators name a specific item of a class.

`<classname><N>`
  Name an existing item of class <classname>.
`<classname>"-"<N>`
  Name the <N>th new item of class <classname>. If the form submission is successful, a new item of <classname> is created. Within the submitted form, a particular designator of this form always refers to the same new item.

Once we have determined the “propname”, we look at it to see if it’s special:

`@required`

  The associated form value is a comma-separated list of property names that must be specified when the form is submitted for the edit operation to succeed.

  When the <designator> is missing, the properties are for the current context item. When <designator> is present, they are for the item specified by <designator>.

  The “@required” specifier must come before any of the properties it refers to are assigned in the form.

`@remove@<propname>=id(s)` or `@add@<propname>=id(s)`
  The “@add@” and “@remove@” edit actions apply only to Multilink properties. The form value must be a comma-separate list of keys for the class specified by the simple form variable. The listed items are added to (respectively, removed from) the specified property.
`@link@<propname>=<designator>`
  If the edit action is “@link@”, the simple form variable must specify a Link or Multilink property. The form value is a comma-separated list of designators. The item corresponding to each designator is linked to the property given by simple form variable.
None of the above (ie. just a simple form value)

  The value of the form variable is converted appropriately, depending on the type of the property.

  For a Link(‘klass’) property, the form value is a single key for ‘klass’, where the key field is specified in schema.py.

  For a Multilink(‘klass’) property, the form value is a comma-separated list of keys for ‘klass’, where the key field is specified in schema.py.

  Note that for simple-form-variables specifiying Link and Multilink properties, the linked-to class must have a key field.

  For a String() property specifying a filename, the file named by the form value is uploaded. This means we try to set additional properties “filename” and “type” (if they are valid for the class). Otherwise, the property is set to the form value.

  For Date(), Interval(), Boolean(), Integer() and Number() properties, the form value is converted to the appropriate value.

Any of the form variables may be prefixed with a classname or designator.

Setting the form variable: `__redirect_to=` to a url when @action=new redirects the user to the specified url after successfully creating the new item. This is useful if you want the user to create another item rather than edit the newly created item. Note that the url assigned to `__redirect_to` must be url encoded/quoted and be under the tracker’s base url. If the base_url uses http, you can set the url to https.

Two special form values are supported for backwards compatibility:

@note

  This is equivalent to:

      @link@messages=msg-1
      msg-1@content=value

  which is equivalent to the html:

      <textarea name="msg-1@content"></textarea>
      <input type="hidden" name="@link@messages" value="msg-1">

  except that in addition, the “author” and “date” properties of “msg-1” are set to the userid of the submitter, and the current time, respectively.

@file

  This is equivalent to:

      @link@files=file-1
      file-1@content=value

  by adding the HTML:

      <input type="file" name="file-1@content">
      <input type="hidden" name="@link@files" value="file-1">

  The String content value is handled as described above for file uploads.

If both the “@note” and “@file” form variables are specified, the action:

    msg-1@link@files=file-1

is also performed. This would be expressed in HTML with:

    <input type="hidden" name="msg-1@link@files" value="file-1">

We also check that FileClass items have a “content” property with actual content, otherwise we remove them from all_props before returning.

### Default templates

The default templates are html4 compliant. Support for xhtml is due to be phased out so leave the `html_version` configuration variable in `config.ini` as `'html'` instead of `'xhtml'`.

Most customisation of the web view can be done by modifying the templates in the tracker `'html'` directory. There are several types of files in there. The minimal template includes:

page.html
  This template usually defines the overall look of your tracker. When you view an issue, it appears inside this template. When you view an index, it also appears inside this template. This template defines a macro called “icing” which is used by almost all other templates as a coating for their content, using its “content” slot. It also defines the “head_title” and “body_title” slots to allow setting of the page title.
home.html
  the default page displayed when no other page is indicated by the user
home.classlist.html
  a special version of the default page that lists the classes in the tracker
classname.item.html
  displays an item of the classname class
classname.index.html
  displays a list of classname items
classname.search.html
  displays a search page for classname items
_generic.index.html
  used to display a list of items where there is no `*classname*.index` available
_generic.help.html
  used to display a “class help” page where there is no `*classname*.help`
user.register.html
  a special page just for the user class, that renders the registration page
style.css
  a static file that is served up as-is

The classic template has a number of additional templates.

Remember that you can create any template extension you want to, so if you just want to play around with the templating for new issues, you can copy the current “issue.item” template to “issue.test”, and then access the test template using the “@template” URL argument:

    http://your.tracker.example/tracker/issue?@template=test

and it won’t affect your users using the “issue.item” template.

You can also put templates into a subdirectory of the template directory. So if you specify:

    http://your.tracker.example/tracker/issue?@template=test/item

you will use the template at: `test/issue.item.html`. If that template doesn’t exit it will try to use `test/_generic.item.html`. If that template doesn’t exist it will return an error.

### Implementing Modal Editing Using @template

Many item templates allow you to edit the item. They contain code that renders edit boxes if the user has edit permissions. Otherwise the template will just display the item information.

In some cases you want to do a modal edit. The user has to take some action (click a button or follow a link) to shift from display mode to edit mode. When the changes are submitted, ending the edit mode, the user is returned to display mode.

Modal workflows usually slow things down and are not implemented by default templates. However for some workflows a modal edit is useful. For example a batch edit mode that allows the user to edit a number of issues all from one form could be implemented as a modal workflow of:

- search for issues to modify
- switch to edit mode and change values
- exit back to the results of the search

To implement the modal edit, assume you have an issue.edit.html template that implements an edit form. On the display page (a version of issue.item.html modified to only display information) add a link that calls the display url, but adds `@template=edit` to the link.

