Adds possibility to configure Purifier-Filter dynamically

[fg-ok]

This change adds the ability to set a main configuration for Purifier as well as using the Filter with dynamically set configuration options.

[juriansluiman]

@fg-ok thanks for the contribution! I never seen the purify($html, $config = null); but it seems a very nice addition.

The only thing I wory about your implementation is the state you now hold for the config. Say you turn your examples around:

//Set config dynamically
$filter->setConfig(array('HTML.Allowed' => 'em'));
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //Outputs  <em>Hello World!</em>

// Some time later...
$filter = $this->getServiceLocator()->get('FilterManager')->get('htmlpurifier');
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //Outputs  <em>Hello World!</em>

As you notice, in the second example you would expect the <h1> come through, but it doesn't since you have set the config earlier. With the modular architecture of ZF2, there might be some module early on setting the config and this results in unexpected outcomes.

My suggestion is to keep it just very simple:

public function filter($value, $config = null)
{
    return $this->getPurifier()->purify($value, $config);
}

Thoughts @fg-ok ?

[juriansluiman]

Oops, it wasn't meant to close this PR :)

[fg-ok]

Yes, I am aware of the problem that config once set is still valid for the next call.
My pull-request was just a hasty and easy change, that will things make lightly better/more dynamic.

I got an idea how this change could be configurable consistent or not. Will add this ASAP.
Thanks for the input! :)

[fg-ok]

Added a second parameter to setConfig() and a method getConfig() as well.

Now the call could look like:

$filter = $this->getServiceLocator()->get('FilterManager')->get('htmlpurifier');

//Set config dynamically and temporarily 
$filter->setConfig(array('HTML.Allowed' => 'em'));
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //Outputs  <em>Hello World!</em>
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //2nd call, outputs  <h1><em>Hello World!</em></h1>

or...

$filter = $this->getServiceLocator()->get('FilterManager')->get('htmlpurifier');

//Set config dynamically and persistent 
$filter->setConfig(array('HTML.Allowed' => 'em'), true);
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //Outputs  <em>Hello World!</em>
echo $filter->filter('<h1 onclick="doSomeEvilStuff();"><em>Hello World!</em></h1>'); //2nd call, still outputs  <em>Hello World!</em>