Assetic not generating any files - twig

Question

I am using Assetic with Twig but not the symfony2 framework.
Here's how the project is set up
/site
/template
/css
/public_html
/css
The raw css is stored under /site/template/css and I want assetic to minify the css and output it to /public_html/css.
Here's how assetic is set up as a twig extension
$factory = new AssetFactory(//absolute path to `/site/template/`);
$factory->setDefaultOutput(//absolute path to `/public_html/`);
$factory->setDebug(false);
$twig->addExtension(new AsseticExtension($factory));
Then in my template:
{% stylesheets 'css/screen.css' output='css/*' %}
<link href="{{ asset_url }}" type="text/css" rel="stylesheet" />
{% endstylesheets %}
I can see that assetic has generated a unique url in the final output:
<link href="css/00da241.css" type="text/css" rel="stylesheet" />
However, if I look in /public_html/css, the files are never generated!
I am using a Windows 7 server with apache and PHP has no issues writing files anywhere.
What could be causing this?

Answer 1

What you've done here is asking assetic to generate URL's to assets (using twig).
But assets urls don't point to any file yet. You still have to generate them, using a dump script:
<?php
use Assetic\AssetWriter;
use Assetic\Extension\Twig\TwigFormulaLoader;
use Assetic\Extension\Twig\TwigResource;
use Assetic\Factory\LazyAssetManager;
$am = new LazyAssetManager($factory);
// enable loading assets from twig templates
$am->setLoader('twig', new TwigFormulaLoader($twig));
// loop through all your templates
foreach ($templates as $template) {
$resource = new TwigResource($twigLoader, $template);
$am->addResource($resource, 'twig');
}
$writer = new AssetWriter('/path/to/web');
$writer->writeManagerAssets($am);
This script uses twig templates to define which files to dump.
You will have to define the $templates variable and the $twig variables of course.