This will now display the edit page. On the edit page you want to add a hidden text field to your form named `@template` with the value: `item|edit`. When the form is submitted it is validated. If the form is correct the user will see the item rendered using the item template. If there is an error (validation failed) the item will be rendered using the edit template. The edit template that is rendered will display all the changes that the user made to the form before it was submitted. The user can correct the error and resubmit the changes until the form validates.

If the form failed to validate but the `@template` field had the value `item` the user would still see the error, but all of the data the user entered would be discarded. The user would have to redo all the edits again.

### How the templates work

#### Templating engines

Since version 1.4.20 Roundup supports two templating engines:

- the original Template Attribute Language (TAL) engine from Zope
- the standalone Chameleon templating engine. Chameleon is intended as a replacement for the original TAL engine, and supports the same syntax, but they are not 100% compatible. The major (and most likely the only) incompatibility is the default expression type being `python:` instead of `path:`. See also “Incompatibilities and differences” section of Chameleon documentation.

Version 1.5.0 added experimental support for the jinja2 templating language. You must install the jinja2 module in order to use it. The `jinja2` template supplied with Roundup has the templates rewritten to use `jinja2` rather than TAL. A number of trackers are running using `jinja2` templating so it is considered less experimental than Chameleon templating.

NOTE1: For historical reasons, examples given below assumes path expression as default expression type. With Chameleon you have to manually resolve the path expressions. A Chameleon-based, z3c.pt, that is fully compatible with the old TAL implementation, is planned to be included in a future release.

NOTE2: As of 1.4.20 Chameleon support is highly experimental and not recommended for production use.

#### Basic Templating Actions

Roundup’s templates consist of special attributes on the HTML tags. These attributes form the Template Attribute Language, or TAL. The basic TAL commands are:

tal:define=”variable expression; variable expression; …”

  Define a new variable that is local to this tag and its contents. For example:

      <html tal:define="title request/description">
       <head><title tal:content="title"></title></head>
      </html>

  In this example, the variable “title” is defined as the result of the expression “request/description”. The “tal:content” command inside the <html> tag may then use the “title” variable.

tal:condition=”expression”

  Only keep this tag and its contents if the expression is true. For example:

      <p tal:condition="python:request.user.hasPermission('View', 'issue')">
       Display some issue information.
      </p>

  In the example, the <p> tag and its contents are only displayed if the user has the “View” permission for issues. We consider the number zero, a blank string, an empty list, and the built-in variable nothing to be false values. Nearly every other value is true, including non-zero numbers, and strings with anything in them (even spaces!).

tal:repeat=”variable expression”

  Repeat this tag and its contents for each element of the sequence that the expression returns, defining a new local variable and a special “repeat” variable for each element. For example:

      <tr tal:repeat="u user/list">
       <td tal:content="u/id"></td>
       <td tal:content="u/username"></td>
       <td tal:content="u/realname"></td>
      </tr>

  The example would iterate over the sequence of users returned by “user/list” and define the local variable “u” for each entry. Using the repeat command creates a new variable called “repeat” which you may access to gather information about the iteration. See the section below on the repeat variable.

tal:replace=”expression”

  Replace this tag with the result of the expression. For example:

      <span tal:replace="request/user/realname" />

  The example would replace the <span> tag and its contents with the user’s realname. If the user’s realname was “Bruce”, then the resultant output would be “Bruce”.

tal:content=”expression”

  Replace the contents of this tag with the result of the expression. For example:

      <span tal:content="request/user/realname">user's name appears here
      </span>

  The example would replace the contents of the <span> tag with the user’s realname. If the user’s realname was “Bruce” then the resultant output would be “<span>Bruce</span>”.

tal:attributes=”attribute expression; attribute expression; …”

  Set attributes on this tag to the results of expressions. For example:

      <a tal:attributes="href string:user${request/user/id}">My Details</a>

  In the example, the “href” attribute of the <a> tag is set to the value of the “string:user${request/user/id}” expression, which will be something like “user123”.

tal:omit-tag=”expression”

  Remove this tag (but not its contents) if the expression is true. For example:

      <span tal:omit-tag="python:1">Hello, world!</span>

  would result in output of:

      Hello, world!

Note that the commands on a given tag are evaulated in the order above, so define comes before condition, and so on.

Additionally, you may include tags such as <tal:block>, which are removed from output. Its content is kept, but the tag itself is not (so don’t go using any “tal:attributes” commands on it). This is useful for making arbitrary blocks of HTML conditional or repeatable (very handy for repeating multiple table rows, which would otherwise require an illegal tag placement to effect the repeat).

#### Templating Expressions

Templating Expressions are covered by Template Attribute Language Expression Syntax, or TALES. The expressions you may use in the attribute values may be one of the following forms:

Path Expressions - eg. `item/status/checklist`

  These are object attribute / item accesses. Roughly speaking, the path `item/status/checklist` is broken into parts `item`, `status` and `checklist`. The `item` part is the root of the expression. We then look for a `status` attribute on `item`, or failing that, a `status` item (as in `item['status']`). If that fails, the path expression fails. When we get to the end, the object we’re left with is evaluated to get a string - if it is a method, it is called; if it is an object, it is stringified. Path expressions may have an optional `path:` prefix, but they are the default expression type, so it’s not necessary.

  If an expression evaluates to `default`, then the expression is “cancelled” - whatever HTML already exists in the template will remain (tag content in the case of `tal:content`, attributes in the case of `tal:attributes`).

  If an expression evaluates to `nothing` then the target of the expression is removed (tag content in the case of `tal:content`, attributes in the case of `tal:attributes` and the tag itself in the case of `tal:replace`).

