FOSCommentBundle recently added functionality that allows you to use some kind of markup parser to let your users post more than just plain text comments. The way it is implemented allows the developer to choose which parser for whatever language they desire.

In this article, we assume you are using Symfony2.0 with the deps file and bin/vendor management. For Symfony2.1 users, you are able to replace the parts of the instructions with composer, which is beyond the scope of this article.

To be able to use a markup parser, you must be using a commit of 0fb403c6f1 or newer, or the upcoming 1.1.0 version.

Dependencies

Because of the way that the BBCode parser we’re going to use works, we will need to additionally implement a HtmlPurifier to make sure that the HTML is safe for displaying. For this, we’ll be using ExerciseHtmlPurifierBundle. Follow the installation instructions provided by this bundle.

Done that?

Next we need to install the BBCode parser, add the following to your deps file and autoload.php:

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[StringParser_BBCode]
    git=http://github.com/merk/StringParser_BBCode.git
    target=stringparser-bbcode

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<?php
// ...
$loader->registerPrefixes(array(
    // ...
    'StringParser' => __DIR__.'/../vendor/stringparser-bbcode/src',
    // ...
));

And run bin/vendor install to install the parser.

Configuration

StringParser_BBCode comes with many different options about how to configure it, letting you specify which BBCode tags should be allowed and what they will be transformed into.

We will need to set up a service called BBCodeParser that implements ParserInterface from FOSCommentBundle, which has a single method, parse. We will use the service we implement to configure our StringParser_BBCode class, but you can use whatever method you’d like to get an instance of StringParser_BBCode into our new BBCodeParser.

Our example set up will enable [B] and [I] BBCodes, if you need more take a look at the documentation provided by StringParser_BBCode, there are more examples provided there.

Below is an example implementation of BBCodeParser, a class that will need to be placed inside a bundle in your application. Generally, an application will need to have an AppBundle to implement bits and pieces required for other bundles.

Once you’ve got your BBCoderParser set up the way you want it, you need to configure the Symfony2 container to tell it about the parser, and let FOSCommentBundle know about it.

The configuration example below sets up the ExerciseHTMLPurifier to disallow all HTML, combined with the Parser above, will remove all HTML and then convert the BBCode to HTML.

Security Risk

You must be careful with the HTMLPurifier configuration so that no unexpected HTML gets through the parser. You may expose your website to XSS attacks if not properly configured.

And you’re done. Any comments created from this point onwards will be parsed for BBCode and that will be converted to the HTML you’ve specified.