path: root/TWiki/MetaDataDefinition.mdwn

## <a name="Meta_Data_Definition"> Meta Data Definition </a>

See [[MetaDataRendering]] for display of meta data

Current version: **1\.0**

Table of contents: %TOC%

### <a name="Example_of_format"> Example of format </a>

<pre>
%<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"}%
</nop></nop></nop></nop></nop></nop></nop></nop></pre>

### <a name="General_notes"> General notes </a>

* Format is as for %TWIKIWEB%.TWikiVariables, except all fields have a key.
  * %META:&lt;type&gt;\{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' is represented in values by <code>**%\_N\_**</code> and '"' by <code>**%\_Q\_%**</code>

### <a name="Logical_order"> Logical order </a>

There no absolute need for meta data to be in a specific order, however, it does for the following reasons:

* Keep (form) fields in the order they are defined
* Allow diff command to give output in a logically sensible order

These could be done in other ways, but this adds complexity

* Order fields - definition could be read on each rendering (expensive)
* Diff - render data before doing diff, has something to offer, but not likely to be available for next TWiki release

So the order is:

* TOPICINFO
* text of topic
* TOPICMOVED - optional
* TOPICPARENT - optional
* FILEATTACHMENT - 0 or more entries
* FORM - optional
* FIELD - 0 or more entries (FORM required)

### <a name="Specification"> Specification </a>

#### <a name="TOPICINFO"> </a> TOPICINFO

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th align="center" bgcolor="#99CCCC"><strong>Key</strong></th>
    <th align="center" bgcolor="#99CCCC"><strong>Comment</strong></th>
  </tr>
  <tr>
    <td> version </td>
    <td> Same as RCS version </td>
  </tr>
  <tr>
    <td> date </td>
    <td> integer, unx time, seconds since start 1970 </td>
  </tr>
  <tr>
    <td> author </td>
    <td> last to change topic, is the REMOTE_USER </td>
  </tr>
  <tr>
    <td> format </td>
    <td> Format of this topic, will be used for automatic format conversion </td>
  </tr>
</table>

#### <a name="TOPICMOVED"> </a> 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"\}%

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th align="center" bgcolor="#99CCCC"><strong>Key</strong></th>
    <th align="center" bgcolor="#99CCCC"><strong>Comment</strong></th>
  </tr>
  <tr>
    <td> from </td>
    <td> Full name i.e. web.topic </td>
  </tr>
  <tr>
    <td> to </td>
    <td> Full name i.e. web.topic </td>
  </tr>
  <tr>
    <td> by </td>
    <td> Who did it, is the REMOTE_USER, not <nop>WikiName </nop></td>
  </tr>
  <tr>
    <td> date </td>
    <td> integer, unx time, seconds since start 1970 </td>
  </tr>
</table>

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.

#### <a name="TOPICPARENT"> </a> TOPICPARENT

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong>Key</strong></th>
    <th bgcolor="#99CCCC"><strong>Comment</strong></th>
  </tr>
  <tr>
    <td> name </td>
    <td> The topic from which this was created, <span style="background:"><font color="">Web Home</font></span><a href="http://LOCATION/WebHome">?</a> if done from <code>Go</code>, othewise topic where <code>?</code> 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. </td>
  </tr>
</table>

#### <a name="FILEATTACHMENT"> </a> FILEATTACHMENT

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong>Key</strong></th>
    <th bgcolor="#99CCCC"><strong>Comment</strong></th>
  </tr>
  <tr>
    <td> name </td>
    <td> Name of file, no path. Must be unique within topic </td>
  </tr>
  <tr>
    <td> version </td>
    <td> Same as RCS revision </td>
  </tr>
  <tr>
    <td> path </td>
    <td> Full path file was loaded from </td>
  </tr>
  <tr>
    <td> size </td>
    <td> In bytes </td>
  </tr>
  <tr>
    <td> date </td>
    <td> integer, unx time, seconds since start 1970 </td>
  </tr>
  <tr>
    <td> user </td>
    <td> the REMOTE_USER, not <nop>WikiName </nop></td>
  </tr>
  <tr>
    <td> comment </td>
    <td> As supplied when file uploaded </td>
  </tr>
  <tr>
    <td> attr </td>
    <td><code>h</code> if hidden, optional </td>
  </tr>
</table>

Extra field that are added if an attachment is moved:

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <td> movedfrom </td>
    <td> full topic name - web.topic </td>
  </tr>
  <tr>
    <td> movedby </td>
    <td> the REMOTE_USER, not <nop>WikiName </nop></td>
  </tr>
  <tr>
    <td> movedto </td>
    <td> full topic name - web.topic </td>
  </tr>
  <tr>
    <td> moveddate </td>
    <td> integer, unx time, seconds since start 1970 </td>
  </tr>
</table>

#### <a name="FORM"> </a> FORM

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong>Key</strong></th>
    <th bgcolor="#99CCCC"><strong>Comment</strong></th>
  </tr>
  <tr>
    <td> name </td>
    <td> A topic name - the topic is a <span style="background:"><font color="">TWiki Form Template</font></span><a href="http://LOCATION/TWikiFormTemplate">?</a>. Can optionally include the web name i.e. web.topic, but doesn't normally </td>
  </tr>
</table>

#### <a name="FIELD"> </a> 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.

<table border="1" cellpadding="1" cellspacing="0">
  <tr>
    <th bgcolor="#99CCCC"><strong>Key</strong></th>
    <th bgcolor="#99CCCC"><strong>Name</strong></th>
  </tr>
  <tr>
    <td> name </td>
    <td> Ties to entry in <span style="background:"><font color="">TWiki Form Template</font></span><a href="http://LOCATION/TWikiFormTemplate">?</a>, is title with all bar alphanumerics and . removed </td>
  </tr>
  <tr>
    <td> title </td>
    <td> Full text from <span style="background:"><font color="">TWiki Form Template</font></span><a href="http://LOCATION/TWikiFormTemplate">?</a></td>
  </tr>
  <tr>
    <td> value </td>
    <td> Value user has supplied via form </td>
  </tr>
</table>

### <a name="Viewing_meta_data"> Viewing meta data </a>

When viewing a topic the `Raw Text` link can be clicked to show the text of a topic (i.e. as is seen when editing). This is done by adding `raw=on` to URL. `raw=debug` shows the meta data as well as the topic data e.g. [for this topic](%SCRIPTURLPATH%/view%SCRIPTSUFFIX%/%WEB%/%TOPIC%?raw=debug)

### <a name="Other"> Other </a>

There is currently no support for meta data for Plugins. However, the format is readily extendable and the `Meta.pm` code that supports the format only needs minor alteration.

-- [[Main/JohnTalintyre]] - 16 Aug 2001 <br />