Silex slugs cause 404 page not found - php

Question

Following the documentation, Silex allows "slugs" to be passed in via the URL for use within your code.
The following example works:
$app = new Silex\Application();
$app->get('/', function () {
return 'HAI';
});
However, the following gives a 404 Not Found:
$app = new Silex\Application();
$app->get('/{slug}', function ($slug) {
return 'HAI' . $slug;
});
How can I fix this 404?
In case it's of any relevance, here's my Apache Vhost:
<VirtualHost 127.0.0.1:80>
DocumentRoot "/var/www/Silex/web"
DirectoryIndex index.php
<Directory "/var/www/Silex/web">
AllowOverride All
Allow from All
</Directory>
</VirtualHost>
...and my directory structure:
/src
|-- bootstrap.php
/tests
/vendor
/web
|-- index.php

Answer 1

It turns out that this was an Apache issue. It was assumed that you could either use a .htaccess file, or a vhost. You actually need to use both.
.htaccess:
FallbackResource /index.php
Note: You can only use FallbackResource if using Apache 2.2.16 or higher.
vhost
<VirtualHost 127.0.0.1:80>
DocumentRoot "/var/www/Silex/web"
DirectoryIndex index.php
<Directory "/var/www/Silex/web">
AllowOverride All
Allow from All
</Directory>
</VirtualHost>
An alternative is to place the contents of the .htaccess file (the FallbackResource directive) within the vhost itself, and get rid of the htaccess.
As soon as I added the .htaccess, the slug in my second example worked.