Title: Text Filter Suite
Author: Dougal Campbell
Published: <strong>December 10, 2004</strong>
Last modified: June 3, 2015

---

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This plugin **hasn’t been tested with the latest 3 major releases of WordPress**.
It may no longer be maintained or supported and may have compatibility issues when
used with more recent versions of WordPress.

![](https://s.w.org/plugins/geopattern-icon/text-filter-suite.svg)

# Text Filter Suite

 By [Dougal Campbell](https://profiles.wordpress.org/dougal/)

[Download](https://downloads.wordpress.org/plugin/text-filter-suite.1.4.zip)

 * [Details](https://wordpress.org/plugins/text-filter-suite/#description)
 * [Reviews](https://wordpress.org/plugins/text-filter-suite/#reviews)
 *  [Installation](https://wordpress.org/plugins/text-filter-suite/#installation)
 * [Development](https://wordpress.org/plugins/text-filter-suite/#developers)

 [Support](https://wordpress.org/support/plugin/text-filter-suite/)

## Description

The Text Filter Suite (“TFS”, hereafter) is a WordPress plugin which
 adds some 
new text filtering functions. In a sense, the core TFS functions could be considered
a “meta filter”, because they actually provide a framework that let you construct
new filters fairly easily. They also provide an easy way to apply filters to post
content and comments on a per-post basis.

#### Huh? Can you repeat that in English?

Okay, let’s try a real-world example. A common feature on many web
 sites is the
automatic handling of acronyms. You’ll often see an acronym such as “XHTML” displayed
in an alternate style, and when you hover your mouse pointer over it, you get a 
tool-tip which displays the definition (“eXtended HyperText Markup Language”, in
this case). You don’t want to have to type in the markup for this every time you
post something, and automation is what computers are for, right? So, there are several
plugins available to handle this sort of automated text subsitution.

TFS comes with the “TFS Acronymit” plugin to perform this function.
 It’s based 
on Matt Mullenweg’s original “Acronymit” function, but with a couple of improvements.
In Matt’s original function, you had to keep the acronym list sorted, longest-to-
shortest, and it could get confused by recursive acronyms like ‘PHP’ (“PHP Hyptertext
Processor”) or GNU (“GNU’s Not Unix”). TFS Acronymit does not have those restrictions.

For those who think that expansion of technical acronyms is “teh sux0r”
 (i.e. “
boring”), TFS comes with a variety of more entertaining filters. The current set
includes “chef”, “fudd”, “jive”, “kraut”, “pirate”, and of course, the aforementioned“
acronymit”. As a word of caution, the “jive” and “kraut” filters are not what you
would call “politically correct”. By default, if the “TFS Pirate” filter is active,
it will automatically apply itself to all content on Talk Like a Pirate Day (September
19). If you do not want this filter to automatically activate, set the value of 
the “$talk_like_a_pirate” variable at the top of the plugin source to “false”.

The “TFS Acronymit” filter is automatically applied to all posts
 whenever it is
active. You do not need to set special post custom fields in order to use it. Just
activate the plugin, and you’re ready. To modify which acronyms are defined, see
the list at the beginning of the plugin, and modify it as you like, following the
format you see there.

It is possible to use the TFS core without activating any additional
 plugins. You
can do this with any built-in PHP function accepts a single string as a parameter
and returns a string. For example, you could set a post custom “content_filter” 
with the value “strrev”, and the contents of the post would be displayed backwards,
or with a value of “strtoupper” to convert the content to all uppercase text.

You can only specify a single function in each post custom field.
 However, you 
can chain multiple functions together by using the key more than once. For instance,
if you wanted all comments for a post to display in uppercase Elmer Fudd text, you
would set two post custom fields:

comment_filter = strtoupper
 comment_filter = fudd

HOWEVER, note that using PHP built-in functions in this way will bypass
 the power
of the filter_cdata_content() function, which means that it can and will mangle 
your HTML tags, possibly rendering them useless. For example, applying the strrev
function to the string “

<

p>” will
 transform it into “>p<“, which will confuse your browser in new and wonderful
ways.

NOTE: These filters can be very CPU intensive. For one thing, they make
 extensive
use of regular expressions, which can be expensive on their own. And for another,
they break your content into many small chunks, in order to separate the filterable
text from the HTML code, and the filters run separately on each text chunk found.
This probably won’t be a problem in most cases. But if you have long posts being
filtered, and you get a lot of traffic, it could start to add up. A caching plugin(
e.g., WP Super Cache, or W3 Total Cache) would probably help in that case.

### The Future

I will one day release a version 2.0 of this plugin which will be completely
 refactored.
You can probably expect to see: * Consolidate the code so that it is not a collection
of separately-enabled mini-plugins. * PHP5 OOP architecture to encapsulate everything.*
An actual admin interface to select which filters are enabled, which bits of content
you will allow to be filtered (post titles, post content, comments, blog title, 
widget titles, etc), whether to auto-activate the Pirate filter on Talk Like a Pirate
Day, etc.

Eventually, there may also be a way to edit the string substitutions so that
 you
can tailor it to your tastes.