  If an element in the path may not exist, then you can use the `|` operator in the expression to provide an alternative. So, the expression `request/form/foo/value | default` would simply leave the current HTML in place if the “foo” form variable doesn’t exist.

  You may use the python function `path`, as in `path("item/status")`, to embed path expressions in Python expressions.

String Expressions - eg. `string:hello ${user/name}`
  These expressions are simple string interpolations - though they can be just plain strings with no interpolation if you want. The expression in the `${ ... }` is just a path expression as above.
Python Expressions - eg. `python: 1+1`
  These expressions give the full power of Python. All the “root level” variables are available, so `python:item.status.checklist()` would be equivalent to `item/status/checklist`, assuming that `checklist` is a method.

Modifiers:

structure - eg. `structure python:msg.content.plain(hyperlink=1)`
  The result of expressions are normally escaped to be safe for HTML display (all “<”, “>” and “&” are turned into special entities). The `structure` expression modifier turns off this escaping - the result of the expression is now assumed to be HTML, which is passed to the web browser for rendering.
not: - eg. `not:python:1=1`
  This simply inverts the logical true/false value of another expression.

#### Template Macros

Macros are used in Roundup to save us from repeating the same common page stuctures over and over. The most common (and probably only) macro you’ll use is the “icing” macro defined in the “page” template.

Macros are generated and used inside your templates using special attributes similar to the basic templating actions. In this case, though, the attributes belong to the Macro Expansion Template Attribute Language, or METAL. The macro commands are:

metal:define-macro=”macro name”

  Define that the tag and its contents are now a macro that may be inserted into other templates using the use-macro command. For example:

      <html metal:define-macro="page">
       ...
      </html>

  defines a macro called “page” using the `<html>` tag and its contents. Once defined, macros are stored on the template they’re defined on in the `macros` attribute. You can access them later on through the `templates` variable, eg. the most common `templates/page/macros/icing` to access the “page” macro of the “page” template.

metal:use-macro=”path expression”

  Use a macro, which is identified by the path expression (see above). This will replace the current tag with the identified macro contents. For example:

      <tal:block metal:use-macro="templates/page/macros/icing">
       ...
      </tal:block>

      will replace the tag and its contents with the "page" macro of the
      "page" template.

metal:define-slot=”slot name” and metal:fill-slot=”slot name”

  To define dynamic parts of the macro, you define “slots” which may be filled when the macro is used with a use-macro command. For example, the `templates/page/macros/icing` macro defines a slot like so:

      <title metal:define-slot="head_title">title goes here</title>

  In your use-macro command, you may now use a fill-slot command like this:

      <title metal:fill-slot="head_title">My Title</title>

  where the tag that fills the slot completely replaces the one defined as the slot in the macro.

Note that you may not mix METAL and TAL commands on the same tag, but TAL commands may be used freely inside METAL-using tags (so your fill-slots tags may have all manner of TAL inside them).

### Information available to templates

This is implemented by `roundup.cgi.templating.RoundupPageTemplate`

The following variables are available to templates.

context
  The current context. This is either None, a hyperdb class wrapper or a hyperdb item wrapper
request

  Includes information about the current request, including:

  - the current index information (`filterspec`, `filter` args, `properties`, etc) parsed out of the form.
  - methods for easy filterspec link generation
  - “form” The current CGI form information as a mapping of form argument name to value (specifically a cgi.FieldStorage)
  - “env” the CGI environment variables
  - “base” the base URL for this instance
  - “user” a HTMLItem instance for the current user
  - “language” as determined by the browser or config
  - “classname” the current classname (possibly None)
  - “template” the current template (suffix, also possibly None)
config
  This variable holds all the values defined in the tracker config.ini file (eg. TRACKER_NAME, etc.)
db
  The current database, used to access arbitrary database items.
templates
  Access to all the tracker templates by name. Used mainly in use-macro commands.
utils
  This variable makes available some utility functions like batching.
nothing

  This is a special variable - if an expression evaluates to this, then the tag (in the case of a `tal:replace`), its contents (in the case of `tal:content`) or some attributes (in the case of `tal:attributes`) will not appear in the the output. So, for example:

      <span tal:attributes="class nothing">Hello, World!</span>

  would result in:

      <span>Hello, World!</span>

default

  Also a special variable - if an expression evaluates to this, then the existing HTML in the template will not be replaced or removed, it will remain. So:

      <span tal:replace="default">Hello, World!</span>

  would result in:

      <span>Hello, World!</span>

true, false
  Boolean constants that may be used in templating expressions instead of `python:1` and `python:0`.
i18n

  Internationalization service, providing two string translation methods:

  gettext (message)
    Return the localized translation of message
  ngettext (singular, plural, number)
    Like `gettext()`, but consider plural forms. If a translation is found, apply the plural formula to number, and return the resulting message (some languages have more than two plural forms). If no translation is found, return singular if number is 1; return plural otherwise.

#### The context variable

The context variable is one of three things based on the current context (see determining web context for how we figure this out):

1. if we’re looking at a “home” page, then it’s None
2. if we’re looking at a specific hyperdb class, it’s a hyperdb class wrapper.
3. if we’re looking at a specific hyperdb item, it’s a hyperdb item wrapper.

If the context is not None, we can access the properties of the class or item. The only real difference between cases 2 and 3 above are:

1. the properties may have a real value behind them, and this will appear if the property is displayed through `context/property` or `context/property/field`.
2. the context’s “id” property will be a false value in the second case, but a real, or true value in the third. Thus we can determine whether we’re looking at a real item from the hyperdb by testing “context/id”.

##### Hyperdb class wrapper

This is implemented by the `roundup.cgi.templating.HTMLClass` class.

