Symfony2 cache warmer

Outdated article!

If it's a technical article, take care, maybe some informations are not exact anymore.
Otherwise, please keep in mind that this article was written quite a long time ago.

For this first post since 6 months, let me introduce to you the CacheWarmer class.

Cache warmer? What is this?

A cache warmer is just a class that writes in a file to store data. Really simple.

Look into you're app/cache directory. Here is an example of what you can find:

  • Global configuration
  • Translations
  • Assetic configuration
  • Doctrine proxies classes
  • Twig compiled templates
  • ...

Lot of things, created by cache warmers.

How to use cache warmer?

Juste create a file that extend the CacheWarmerInterface provided by the HttpKernel Component.


use Symfony\Component\HttpKernel\CacheWarmer\CacheWarmerInterface;

class MyCustomeCacheWarmer implements CacheWarmerInterface
    public function warmUp($cacheDir)
        // Create a file here
        // Write in it

    public function isOptional()
        // By default, all CacheWarmer are called by the `app/console cache:warmup` command.
        // But you can specify the `--no-optional-warmers` to skip non optional ones.
        return false;

For the implementation, you can take a look at the TemplatePathsCacheWarmer for example.

Of course, you have to declare your CacheWarmer as a service. Do not forget to tag it with kernel.cache_warmer:

<service id="my_custom.cache_warmer" class="path/to/MyCustomCacheWarmer">
    <tag name="kernel.cache_warmer" />

Now, if you run the command app/console cache:warmup (or app/console cache:clear without the --no-warmup option) your cache file should be created. (Search it in the app/cache/ folder).

To use your cached data, it's very simple. Look at TemplateLocator.

The TemplateLocator simply require the cached file and store the result into a var. To do the same thing, simply store a return statement in your file. For example, the app/cache/dev/templates.php file looks like this:

<?php return array (
    'template_name' => 'path/to/template',
    // ...

You're done. You can now use your custom CacheWarmer in your application. :)

Tags: symfony2, cache, file, cachewarmer