Joomla Extensions Development

Dispatching the component
Prev	The lifetime of a component	Next

Dispatching the component

The dispatcher object has a dispatch() method. This method looks in the request data to figure out which controller it needs to instantiate and which task it should execute on it. The controller object is instantiated through your component's MVCFactory service and its execute and redirect methods are called on it. So, yes, this is basically what your old Joomla 3 MVC controller.php file was doing.

Tip

	Tip
Having a custom dispatcher means that you can manipulate the controller and task based on other request variables. This is very important when your component is accessed outside of a Joomla menu item (no Itemid in the request variables). In this case Joomla always uses the default (Home) menu item for the current language. This means that you may be getting a `controller`, `view` or `task` request variable — as well as other variables which might mess with your component, like `id` — from the Home menu item. Your Dispatcher is responsible for figuring out if this is the case and fix the input variables to prevent weird bugs / showing the wrong page of your component when it's accessed without a menu item id, e.g. a URL like `/component/example?view=foobar`. This is something which has happened a lot when I converted my own extensions to Joomla 4, including LoginGuard (the extension contributed as Joomla's Multi-factor Authentication feature in Joomla 4.2).

Having a custom dispatcher means that you can manipulate the controller and task based on other request variables.

This is very important when your component is accessed outside of a Joomla menu item (no Itemid in the request variables). In this case Joomla always uses the default (Home) menu item for the current language. This means that you may be getting a controller, view or task request variable — as well as other variables which might mess with your component, like id — from the Home menu item.

Your Dispatcher is responsible for figuring out if this is the case and fix the input variables to prevent weird bugs / showing the wrong page of your component when it's accessed without a menu item id, e.g. a URL like /component/example?view=foobar. This is something which has happened a lot when I converted my own extensions to Joomla 4, including LoginGuard (the extension contributed as Joomla's Multi-factor Authentication feature in Joomla 4.2).

Prev	Up	Next
Getting the Dispatcher	Home	Directory structure

Work In Progress

Dispatching the component

Login

Tags