This wrapper object provides access to a hyperdb class. It is used primarily in both index view and new item views, but it’s also usable anywhere else that you wish to access information about a class, or the items of a class, when you don’t have a specific item of that class in mind.

We allow access to properties. There will be no “id” property. The value accessed through the property will be the current value of the same name from the CGI form.

There are several methods available on these wrapper objects:

Method | Description
--- | ---
properties | return a hyperdb property wrapper for all of this class’s properties that are searchable by the user. You can use the argument cansearch=False to get all properties.
list | lists all of the active (not retired) items in the class.
csv | return the items of this class as a chunk of CSV text.
propnames | lists the names of the properties of this class.
filter | lists of items from this class, filtered and sorted. Two options are available for sorting: by the current request filterspec/filter/sort/group args by the “filterspec”, “sort” and “group” keyword args. “filterspec” is `{propname: value(s)}`. “sort” and “group” are an optionally empty list `[(dir, prop)]` where dir is ‘+’, ‘-’ or None and prop is a prop name or None. The propname in filterspec and prop in a sort/group spec may be transitive, i.e., it may contain properties of the form link.link.link.name. eg. All issues with a priority of “1” with messages added in the last week, sorted by activity date: `issue.filter(filterspec={"priority": "1", 'messages.creation' : '.-1w;'}, sort=[('activity', '+')])` Note that when searching for Link and Multilink values, the special value ‘-1’ searches for empty Link or Multilink values. For both, Links and Multilinks, multiple values given in a filter call are combined with ‘OR’ by default. For Multilinks a postfix expression syntax using negative ID numbers (as strings) as operators is supported. Each non-negative number (or ‘-1’) is pushed on an operand stack. A negative number pops the required number of arguments from the stack, applies the operator, and pushes the result. The following operators are supported: ‘-2’ stands for ‘NOT’ and takes one argument ‘-3’ stands for ‘AND’ and takes two arguments ‘-4’ stands for ‘OR’ and takes two arguments Note that this special handling of ID arguments is applied only when a negative number smaller than -1 is encountered as an ID in the filter call. Otherwise the implicit OR default applies. Examples of using Multilink expressions would be ‘1’, ‘2’, ‘-4’, ‘3’, ‘4’, ‘-4’, ‘-3’ would search for IDs (1 or 2) and (3 or 4) ‘-1’ ‘-2’ would search for all non-empty Multilinks
filter_sql | Only in SQL backends Lists the items that match the SQL provided. The SQL is a complete “select” statement. The SQL select must include the item id as the first column. This function does not filter out retired items, add on a where clause “__retired__ <> 1” if you don’t want retired nodes.
classhelp | display a link to a javascript popup containing this class’ “help” template. This generates a link to a popup window which displays the properties indicated by “properties” of the class named by “classname”. The “properties” should be a comma-separated list (eg. ‘id,name,description’). Properties defaults to all the properties of a class (excluding id, creator, created and activity). You may optionally override the “label” displayed, the “width”, the “height”, the number of items per page (“pagesize”) and the field on which the list is sorted (“sort”). With the “filter” arg it is possible to specify a filter for which items are supposed to be displayed. It has to be of the format “<field>=<values>;<field>=<values>;…”. The popup window will be resizable and scrollable. If the “property” arg is given, it’s passed through to the javascript help_window function. This allows updating of a property in the calling HTML page. If the “form” arg is given, it’s passed through to the javascript help_window function - it’s the name of the form the “property” belongs to.
submit | generate a submit button (and action and @csrf hidden elements)
renderWith | render this class with the given template.
history | returns ‘New node - no history’ :)
is_edit_ok | is the user allowed to Edit the current class?
is_view_ok | is the user allowed to View the current class?

Note that if you have a property of the same name as one of the above methods, you’ll need to access it using a python “item access” expression. For example:

    python:context['list']

will access the “list” property, rather than the list method.

##### Hyperdb item wrapper

This is implemented by the `roundup.cgi.templating.HTMLItem` class.

This wrapper object provides access to a hyperdb item.

We allow access to properties. There will be no “id” property. The value accessed through the property will be the current value of the same name from the CGI form.

There are several methods available on these wrapper objects:

Method | Description
--- | ---
submit | generate a submit button (and action and @csrf hidden elements)
journal | return the journal of the current item (not implemented)
history | render the journal of the current item as HTML. By default properties marked as “quiet” (see design documentation) are not shown unless the function is called with the showall=True parameter. Properties that are not Viewable to the user are not shown.
renderQueryForm | specific to the “query” class - render the search form for the query
hasPermission | specific to the “user” class - determine whether the user has a Permission. The signature is:
    hasPermission(self, permission, [classname=],
        [property=], [itemid=])
where the classname defaults to the current context.
hasRole | specific to the “user” class - determine whether the user has a Role. The signature is:
    hasRole(self, rolename)
is_edit_ok | is the user allowed to Edit the current item?
is_view_ok | is the user allowed to View the current item?
is_retired | is the item retired?
download_url | generate a url-quoted link for download of FileClass item contents (ie. file<id>/<name>)
copy_url | generate a url-quoted link for creating a copy of this item. By default, the copy will acquire all properties of the current item except for `messages` and `files`. This can be overridden by passing `exclude` argument which contains a list (or any iterable) of property names that shall not be copied. Database-driven properties like `id` or `activity` cannot be copied.

Note that if you have a property of the same name as one of the above methods, you’ll need to access it using a python “item access” expression. For example:

    python:context['journal']

will access the “journal” property, rather than the journal method.

##### Hyperdb property wrapper

This is implemented by subclasses of the `roundup.cgi.templating.HTMLProperty` class (`HTMLStringProperty`, `HTMLNumberProperty`, and so on).

