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 