====== Action Router ======

The [[xref>ActionRouter]] is the central part that decides what should happen on a request to a Dokuwiki instance based on the [[action mode]].

===== Action Routing =====

The ActionRouter uses the ''do'' parameter to determine which action to load. Each action has its own class in ''inc/Action'' inheriting from [[xref>AbstractAction]] or one of it's descendants.

When the router considers running an action, there are several steps (methods) that are called on the Action class. All steps can still abort the action, either because some requirements aren't met or because no further processing is needed within the action. When ever an abortion happens, a different action (usually ''show'', ''redirect'' or ''denied'') will be loaded and processing starts again.

  - check if the action is disabled through [[config:disableactions]] or by the auth backend
    * if yes, shows a message and switches to ''show'' or ''redirect'' actions for GET and POST request respectively
  - ''Action::checkPreconditions''
    * The action itself can do custom checks that are required to use this action. An [[xref>ActionException]] is to be thrown if permissions aren't met
  - ''Action::minimumPermission''
    * The action returns the minimum [[:ACL]] permission needed to execute the action with the current page context. If that minimum is not met, the ''denied'' action is loaded
  - ''Action::preProcess''
    * Any code that should be executed by the action before output is sent to the browser happens here. Processing can still be aborted by throwing an ''ActionExeption''

Once all these steps have been processed, the final action is known and set within the ActionRouter instance.

===== Output =====

Once the action has been decided, DokuWiki continues the flow, loads the template and will finally reach a call to [[xref>tpl_content()]] which gets the current action from the router and calls ''Action::tplContent()'' on it which returns the actual HTML to output.

Note, that not all actions may have a ''tplContent'' method, because they either abort to a different action earlier or because they abort the whole further flow and output their own content (think ''export_html'').

===== Action Plugins =====

Action Plugin authors do not need to think much about the action router, previous events still work as before.

The [[devel:event:ACTION_ACT_PREPROCESS]] event basically wraps around all the steps under [[#Action Routing]]. Plugins that prevent the default action in this event's BEFORE phase will then later be handled in the new ''Plugin'' action which has a ''tplContent'' method that triggers [[devel:event:TPL_ACT_UNKNOWN]].


==== Change action within a POST request ====
If you use the [[devel:event:ACTION_ACT_PREPROCESS]] event, and you have to redirect to the 'show' action, you have to use the 'redirect' action actually. This will reset the parameters as well.