Wiki Processors

Processors are WikiMacros designed to provide alternative markup formats for the Trac Wiki engine. Processors can be thought of as macro functions to process user-edited text.

The wiki engine uses processors to allow using Restructured Text and raw HTML in any wiki text throughout Trac.

Using Processors

To use a processor on a block of text, use a wiki blockquote, selecting a processor by name using ‘hashbang notation’ (#!), familiar to most UNIX users from scripts.

Example 1 (inserting raw HTML in a wiki text): 

{{{
#!html
<h1 style="color: orange">This is raw HTML</h1>
}}}

Results in:

This is raw HTML

Example 2 (inserting Restructured Text in wiki text): 

{{{
#!rst
A header
--------
This is some **text** with a footnote [*]_.
.. [*] This is the footnote.
}}}

Results in:

Error: Failed to load processor rst:
Docutils >= 0.3.3 not found

#!rst
A header
--------
This is some **text** with a footnote [*]_.
.. [*] This is the footnote.

Example 3 (inserting a block of C source code in wiki text): 

{{{
#!c
int main(int argc, char *argv[])
{
  printf("Hello Worldn");
  return 0;
}
}}}

Results in: 

int main(int argc, char *argv[])
{
  printf("Hello Worldn");
  return 0;
}

Available Processors

The following processors are included in the Trac distribution:

  • html — Insert custom HTML in a wiki page. See WikiHtml.
  • rst — Trac support for Restructured Text. See WikiRestructuredText.
  • textile — Initial support as of aug 2, 2004. See ticket 593 and Textile.

Source Code Support

Trac includes processors to provide inline syntax highlighting for these languages:

  • c — C
  • cpp — C++
  • python — Python
  • perl — Perl
  • ruby — Ruby
  • php — PHP
  • asp — ASP
  • sql — SQL
  • xml — XML

Note: Trac relies on external software packages for syntax coloring. See TracSyntaxColoring for more info.

By using the mime-type as processor, it is posible to syntax-highlight the same languages that are supported when browsing source code. (The list of mime-types can be found in Mimeview.py).

For example, you can write: 

{{{
#!text/html
<h1>text</h1>
}}}

The result will be syntax highlighted html code. The same is valid for all other mime types supported.

For more processor macros developed and/or contributed by users, visit the macro bazaar:

http://projects.edgewall.com/trac/wiki/MacroBazaar

Advanced Topics: Developing Processor Macros

Developing processors is no different than WikiMacros. In fact they work the same way, only the usage syntax differs. See WikiMacros for more information.

Example: (Restructured Text Processor): 

from docutils.core import publish_string
def execute(hdf, text, env):
    html = publish_string(text, writer_name = 'html')
    return html[html.find('<body>')+6:html.find('</body>')].strip()

See also : WikiMacros, WikiHtml, WikiRestructuredText, TracSyntaxColoring, WikiFormatting, TracGuide