A modified Symfony2 .htaccess file that makes it possible to set the front controller from the Apache virtual host (kind of like Rails).

.htaccess

<IfModule mod_rewrite.c>
    RewriteEngine On

    ### Call the correct front controller. This is dependent on an environment variable being set
    ### in the virtual host configuration. SetEnv seems not to work, so here's an example with SetEnvIfNoCase:
    ###   <Directory /path/to/application/web>
    ###     SetEnvIfNoCase REQUEST_URI .* SYMFONY_ENV=dev
    ###   </Directory>
    ### This will force the following rules to call the dev front controller.

    # Make sure the prod front controller is called without a suffix.
    # (prod OR production) and file doesn't exist
    RewriteCond %{ENV:SYMFONY_ENV} prod [OR]
    RewriteCond %{ENV:SYMFONY_ENV} production
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.*)$ app.php [QSA,L]

    # dev
    RewriteCond %{ENV:SYMFONY_ENV} dev [OR]
    RewriteCond %{ENV:SYMFONY_ENV} development
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.*)$ app_dev.php [QSA,L]

    # any other front controller
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{ENV:SYMFONY_ENV} ^(.+)$
    RewriteRule ^(.*)$ app_%1.php [QSA,L]

    # Default to prod if there is no variable set (most secure)
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteRule ^(.*)$ app.php [QSA,L]
</IfModule>