TWiki Meta Data
Topic data not editable from main freeform text box, stored in name/value META variable pairs
Overview
TWikiMetaData uses
META variables to store topic data that's separate from the main free-form content. This includes program-generated info like
FileAttachment data, and user-defined
Form Template info.
Meta Data Syntax
- Format is the same as in TWikiVariables, except all fields have a key.
- %META:<type>{key1="value1" [key2="value2" [...]]}%
- Order of fields within the meta variables is not defined, except that if there is a field with key
name, this appears first for easier searching (note the order of the variables themselves is defined).
- Each meta variable is on one line.
-
\n (new line) is represented in values by %_N_ and " (double-quotes) by %_Q_%.
Example of Format
%<nop>META:TOPICINFO{version="1.6" date="976762663" author="PeterThoeny" format="1.0"}%
text of the topic
%<nop>META:TOPICMOVED{from="Codev.OldName" to="CoDev.NewName"
by="JohnTalintyre" date="976762680"}%
%<nop>META:TOPICPARENT{name="NavigationByTopicContext"}%
%<nop>META:FILEATTACHMENT{name="Sample.txt" version="1.3" ... }%
%<nop>META:FILEATTACHMENT{name="Smile.gif" version="1.1" ... }%
%<nop>META:FORM{name="WebFormTemplate"}%
%<nop>META:FIELD{name="OperatingSystem" value="OsWin"}%
%<nop>META:FIELD{name="TopicClassification" value="PublicFAQ"}%
Specifications
The current version of Meta Data is 1.0, with support for the following variables.
TOPICINFO
| Key |
Comment |
| format |
Format of this topic, will be used for automatic format conversion |
| date |
integer, unx time, seconds since start 1970 |
| author |
last to change topic, is the REMOTE_USER |
| version |
Same as RCS version |
TOPICMOVED
This is optional, exists if topic has ever been moved. If a topic is moved more than once, only the most recent TOPICMOVED meta variable 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"}%
| Key |
Comment |
| from |
Full name i.e. web.topic |
| to |
Full name i.e. web.topic |
| by |
Who did it, is the REMOTE_USER, not WikiName |
| date |
integer, unx time, seconds since start 1970 |
Notes:
- at present version number is not supported directly, it can be inferred from the RCS history.
- there is only one META:TOPICMOVED in a topic, older move information can be found in the RCS history.
TOPICPARENT
| Key |
Comment |
| name |
The topic from which this was created, WebHome if done from Go, othewise topic where ? or form used. Normally just topic, but is full web.topic format if parent is in a different Web. Renaming a Web will then only break a few of these references or they can be scanned and fixed. |
FILEATTACHMENT
| Key |
Comment |
| name |
Name of file, no path. Must be unique within topic |
| version |
Same as RCS revision |
| path |
Full path file was loaded from |
| size |
In bytes |
| date |
integer, unx time, seconds since start 1970 |
| user |
the REMOTE_USER, not WikiName |
| comment |
As supplied when file uploaded |
| attr |
h if hidden, optional |
Extra fields that are added if an attachment is moved:
| movedfrom |
full topic name - web.topic |
| movedby |
the REMOTE_USER, not WikiName |
| movedto |
full topic name - web.topic |
| moveddate |
integer, unx time, seconds since start 1970 |
FORM
| Key |
Comment |
| name |
A topic name - the topic is a Form Template. Can optionally include the web name i.e. web.topic, but doesn't normally |
FIELD
Should only be present if there is a FORM entry. Note that this data is used when viewing a topic, the form template definition is not read.
| Key |
Name |
| name |
Ties to entry in Form Template, is title with all bar alphanumerics and . removed |
| title |
Full text from Form Template |
| value |
Value user has supplied via form |
Recommended Sequence
There is no absolute need for Meta Data variables to be listed in a specific order within a topic, but it makes sense to do so 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:
- TOPICINFO
-
text of topic
- TOPICMOVED (optional)
- TOPICPARENT (optional)
- FILEATTACHMENT (0 or more entries)
- FORM (optional)
- FIELD (0 or more entries; FORM required)
Viewing Meta Data in Page Source
When viewing a topic the
Raw Text link can be clicked to show the text of a topic (ie: 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% variable. This is mostly used in the
view,
preview and
edit scripts.
Current support covers:
| Variable usage: |
Comment: |
| %META{"form"}% |
Show form data, see Form Templates |
| %META{"attachments"}% |
Show attachments, exclude hidden |
| Options for Attachments: |
|
| all="on" |
Show ALL attachments (including hidden) |
| %META{"moved"}% |
Details of any topic moves |
| %META{"parent [options]"}% |
Show topic parent |
| Options for parent: |
|
| dontrecurse="on" |
By default recurses up tree, at some cost |
| prefix="..." |
Prefix for parents, only if there are parents; default "" |
| suffix="..." |
Suffix, only appears if there are parents; default "" |
| seperator="..." |
Separator between parents, default is " > " |
- Future Development: There are numerous development directions and specific features to consider. A couple of obvious possibilities:
- Rendering to formats other than tables: bullet lists, formatted body text;
- Specifying templates to be used for rendering.
Known Issues
At present, there is no Meta Data support for Plugins. However, the format is readily extendable and the
Meta.pm code that supports the format needs only minor alteration.
--
JohnTalintyre - 29 Aug 2001