This wrapper object provides access to a single property of a class. Its value may be either:

1. if accessed through a hyperdb item wrapper, then it’s a value from the hyperdb
2. if access through a hyperdb class wrapper, then it’s a value from the CGI form

The property wrapper has some useful attributes:

Attribute | Description
--- | ---
_name | the name of the property
_value | the value of the property if any - this is the actual value retrieved from the hyperdb for this property

There are several methods available on these wrapper objects:

Method | Description
--- | ---
  plain | render a “plain” representation of the property. This method may take two arguments: escape If true, escape the text so it is HTML safe (default: no). The reason this defaults to off is that text is usually escaped at a later stage by the TAL commands, unless the “structure” option is used in the template. The following `tal:content` expressions are all equivalent:
      "structure python:msg.content.plain(escape=1)"
      "python:msg.content.plain()"
      "msg/content/plain"
      "msg/content"
  Usually you’ll only want to use the escape option in a complex expression. hyperlink If true, turn URLs, email addresses and hyperdb item designators in the text into hyperlinks (default: no). Note that you’ll need to use the “structure” TAL option if you want to use this `tal:content` expression:
      "structure python:msg.content.plain(hyperlink=1)"
The text is automatically HTML-escaped before the hyperlinking transformation done in the plain() method.
hyperlinked | The same as msg.content.plain(hyperlink=1), but nicer:
    "structure msg/content/hyperlinked"
field | render an appropriate form edit field for the property - for most types this is a text entry box, but for Booleans it’s a tri-state yes/no/neither selection. This method may take some arguments: size Sets the width in characters of the edit field format (Date properties only) Sets the format of the date in the field - uses the same format string argument as supplied to the `pretty` method below. popcal (Date properties only) Include the Javascript-based popup calendar for date selection. Defaults to on.
stext | only on String properties - render the value of the property as StructuredText (requires the StructureText module to be installed separately)
multiline | only on String properties - render a multiline form edit field for the property
email | only on String properties - render the value of the property as an obscured email address
url_quote | only on String properties. It quotes any characters in the string so it is safe to use in a url. E.G. a space is replaced with %20.
confirm | only on Password properties - render a second form edit field for the property, used for confirmation that the user typed the password correctly. Generates a field with name “name:confirm”.
now | only on Date properties - return the current date as a new property
reldate | only on Date properties - render the interval between the date and now
local | only on Date properties - return this date as a new property with some timezone offset, for example:
    python:context.creation.local(10)
will render the date with a +10 hour offset.
pretty | Date properties - render the date as “dd Mon YYYY” (eg. “19 Mar 2004”). Takes an optional format argument, for example:
    python:context.activity.pretty('%Y-%m-%d')
Will format as “2004-03-19” instead. Interval properties - render the interval in a pretty format (eg. “yesterday”). The format arguments are those used in the standard `strftime` call (see the Python Library Reference: time module) Number properties - takes a printf style format argument (default: ‘%0.3f’) and formats the number accordingly. If the value can’t be converted, ‘’ is returned if the value is `None` otherwise it is converted to a string.
popcal | Generate a link to a popup calendar which may be used to edit the date field, for example:
    <span tal:replace="structure context/due/popcal" />
you still need to include the `field` for the property, so typically you’d have:
    <span tal:replace="structure context/due/field" />
    <span tal:replace="structure context/due/popcal" />
menu | only on Link and Multilink properties - render a form select list for this property. Takes a number of optional arguments size is used to limit the length of the list labels height is used to set the <select> tag’s “size” attribute showid includes the item ids in the list labels additional lists properties which should be included in the label sort_on indicates the property to sort the list on as (direction, (direction, property) where direction is ‘+’ or ‘-’. A single string with the direction prepended may be used. For example: (‘-’, ‘order’), ‘+name’. value gives a default value to preselect in the menu The remaining keyword arguments are used as conditions for filtering the items in the list - they’re passed as the “filterspec” argument to a Class.filter() call. For example:
    <span tal:replace="structure context/status/menu" />

    <span tal:replace="python:context.status.menu(order='+name",
                          value='chatting',
                          filterspec={'status': '1,2,3,4'}" />
sorted | only on Multilink properties - produce a list of the linked items sorted by some property, for example:
    python:context.files.sorted('creation')
Will list the files by upload date. While:
    python:context.files.sorted('creation', reverse=True)
Will list the files by upload date in reverse order from the prior example. If the property can be unset, you can use the `NoneFirst` parameter to sort the None/Unset values at the front or the end of the list. For example:
    python:context.files.sorted('creation', NoneFirst=True)
will sort files by creation date with files missing a creation date at the start of the list. The default for `NoneFirst` is False so these files will sort at the end by default. (Note creation date is never unset, but you get the idea.) If you combine NoneFirst with `reverse=True` the meaning of NoneFirst is inverted: True sorts None/unset at the end and False sorts at the beginning.
reverse | only on Multilink properties - produce a list of the linked items in reverse order
isset | returns True if the property has been set to a value

All of the above functions perform checks for permissions required to display or edit the data they are manipulating. The simplest case is editing an issue title. Including the expression:

    context/title/field

Will present the user with an edit field, if they have edit permission. If not, then they will be presented with a static display if they have view permission. If they don’t even have view permission, then an error message is raised, preventing the display of the page, indicating that they don’t have permission to view the information.

#### The request variable

This is implemented by the `roundup.cgi.templating.HTMLRequest` class.

The request variable is packed with information about the current request.

