The Contao Managed Edition

Contao is available as a so-called Managed Edition. Compared to a regular Symfony application, a Managed Edition allows automatic configuration by third-party bundles. If you are familiar with Symfony Flex you might find some similarities but the Managed Edition was actually a thing before Symfony Flex even existed!

The Manager Plugin and the Manager Bundle

The heart of the Managed Edition consists of two main components:

The Manager Bundle contains the full application skeleton such as entry points, config files etc. thus giving us full control on how the application is built during an update. Hence, if you want to install e.g. Contao 4.7, you would require contao/manager-bundle in 4.7.*.

To start a new project, don’t just require the contao/manager-bundle because you’ll also need the post-install and post-update Composer scripts to be in place. Just run composer create-project contao/managed-edition [<directory>] [<version>] instead.

The core of the Manager Bundle is the special application kernel. Instead of loading e.g. bundles and routes from the app specific folders it asks all the installed Composer packages (or in other words, the other Contao bundles) for that information. It does so using the interfaces the Manager Plugin provides making your application fully autoconfigurable.

The Manager Plugin is a Composer plugin which hooks into Composer to automate tasks on every composer install or composer update (see how similar it works to Symfony Flex?). As mentioned in the section above, it also provides all the interfaces aka the API for other bundles to configure the Managed Edition.

Maybe an illustration helps you to understand how the pieces are put together:

graph LR; A[Managed Edition]-- requires -->B[contao/manager-bundle] A-- requires -->C[contao/news-bundle] A-- requires -->D[acme/another-bundle] B-- requires -->F("Everything needed to run a completely managed Contao.

contao/core-bundle
doctrine/dbal
symfony/framework-bundle
etc.") B-- requires -->E[contao/manager-plugin] C-- requires -->E D-- requires -->E E-- manages -->A style B fill:#fcc style E fill:#ffc

The key of a Managed Edition are the following lines in your composer.json which you’ll get automatically when you run composer create-project contao/managed-edition:

{
    "scripts": {
        "post-install-cmd": [
            "Contao\\ManagerBundle\\Composer\\ScriptHandler::initializeApplication"
        ],
        "post-update-cmd": [
            "Contao\\ManagerBundle\\Composer\\ScriptHandler::initializeApplication"
        ]
    }
}

So after every composer update or composer install, the ScriptHandler of the Managed Edition is called so it is able to initialize the application. Here are examples of what the ScriptHandler does to give you an idea about its responsibilities:

  • Creating the whole application structure. Folders such as the app and the web folders with the entry points.
  • It purges and rebuilds the cache
  • It creates symlinks

Do I need the Managed Edition?

It depends. If you have an existing Symfony full stack application and you want to install Contao to provide additional CMS functionality, probably not. You have full control about your application kernel and the configuration but it also means you have to adjust the settings for every Contao update (or any other Contao bundle update for that matter). If, however, you are planning to make Contao the most important part of your application (meaning most of what you are going to do is content management) you are likely better off using the Managed Edition. Updates are easier because your application auto-configures itself via the Manager Plugins of all the installed bundles. You can still control all of it through a global, application-wide Manager Plugin that is loaded at the very end but it maybe requires a bit more code.

To learn more about the Manager Plugin visit its dedicated article.

Application Structure Differences

Development of Contao 4 and its Contao Managed Edition was started before Symfony 4 was released. Since then the best practises and defaults of Symfony have changed slightly. If you are familiar with the default Symfony 4 application structure as used by the Symfony Skeleton for example, then it might help to know some of these differences.

  • Automatically loaded configuration files use the file extension .yml instead of .yaml.1
  • The automatically loaded file containing the routes definition is called routing.yml rather than routing.yaml.1
  • The public entry point is called web/ instead of public/.

1 See here for a list of configuration files, that are automatically loaded.