I want to display the username/last connection date/time and some other info on all of my Twig views (which all extend from a common Twig layout).
How can I achieve
The simplest solution is to embed controllers from your templates/layout. But beware that subrequests are costly and can affect performance significantly. If at some point you'll notice that the dev version of your app is slow as hell, then know that the reason is probably several subrequests on each request.
The next solution is Twig extensions. In most cases you'll want functions. You could call it like:
{{ user_info(user) }}
I started with embedding controllers first, but my dev version reached the point when most pages on my site were timing out in 30 seconds. I didn't know the reason first, but as soon as I found it out, I replaced all subrequsts with Twig extensions. Since then the performance is back to normal.
User is accessible as a predefined global variable, take a look at this, and if you want to reuse the same template fragment in all your templates take a look at the include tag.
I don't know if it was available when this question was posted in 2012, but I'd use Twig Globals.
From http://twig.sensiolabs.org/doc/advanced.html#globals :
Globals
A global variable is like any other template variable, except that it's available in all templates and macros:
$twig = new Twig_Environment($loader);
$twig->addGlobal('text', new Text());
You can then use the text variable anywhere in a template:
{{ text.lipsum(40) }}
I put the code in some place where it will get called each time, like the controller constructor or something like that.
Had this use-case just last month. Turned to render
command and it really worked great as called controller action does not have to have @Route
defined... not even a @Template
but that's up to you ;)