Variable | Holds
--- | ---
form | the CGI form as a cgi.FieldStorage
env | the CGI environment variables
base | the base URL for this tracker
user | a HTMLUser instance for this user
classname | the current classname (possibly None)
template | the current template (suffix, also possibly None)
form | the current CGI form variables in a FieldStorage

Index page specific variables (indexing arguments)

Variable | Holds
--- | ---
columns | dictionary of the columns to display in an index page
show | a convenience access to columns - request/show/colname will be true if the columns should be displayed, false otherwise
sort | index sort columns [(direction, column name)]
group | index grouping properties [(direction, column name)]
filter | properties to filter the index on
filterspec | values to filter the index on (property=value, eg `priority=1` or `messages.author=42`
search_text | text to perform a full-text search on for an index

There are several methods available on the request variable:

Method | Description
--- | ---
description | render a description of the request - handle for the page title
indexargs_form | render the current index args as form elements
indexargs_url | render the current index args as a URL
base_javascript | render some javascript that is used by other components of the templating
batch | run the current index args through a filter and return a list of items (see hyperdb item wrapper, and batching)

##### The form variable

The form variable is a bit special because it’s actually a python FieldStorage object. That means that you have two ways to access its contents. For example, to look up the CGI form value for the variable “name”, use the path expression:

    request/form/name/value

or the python expression:

    python:request.form['name'].value

Note the “item” access used in the python case, and also note the explicit “value” attribute we have to access. That’s because the form variables are stored as MiniFieldStorages. If there’s more than one “name” value in the form, then the above will break since `request/form/name` is actually a list of MiniFieldStorages. So it’s best to know beforehand what you’re dealing with.

#### The db variable

This is implemented by the `roundup.cgi.templating.HTMLDatabase` class.

Allows access to all hyperdb classes as attributes of this variable. If you want access to the “user” class, for example, you would use:

    db/user
    python:db.user

Also, the current id of the current user is available as `db.getuid()`. This isn’t so useful in templates (where you have `request/user`), but it can be useful in detectors or interfaces.

The access results in a hyperdb class wrapper.

#### The templates variable

This was implemented by the `roundup.cgi.templating.Templates` class before 1.4.20. In later versions it is the instance of appropriate template engine loader class.

This variable is used to access other templates in expressions and template macros. It doesn’t have any useful methods defined. The templates can be accessed using the following path expression:

    templates/name

or the python expression:

    templates[name]

where “name” is the name of the template you wish to access. The template has one useful attribute, namely “macros”. To access a specific macro (called “macro_name”), use the path expression:

    templates/name/macros/macro_name

or the python expression:

    templates[name].macros[macro_name]

#### The repeat variable

The repeat variable holds an entry for each active iteration. That is, if you have a `tal:repeat="user db/users"` command, then there will be a repeat variable entry called “user”. This may be accessed as either:

    repeat/user
    python:repeat['user']

The “user” entry has a number of methods available for information:

Method | Description
--- | ---
first | True if the current item is the first in the sequence.
last | True if the current item is the last in the sequence.
even | True if the current item is an even item in the sequence.
odd | True if the current item is an odd item in the sequence.
number | Current position in the sequence, starting from 1.
letter | Current position in the sequence as a letter, a through z, then aa through zz, and so on.
Letter | Same as letter(), except uppercase.
roman | Current position in the sequence as lowercase roman numerals.
Roman | Same as roman(), except uppercase.

#### The utils variable

This is implemented by the `roundup.cgi.templating.TemplatingUtils` class, which may be extended with additional methods by extensions.

Method | Description
--- | ---
Batch | return a batch object using the supplied list
url_quote | quote some text as safe for a URL (ie. space, %, …)
html_quote | quote some text as safe in HTML (ie. <, >, …)
html_calendar | renders an HTML calendar used by the `_generic.calendar.html` template (itself invoked by the popupCalendar DateHTMLProperty method
anti_csrf_nonce | returns the random noncue generated for this session

##### Batching

Use Batch to turn a list of items, or item ids of a given class, into a series of batches. Its usage is:

    python:utils.Batch(sequence, size, start, end=0, orphan=0,
    overlap=0)

or, to get the current index batch:

    request/batch

The parameters are:

Parameter | Usage
--- | ---
sequence | a list of HTMLItems
size | how big to make the sequence.
start | where to start (0-indexed) in the sequence.
end | where to end (0-indexed) in the sequence.
orphan | if the next batch would contain less items than this value, then it is combined with this batch
overlap | the number of items shared between adjacent batches

All of the parameters are assigned as attributes on the batch object. In addition, it has several more attributes:

Attribute | Description
--- | ---
start | indicates the start index of the batch. Unlike the argument, is a 1-based index (I know, lame)
first | indicates the start index of the batch as a 0-based index
length | the actual number of elements in the batch
sequence_length | the length of the original, unbatched, sequence.

And several methods:

Method | Description
--- | ---
previous | returns a new Batch with the previous batch settings
next | returns a new Batch with the next batch settings
propchanged | detect if the named property changed on the current item when compared to the last item

An example of batching:

    <table class="otherinfo">
     <tr><th colspan="4" class="header">Existing Keywords</th></tr>
     <tr tal:define="keywords db/keyword/list"
         tal:repeat="start python:range(0, len(keywords), 4)">
      <td tal:define="batch python:utils.Batch(keywords, 4, start)"
          tal:repeat="keyword batch" tal:content="keyword/name">
          keyword here</td>
     </tr>
    </table>

… which will produce a table with four columns containing the items of the “keyword” class (well, their “name” anyway).

#### Translations

Should you wish to enable multiple languages in template content that you create you’ll need to add new locale files in the tracker home under a `locale` directory. Use the translation instructions in the developer’s guide to create the locale files.

### Displaying Properties

Properties appear in the user interface in three contexts: in indices, in editors, and as search arguments. For each type of property, there are several display possibilities. For example, in an index view, a string property may just be printed as a plain string, but in an editor view, that property may be displayed in an editable field.

