Moodle Filters are little functionalities that keep an eye on Moodle content, looking for specific words or symbols. When they find what they are looking for, they ‘filter’ the content and transform it. Thus, a Moodle Filter has two parts: the ‘string’ (words of symbols it looks for) and the transformation.
Moodle includes a set of standard filters out-of-the-box, with additional filter functionality available through plugins. By adding multimedia, smart recognition and interaction sandboxes, they can greatly enhance the learner experience.
A particularly vibrant niche of contributed filters involve mathematical notation, with several filters for mathematical equations, graphs and even calculators available for Moodle.
Moodlers who are developers looking to increase ongoing use of their contributed plugins, should consider developing as Filter type to promote quick, practical use of their functionality.
Activating Moodle Filters
Moodle Filters can be activated for a whole site, a course, or even specific sections. On the respective management page, Moodle Filters can be set “Off”, “On” or “Off but available”. This last option lets you apply Moodle Filters to your own content.
The management pages will show a list of all the standard filters, and those added through plugins. (See ‘Installing Filter Plugins’ Below.)
The list of Moodle Filters can be arranged right from the management page. This is important because sometimes two or more filters will try to transform the same string. Moodle applies the Filter in the arranged order. So make sure you do not have redundant filters or that a filter on top is not interfering with another below.
Let’s see how to access each of the management pages by level:
On a Moodle site level, navigate to
Administration > Site administration > Plugins > Filters > Manage filters. It requires sitewide administrative permissions, which means you probably have to talk to your site’s IT guy.
On a Moodle course level, head to
Administration > Course administration > Filters. Teachers usually have permissions at this level, and they override the Moodle site’s. A teacher could disable for their course a filter that is “On” sitewide.
On a Moodle Activity, visit
Administration > Activity administration > Filters. If a Moodle Filter is “Off but available”, the filter usually comes as a button on the text editor for the content creator to apply it. If a student is posting on the Moodle Forum or an entry on the Moodle Wiki or the Moodle Glossary, they can use Moodle Filters at will.
Remember to ‘Save changes’ after you are done on the management page.
The Standard Moodle Filters suite
The Moodle Documentation lists 13 standard filters:
- Multimedia plugins takes HTML links that point to audio or video sources and replaces them with a fully-fledgeg media player.
- Activity names auto-linking looks for exact names of a Moodle Activity in a course and adds a hyperlink to that Activity. Database auto-linking and Glossary auto-linking dos the same but for entries on a Moodle Database or a Moodle Glossary available for the course, respectively.
- Algebra notation, MathJax and TeX convert mathematical expressions written in code or through an equation editor.
- Converts URLs into links and images, pretty self explanatory, saves the time of downloading, submitting and uploading images.
- Display emoticons as images displays emoticons as images.
- Email protection. Obfuscates email addresses to prevent spam.
- HTML tidy recognizes and renders HTML code.
- Multi-Language content provides space to add a same piece on content on many languages, and displays the version according to a user’s language settings.
- Word censorship adds a black fringe on a word if it is on a “bad words” lists you can edit.
Contributed Filter Plugins
At the date of writing, there were 62 Filter Plugins at the Moodle Plugin Directory.
Here are just some of the most popular Moodle Filters:
- Generico is a flexible text-adding utility. We covered how it was used to speed-up Moodle deployment at Endeavour College of Natural Health, Brisbane.
- PoodLL enables audio and video recording within Moodle.
See our coverage of #PoodLL.
- WIRIS Math & Science is a next-gen mathematics editor, supporting handwriting recognition, chemistry expressions and a calculator.
See our coverage of WIRIS.
See some standard and contributed filters in action at the moodle.org forums.