### Credits

I created TFS on my own, but I borrowed ideas from several sources. Here are
 some
links you might also want to check out:

    ```
    PhotoMatt's original Acronymit code:
      http://photomatt.net/scripts/acronymit

    Simon Willison and I traded some ideas when I started my original hack
    for Talk Like a Pirate Day, in 2003:
      http://simon.incutio.com/archive/2003/09/19/aaar

    I borrowed, modified, and mangled a ton of stuff from Adam Kalsey's
    "MovableJive" plugin for Movable Type. See tfs-jive, tfs-chef, tfs-fudd,
    and tfs-kraut.
      http://kalsey.com/2003/02/movablejive/

    If all you want to do is stuff like the acronym definitions (or similar
    "turn this shorthand into a tag" substitions), then Michel Valdrighi's
    "Tag, You're It" plugin is really a better solution:
      http://zengun.org/weblog/archives/2004/05/tag-you-re-it

    The original inspiration that led to TFS was my desire to apply a
    "pirate" filter on my blog for "Talk Like a Pirate Day", which is on
    September 19 of each year:
      http://talklikeapirate.com/
    ```

## Installation

Technically, all you need to do is copy the “text-filter-suite” folder
 into your“
wp-content/plugins” directory, then activate the “TFS Core” plugin from the WordPress
admin interface. But, more generally, you’ll probably want some of the other filter
files, as well. The easiest thing to do will be to just copy all of the “.php” files
to your plugins directory, and only activate the ones that interest you. But you
can omit any of the “tfs-whatever.php” files (other than tfs-core) that don’t interest
you.

#### Using the filters

Generally, you’ll probably want to activate a filter just for specific
 posts. You
do this by adding special “post custom fields” in the “Write Post” form.

Custom fields are composed of two parts: the “key” and the “value”. The
 two special
keys that activate TFS are “post_filter” and “comment_filter”. In either case, the
value should be the short name of the TFS filter you wish to apply, e.g. “pirate”
or “fudd” (without the quotation marks).

Setting the “post_filter” key will apply the filter to the main post
 text. Setting
the “comment_filter” key will apply the filter to the text of all comments on the
post.

#### Technical mumbo-jumbo

There are only two core TFS functions, plus two more to support the
 per-post content
and comment filtering based on post custom fields. The main entry point is the “
filter_cdata_content” function. A TFS filter will call filter_cdata_content, passing
the content and the name of a second function. The magic of filter_cdata_content()
is that it will only mangle regular text, leaving HTML tags alone. It will automatically
call out to the named function, passing it each chunk of non-HTML-tag text (AKA “
CDATA”, or “Character Data”, in XML parlance) in turn.

The other core function is “array_apply_regexp”. This support function
 isn’t required
for every filter, but it is at the core of the included TFS filters, such as the“
pirate” filter. It accepts an associative array of regular expressions and replacements,
and the content to be filtered. Examine the source of the “chef” and “fudd” filters
for some simple examples.

The per-post support functions are “tfs_content_filter” and
 “tfs_comment_filter”.
These functions are automatically applied to each post and its contents. They look
for the “content_filter” and “comment_filter” post custom fields, and apply the 
appropriate filter functions if they are found.

## Reviews

There are no reviews for this plugin.

## Contributors & Developers

“Text Filter Suite” is open source software. The following people have contributed
to this plugin.

Contributors

 *   [ Dougal Campbell ](https://profiles.wordpress.org/dougal/)

[Translate “Text Filter Suite” into your language.](https://translate.wordpress.org/projects/wp-plugins/text-filter-suite)

### Interested in development?

[Browse the code](https://plugins.trac.wordpress.org/browser/text-filter-suite/),
check out the [SVN repository](https://plugins.svn.wordpress.org/text-filter-suite/),
or subscribe to the [development log](https://plugins.trac.wordpress.org/log/text-filter-suite/)
by [RSS](https://plugins.trac.wordpress.org/log/text-filter-suite/?limit=100&mode=stop_on_copy&format=rss).

## Changelog

#### 1.4 – 2015-06-03

 * Added ‘?filter=foo’ URL option back in, with a whitelist of allowed
    functions.

#### 1.3 – 2012-09-18

 * Fixed PHP opening shorttag in tfs-acroymit.php
 * Eliminated PHP warnings in debug mode
 * Removed all closing ?> php tags per WP standards
 * Killed generic ‘filter’ $_REQUEST variable checking

#### 1.2 – 2010-12-10

 * Added this changelog to the readme
 * Moved the is_feed() handling into the init, to avoid breaking in
    WordPress 3.1.
 * Added notes about the filters being CPU intensive.

## Meta

 *  Version **1.4**
 *  Last updated **11 years ago**
 *  Active installations **Fewer than 10**
 *  WordPress version ** 1.5 or higher **
 *  Tested up to **4.3.34**
 * Tags
 * [comments](https://wordpress.org/plugins/tags/comments/)[content](https://wordpress.org/plugins/tags/content/)
   [filters](https://wordpress.org/plugins/tags/filters/)[fun](https://wordpress.org/plugins/tags/fun/)
   [funny](https://wordpress.org/plugins/tags/funny/)
 *  [Advanced View](https://wordpress.org/plugins/text-filter-suite/advanced/)

## Ratings

 4.5 out of 5 stars.

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## Contributors

 *   [ Dougal Campbell ](https://profiles.wordpress.org/dougal/)

## Support

Got something to say? Need help?

 [View support forum](https://wordpress.org/support/plugin/text-filter-suite/)

## Donate

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