### Index Views

This is one of the class context views. It is also the default view for classes. The template used is “classname.index”.

#### Index View Specifiers

An index view specifier (URL fragment) looks like this (whitespace has been added for clarity):

    /issue?status=unread,in-progress,resolved&
        keyword=security,ui&
        @group=priority,-status&
        @sort=-activity&
        @filters=status,keyword&
        @columns=title,status,fixer

The index view is determined by two parts of the specifier: the layout part and the filter part. The layout part consists of the query parameters that begin with colons, and it determines the way that the properties of selected items are displayed. The filter part consists of all the other query parameters, and it determines the criteria by which items are selected for display. The filter part is interactively manipulated with the form widgets displayed in the filter section. The layout part is interactively manipulated by clicking on the column headings in the table.

The filter part selects the union of the sets of items with values matching any specified Link properties and the intersection of the sets of items with values matching any specified Multilink properties.

The example specifies an index of “issue” items. Only items with a “status” of either “unread” or “in-progress” or “resolved” are displayed, and only items with “keyword” values including both “security” and “ui” are displayed. The items are grouped by priority arranged in ascending order and in descending order by status; and within groups, sorted by activity, arranged in descending order. The filter section shows filters for the “status” and “keyword” properties, and the table includes columns for the “title”, “status”, and “fixer” properties.

Argument | Description
--- | ---
@sort | sort by prop name, optionally preceeded with ‘-’ to give descending or nothing for ascending sorting. Several properties can be specified delimited with comma. Internally a search-page using several sort properties may use @sort0, @sort1 etc. with option @sortdir0, @sortdir1 etc. for the direction of sorting (a non-empty value of sortdir0 specifies reverse order).
@group | group by prop name, optionally preceeded with ‘-’ or to sort in descending or nothing for ascending order. Several properties can be specified delimited with comma. Internally a search-page using several grouping properties may use @group0, @group1 etc. with option @groupdir0, @groupdir1 etc. for the direction of grouping (a non-empty value of groupdir0 specifies reverse order).
@columns | selects the columns that should be displayed. Default is all.
@filter | indicates which properties are being used in filtering. Default is none.
propname | selects the values the item properties given by propname must have (very basic search/filter).
@search_text | if supplied, performs a full-text search (message bodies, issue titles, etc)

### Searching Views

Note

if you add a new column to the `@columns` form variable potentials then you will need to add the column to the appropriate index views template so that it is actually displayed.

This is one of the class context views. The template used is typically “classname.search”. The form on this page should have “search” as its `@action` variable. The “search” action:

- sets up additional filtering, as well as performing indexed text searching
- sets the `@filter` variable correctly
- saves the query off if `@query_name` is set.

The search page should lay out any fields that you wish to allow the user to search on. If your schema contains a large number of properties, you should be wary of making all of those properties available for searching, as this can cause confusion. If the additional properties are Strings, consider having their value indexed, and then they will be searchable using the full text indexed search. This is both faster, and more useful for the end user.

If the search view does specify the “search” `@action`, then it may also provide an additional argument:

Argument | Description
--- | ---
@query_name | if supplied, the index parameters (including @search_text) will be saved off as a the query item and registered against the user’s queries property. Note that the classic template schema has this ability, but the minimal template schema does not.

### Item Views

The basic view of a hyperdb item is provided by the “classname.item” template. It generally has three sections; an “editor”, a “spool” and a “history” section.

#### Editor Section

The editor section is used to manipulate the item - it may be a static display if the user doesn’t have permission to edit the item.

Here’s an example of a basic editor template (this is the default “classic” template issue item edit form - from the “issue.item.html” template):

    <table class="form">
    <tr>
     <th>Title</th>
     <td colspan="3" tal:content="structure python:context.title.field(size=60)">title</td>
    </tr>

    <tr>
     <th>Priority</th>
     <td tal:content="structure context/priority/menu">priority</td>
     <th>Status</th>
     <td tal:content="structure context/status/menu">status</td>
    </tr>

    <tr>
     <th>Superseder</th>
     <td>
      <span tal:replace="structure python:context.superseder.field(showid=1, size=20)" />
      <span tal:replace="structure python:db.issue.classhelp('id,title')" />
      <span tal:condition="context/superseder">
       <br>View: <span tal:replace="structure python:context.superseder.link(showid=1)" />
      </span>
     </td>
     <th>Nosy List</th>
     <td>
      <span tal:replace="structure context/nosy/field" />
      <span tal:replace="structure python:db.user.classhelp('username,realname,address,phone')" />
     </td>
    </tr>

    <tr>
     <th>Assigned To</th>
     <td tal:content="structure context/assignedto/menu">
      assignedto menu
     </td>
     <td>&nbsp;</td>
     <td>&nbsp;</td>
    </tr>

    <tr>
     <th>Change Note</th>
     <td colspan="3">
      <textarea name=":note" wrap="hard" rows="5" cols="60"></textarea>
     </td>
    </tr>

    <tr>
     <th>File</th>
     <td colspan="3"><input type="file" name=":file" size="40"></td>
    </tr>

    <tr>
     <td>&nbsp;</td>
     <td colspan="3" tal:content="structure context/submit">
      submit button will go here
     </td>
    </tr>
    </table>

When a change is submitted, the system automatically generates a message describing the changed properties. As shown in the example, the editor template can use the “:note” and “:file” fields, which are added to the standard changenote message generated by Roundup.

##### Form values

We have a number of ways to pull properties out of the form in order to meet the various needs of:

1. editing the current item (perhaps an issue item)
2. editing information related to the current item (eg. messages or attached files)
3. creating new information to be linked to the current item (eg. time spent on an issue)

In the following, `<bracketed>` values are variable, “:” may be one of “:” or “@”, and other text (“required”) is fixed.

