Which component's controller handle the form r

Question

After checking this post, I know that Joomla use task=X.Y to call the controller to handle the request.

But if I click NEW button on com_categories component, it will access the URL of /administrator/index.php?option=com_categories&view=items and containing the POST data as below:

Then the URL get redirected to /administrator/index.php?option=com_categories&view=item&layout=edit.

My question is why the URL /administrator/index.php?option=com_categories&view=items don't have the task=X.Y and it can redirect to /administrator/index.php?option=com_categories&view=item&layout=edit?

I know that it contains the POST data with task=item.add, but which controller convert this POST data to the destination URL and get redirected to that?

Thanks.

Answer 1

Actually (on 2.5.14), when you click on the "New" button in the Category Manger view, the first request generates a POST:

POST /administrator/index.php?option=com_categories&view=categories HTTP/1.1

POST requests usually send query strings in the HTTP message body not just in the URL, in this case the POST request has the following form data in the body:

filter_search   
filter_level    
filter_published    
filter_access   
filter_language 
limit   5
limitstart  0
order[] 1
order[] 1
order[] 1
order[] 1
order[] 2
batch[assetgroup_id]    
batch[language_id]  
batch[category_id]  
batch[move_copy]    m
extension   com_content
task    category.add
boxchecked  0
filter_order    a.lft
filter_order_Dir    asc
original_order_values   1,1,1,1,2
796194955f38a0d8db484c92d92ca5ce    1

You will notice this has a task parameter that has the value category.add (not item.add), this is taken into account by the JController class when getInstance($prefix, $config) is called in the com_categories entry point file:

$controller = JControllerLegacy::getInstance('Categories');

The JController class converts category.add into a $type of category and a $task of add. The $type value is used to assemble the path to the controller in conjunction with the components base path ( in this case /pathto/site/administrator/components/com_categories ).

So, when the instantiated JController class receives the ->execute($task) message in com_categories/categories.php entry point file:

$controller->execute(JRequest::getVar('task'));

it's actually already a controller of type CategoriesControllerCategory which is the what you would expect to handle the New button request.