Copyright (c) 2007 Morgan Bertin, Tristan Rivoallan, Brice Tilmont
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
sfPayloadFilterChainPlugin plugin
The sfPayloadFilterChainPlugin is an implementation of the Intercepting Filter design pattern.
It provides means to apply filtering to a custom "payload".
Features
- Support for multiple chain "profiles"
- Built on symfony classes
Installation
symfony plugin-install http://plugins.symfony-project.com/sfPayloadFilterChainPlugin
Usage
Preambule
This plugin does not provide any concrete filter nor payload implementations. The application developer is responsible for providing these.
The following examples describe a possible implementation of the filtering of a blog post comment.
Defining a filtering profile
This means that any post comment payload passed through the filter chain will be filtered sequentially using the defined filters.
Executing the filter chain on a comment text will :
- replace forbidden words in it with "CENSORED"
- replace plain text urls with their HTML (
<a href=...) equivalent
- replace smileys with appropriate
<img />
Specifying filters
Filters specification is done in your application's config/pfc/filters.yml file.
Let's specify the filters we mentioned in the profiles.yml file :
censor_bad_words:
enabled: on
class: myCensorshipFilter
params:
bad_words: [poil, couille, nichon](bite,)
replacement_word: *CENSORED*
urls_to_html:
enabled: on
class: myUrlsToHtmlFilter
params:
enable_nofollow: on
expand_smileys:
enabled: on
class: mySmileyExpansionFilter
params:
base_url: images/smileys
Implementing filters
Some notes :
* filters must extend the sfFilter class
* params defined in filters.yml are available through filter's getParameter('name', 'default_value') method
Here's a sample implementation of the myCensorshipFilter filter :
<?php
# lib/filter/myCensorshipFilter.class.php
class myCensorshipFilter extends sfFilter
{
/**
* Replace some words in text by a configurable replacement word.
*
* @param string $text
* @return string
*/
public function execute($chain, $payload)
{
// Get forbidden words from filter specification
$forbidden_words = $this->getParameter('bad_words', array());
// Retrieve text from payload
$text = $payload->getText();
// Replace words in text. Only full words occurences are replaced
foreach($forbidden_words as $word)
{
$pattern = sprintf('/\b%s\b/i', $word);
$text = preg_replace($pattern, $this->getParameter('replacement'), $text);
}
// Replace payload text
$payload->setText($text);
// Execute next filter in chain
$chain->execute($payload);
}
}
Implementing payload
The developer must provide a payload object that can be used by the filter chain. Our example deals only with text transformation, so let's implement an appropriate payload :
<?php
# lib/payload/myTextPayload.class.php
class myTextPayload
{
public function getText()
{
return $this->text;
}
public function setText($text)
{
$this->text = $text;
}
}
Executing filter chain on a payload
Manually, in an action
<?php
# apps/blog/modules/comment/actions.class.php#executeAddComment
// Create payload
$payload = new myTextPayload();
$payload->setText($this->getRequestParameter('comment_text'));
// Filter payload
$chain = new pfcPayloadFilterChain();
$chain->loadProfile('post_comment');
$chain->setPayload($payload);
$chain->execute();
// Save comment
$comment = new PostComment();
$comment->setText($payload->getText());
$comment->save();
Automatically, in model
<?php
# lib/model/PostComment.php
public function save()
{
// Create payload
$payload = new myTextPayload();
$payload->setText($this->getText());
// Filter payload
$chain = new pfcPayloadFilterChain();
$chain->loadProfile('post_comment');
$chain->setPayload($payload);
$chain->execute();
// Save comment
$this->setText($payload->getText());
parent::save();
}
Changelog
2007-03-14 | 0.1.0 beta
Initial public release.
Tristan Rivoallan 
