Meta data

Additional topic data, program-generated or from DataForms, is stored embedded in the topic text using META: tags

Overview

By default, topics are stored in files on disk, in a really simple and obvious directory structure. The big advantage of this approach is that it makes it really easy to manipulate topics from outside, and is also very safe; there are no complex binary indexes to maintain, and moving a topic from one installation to another is as simple as copying a couple of text files.

To keep eveything together in one place, meta-data (program-generated or from DataForms) is embedded directly in topics. It does this using META: tags.

META: data includes program-generated info like FileAttachment, topic movement data and user-defined information from DataForms.

Meta data syntax

• Format is the same as in macros, except all fields have a key.
  • %META:<type>{key1="value1" key2="value2" ...}%

• Order of fields within the meta-data is not defined, except that if there is a field with key name, this appears first for easier searching (note the order of the data themselves is defined).

• Each meta-datum is on one line.

• Values in meta-data are URL encoded so that characters such as \n can be stored.

Example of Format

%META:TOPICINFO{version="1.6" date="976762663" author="LastEditorWikiName" format="1.0"}%
   text of the topic
%META:TOPICMOVED{from="Codev.OldName" to="Codev.NewName"
   by="TopicMoverWikiName" date="976762680"}%
%META:TOPICPARENT{name="NavigationByTopicContext"}%
%META:FILEATTACHMENT{name="Sample.txt" version="1.3" ... }%
%META:FILEATTACHMENT{name="Smile.gif" version="1.1" ... }%
%META:FORM{name="WebFormTemplate"}%
%META:FIELD{name="OperatingSystem" value="OsWin"}%
%META:FIELD{name="TopicClassification" value="PublicFAQ"}%

Meta data specifications

The current version of Meta Data is 1.0, with support for the following syntax.

META:TOPICINFO

META:TOPICMOVED

This is optional, exists if topic has ever been moved. If a topic is moved more than once, only the most recent META:TOPICMOVED meta datum exists in the topic, older ones are to be found in the rcs history.

%META:TOPICMOVED{from="Codev.OldName" to="Codev.NewName" by="talintj" date="976762680"}%

Notes:

• at present version number is not supported directly, it can be inferred from the SVN history.
• there is only one META:TOPICMOVED in a topic, older move information can be found in the SVN history.

META:TOPICPARENT

META:FILEATTACHMENT

Extra fields that are added if an attachment is moved:

META:FORM

META:FIELD

Should only be present if there is a META:FORM entry. Note that this data is used when viewing a topic; the form definition is not read.

Recommended sequence

There is no absolute need for Meta data to be listed in a specific order within a topic, but it makes sense to do so for a couple of good reasons:

• form fields remain in the order they are defined
• the diff function output appears in a logical order

The recommended sequence is:

• META:TOPICINFO
• META:TOPICPARENT (optional)
• text of topic
• META:TOPICMOVED (optional)
• META:FILEATTACHMENT (0 or more entries)
• META:FORM (optional)
• META:FIELD (0 or more entries; FORM required)

Viewing meta data in page source

When viewing a topic the [View raw text] link can be clicked to show the text of a topic (i.e., as seen when editing). This is done by adding raw=on to URL. raw=debug shows the meta data as well as the topic data, ex: debug view for this topic

Rendering meta data

Meta data is rendered with the %META% macro. This is mostly used in the view, preview and edit scripts.

You can render form fields in topic text by using the FORMFIELD macro. Example:
%FORMFIELD{"TopicClassification"}%
For details, see VarFORMFIELD.

Current support covers:

SEARCH can also be used to render meta data, see examples in FormattedSearch and SearchPatternCookbook.

Related Topics: DeveloperDocumentationCategory, UserDocumentationCategory