[TYPO3-mvc] Displaying and modifying session data on same page

[Jan Kornblum]

Hi Bernd,

> you need to change the handling of action.
> modifying session-data can not be done by a special plugin, which might be 
> executed very late, but on any plugin of yours, or an 'invisible' plugin on 
> every page.
> that is just for actions to modify session data.
>
> e.g. the TYPO3 (FE-)login/logout is handled before any rendering takes place. 
> independent of any positioning of a login-plugin, so you can login to any 
> page with just the right parameter in the page call. content in the page can 
> be shown according the login state.
>
> you might use a hook or include an invisible plugin in every page by 
> typoscript or a real plugin without output in the page header-area.
>
> be careful if you handle session-modifying action in every plugin: only the 
> first plugin needs to handle the action and unset the request or set a flag 
> for following plugins, so the action is not processed twice or more.

thanks for your explanations. Although my solution seems to be o.k. for 
this case, i'm interested in how to realize this using a hook. This 
seems more comfortable (e.g. extension distribution) than having to 
include any hidden plugins or similar.

As i've never used any hook, how does this work? Which hook should i 
used preferred and is it possible to call any controller action 
directly from this? How to get from a hook into the extbase context?

Regards, Jan