Filters

Filters allow for the for the automatic transformation of entered text into different, often more complex forms. For example the titles of Resources can automatically become hyperlinks that take you to the relevant resource, URLs pointing to mp3 files can become Flash controls embedded in the webpage that let you pause and rewind the audio. The possibilities are endless and there are a number of standard filters included with Moodle and many more specialized filters contributed by the community.

Filters administration screen

Template:Moodle 1.6 Cache Controls

Text cache lifetime
Filter uploaded files
Filter match once per page
Filter match once per text
Filter all strings

Algebra

This filter will convert algebra code into GIF images. It requires the tex filter to be installed (see below).

Glossary auto-linking

As the name suggests, this filter enables automatic linking of glossary entries. In addition to this filter, individual glossary entries should have the "This entry should be automatically linked" box checked.

It's possible to fine-tune text filtering by adding the following lines from config-dist.php to config.php and removing the //.

// Enabling this will make most text-based filters only match the first time
// a phrase occurs in a given text.  Otherwise all are matched.
//      $CFG->filtermatchonepertext = true;

Multimedia plugins

The Multimedia plugins filter looks for links to various media and replaces them with a proper plugin.

Multi-language content

This filter enables resources to be created in multiple languages. It looks for <lang> tags which indicate that a text contains multiple languages. Then it selects and outputs the best language for the current user. The language of the resource will change when the user changes their selected Moodle language.

To use this feature first create your contents in multiple languages (in the same resource). Then enclose each language block in the following tags:

     <lang lang="XX">your_content_here</lang>
     <lang lang="YY">your_content_in_other_language_here</lang>

TeX notation

The TeX notation filter converts TeX code into GIF images. It requires a binary program called MimeTeX - versions for Linux (glib2.3), Windows and Mac OS X are included.

Tidy

The tidy filter checks whether HTML code is XHTML compliant, tidying where necessary. To make this filter work you need to have PHP compiled. The discussion Tidy Filter for Moodle 1.5 contains more details.

Word censorship

Template:Moodle 1.6

Word censorship in 1.6

To enable word censorship in 1.5, Template:Moodle 1.5

Activate the word censorship filter
Edit config.php in in the root folder
Under // 7. OTHER MISCELLANEOUS SETTINGS add the line

$CFG->textfilter1 = 'filter/censor/filter.php';

Edit lang/xx/censor.php, adding any words you wish to ban
Type some bad words in the HTML editor, as a test. After saving your post, all bad words will be blacked out.

Non-standard filters

Jmol - for interactive 3D viewing of molecular structures
Code Syntax Highlighting - for more readable excerpts of programming languages including PHP, HTML, CSS, and XML amongst many others

Documentation