Properties are specified as form variables:

`<propname>`
  property on the current context item
`<designator>:<propname>`
  property on the indicated item (for editing related information)
`<classname>-<N>:<propname>`
  property on the Nth new item of classname (generally for creating new items to attach to the current item)

Once we have determined the “propname”, we check to see if it is one of the special form values:

`@required`
  The named property values must be supplied or a ValueError will be raised.
`@remove@<propname>=id(s)`
  The ids will be removed from the multilink property.
`:add:<propname>=id(s)`
  The ids will be added to the multilink property.
`:link:<propname>=<designator>`
  Used to add a link to new items created during edit. These are collected and returned in `all_links`. This will result in an additional linking operation (either Link set or Multilink append) after the edit/create is done using `all_props` in `_editnodes`. The <propname> on the current item will be set/appended the id of the newly created item of class <designator> (where <designator> must be <classname>-<N>).

Any of the form variables may be prefixed with a classname or designator.

Two special form values are supported for backwards compatibility:

`:note`
  create a message (with content, author and date), linked to the context item. This is ALWAYS designated “msg-1”.
`:file`
  create a file, attached to the current item and any message created by :note. This is ALWAYS designated “file-1”.

#### Spool Section

The spool section lists related information like the messages and files of an issue.

TODO

#### History Section

The final section displayed is the history of the item - its database journal. This is generally generated with the template:

    <tal:block tal:replace="structure context/history" />

or:

    <tal:block
        tal:replace="structure python:context.history(showall=True)" />

if you want to show history entries for quiet properties.

To be done:

The actual history entries of the item may be accessed for manual templating through the “journal” method of the item:

    <tal:block tal:repeat="entry context/journal">
     a journal entry
    </tal:block>

where each journal entry is an HTMLJournalEntry.

### Defining new web actions

You may define new actions to be triggered by the `@action` form variable. These are added to the tracker `extensions` directory and registered using `instance.registerAction`.

All the existing Actions are defined in `roundup.cgi.actions`.

Adding action classes takes three steps; first you define the new action class, then you register the action class with the cgi interface so it may be triggered by the `@action` form variable. Finally you use the new action in your HTML form.

See setting up a “wizard” (or “druid”) for controlled adding of issues for an example.

#### Define the new action class

Create a new action class in your tracker’s `extensions` directory, for example `myaction.py`:

    from roundup.cgi.actions import Action

    class MyAction(Action):
        def handle(self):
            ''' Perform some action. No return value is required.
            '''

The self.client attribute is an instance of `roundup.cgi.client.Client`. See the docstring of that class for details of what it can do.

The method will typically check the `self.form` variable’s contents. It may then:

- add information to `self.client._ok_message` or `self.client._error_message` (by using `self.client.add_ok_message` or `self.client.add_error_message`, respectively)
- change the `self.client.template` variable to alter what the user will see next
- raise Unauthorised, SendStaticFile, SendFile, NotFound or Redirect exceptions (import them from roundup.cgi.exceptions)

#### Register the action class

The class is now written, but isn’t available to the user until you register it with the following code appended to your `myaction.py` file:

    def init(instance):
        instance.registerAction('myaction', myActionClass)

This maps the action name “myaction” to the action class we defined.

#### Use the new action

In your HTML form, add a hidden form element like so:

    <input type="hidden" name="@action" value="myaction">

where “myaction” is the name you registered in the previous step.

#### Actions may return content to the user

Actions generally perform some database manipulation and then pass control on to the rendering of a template in the current context (see Determining web context for how that works.) Some actions will want to generate the actual content returned to the user. Action methods may return their own content string to be displayed to the user, overriding the templating step. In this situation, we assume that the content is HTML by default. You may override the content type indicated to the user by calling `setHeader`:

    self.client.setHeader('Content-Type', 'text/csv')

This example indicates that the value sent back to the user is actually comma-separated value content (eg. something to be loaded into a spreadsheet or database).

### 8-bit character set support in Web interface

The web interface uses UTF-8 default. It may be overridden in both forms and a browser cookie.

- In forms, use the `@charset` variable.
- To use the cookie override, have the `roundup_charset` cookie set.

In both cases, the value is a valid charset name (eg. `utf-8` or `kio8-r`).

Inside Roundup, all strings are stored and processed in utf-8. Unfortunately, some older browsers do not work properly with utf-8-encoded pages (e.g. Netscape Navigator 4 displays wrong characters in form fields). This version allows one to change the character set for http transfers. To do so, you may add the following code to your `page.html` template:

    <tal:block define="uri string:${request/base}${request/env/PATH_INFO}">
     <a tal:attributes="href python:request.indexargs_url(uri,
      {'@charset':'utf-8'})">utf-8</a>
     <a tal:attributes="href python:request.indexargs_url(uri,
      {'@charset':'koi8-r'})">koi8-r</a>
    </tal:block>

(substitute `koi8-r` with appropriate charset for your language). Charset preference is kept in the browser cookie `roundup_charset`.

`meta http-equiv` lines added to the tracker templates in version 0.6.0 should be changed to include actual character set name:

    <meta http-equiv="Content-Type"
     tal:attributes="content string:text/html;; charset=${request/client/charset}"
    />

The charset is also sent in the http header.

## Debugging Trackers

There are three switches in tracker configs that turn on debugging in Roundup:

1. web :: debug
2. mail :: debug
3. logging :: level

See the config.ini file or the tracker configuration section for more information.

Additionally, the `roundup-server.py` script has its own debugging mode in which it reloads edited templates immediately when they are changed, rather than requiring a web server restart.

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