Calling the extension

When a user opens the web page containing our blog in their browser, this request (Request) will be forwarded to the remote TYPO3 Server. Then TYPO3 starts the processing of this request straight away.

A request generally contains the identifier of the page (the so called page slug) that should be generated (e. g. /blog). Using this page identifier, TYPO3 searches all relevant content elements on the specific page and converts these to HTML code one after another. While processing this page request, TYPO3 discovers the content element for our example extension, the so called plugin. This plugin should display a list of all blogs. Each with an individual title, a short description and the amount of all enclosed posts. In figure 3-4 you can see the output of the plugin in the frontend. This output is embedded within the greater overview of the page.

../_images/figure-3-4.png

Figure 3-4: Output of the plugin of our example extension

The process of eradication is first forwarded to the dispatcher of Extbase by TYPO3. Before the execution is handed to our own controller code, the dispatcher and the parent ActionController complete several preliminary tasks before they hand the further processing on to the according position within the code of our blog example:

  • It interprets the incoming request and bundles all relevant information into a Request object.
  • It prepares the Response object as a container for the result of the request.
  • It loads the configuration of our extension from the different sources and makes it available.
  • It determines whether or not the request was manipulated in an illegal manner and when this is the case deflects it (e.g. in of case maliciously added form input field).
  • It sets up the persistence layer which performs the persisting of new or changed objects.
  • It prepares the cache in which the content is stored for faster reuse.
  • It instantiates and configures the controller of our extension which controls further processing within the extension.

When these preparations are fulfilled, we are able to travel to the first stop of our destination: the controller. In our example all further processing is assigned to the BlogController. A reference to the request and the response is handed over.

The class BlogController can be found in the file EXT:blog_example/Classes/Controller/BlogController.php. The complete name of the controller is \MyVendor\BlogExample\Controller\BlogController. At first this might seem long-winded but the syntax follows a very strict convention.