Assets Bundle

The Becklyn Assets Bundle is a high performance asset handler for symfony projects.

This bundle is a simplified and specialized replacement for symfony/asset.


composer require "becklyn/assets-bundle"

and then add the bundle in your bundles.php / AppKernel.

Load the routes (preferably only in dev):

    resource: "@BecklynAssetsBundle/Resources/config/routes.yaml"

Info / Purpose

This bundle aims to provide a way to transparently handle long-term caching of assets.

All assets in your entry points are copied (and possibly transformed) to public/assets/ and the file names modified, so that they contain the content hash of the given file. It also provides Twig functions to use these translated paths transparently in a symfony application.

In Twig the original filename is given to the asset* function and it automatically generates the HTML reference for the hashed file name.

The directory public/assets/ is completely cleared on cache clear, so it should exclusively be managed by this bundle.

All requests to the assets/ directory can be cached for a long time, like with a expiry date in the far future or even immutable headers.


The asset generation and preparation is done automatically. The assets are pregenerated on cache clear + warmup or on-the-fly generated if encountered with an empty cache.

In the configuration a mapping of namespaces to directories is defined. These namespaces are then used to retrieve paths to these files by using the @{namespace}/{path} syntax:

        build: build

In Twig, the following functions can be used:

{# automatically generates the <script></script> tags #}
{{ assets_js([
]) }}

{# automatically generates the <link> tags #}
{{ assets_js([
]) }}

{# just returns the URL #}
<img src="{{ asset("@build/img/logo.svg") }}" alt="Company Logo">

Asset Processing

Currently only one asset processor is included in the bundle. Asset processors are chosen by file extension and are supposed to transform the given file content. They are not supposed to alter the file in terms of minification, but to adjust import paths (like url(...) in CSS) to the new paths.

Currently registered processors:


File Extensions




Rewrite url(...) paths.

The asset processors are using the paths from the AssetCache. This implies a race condition, as the processor can only rewrite paths of files that were already added to the cache. So files with a processor are deferred and only processed after all other files are finished (at least if the command / cache warmer is used). There still can be race conditions, if files with processors depend on each other.


All configuration values with their description and defaults:

    # the entry points. Maps the namespace to the directory (relative to `%kernel.project_dir%`)
    # -> is required
        build: build
        bundles: public/bundles

    # the absolute path to the `public/` (or `web/`) directory
    public_path: '%kernel.project_dir%/public'
    # relative path to the directory, where the assets are copied to (relative to `public_path`)
    output_dir: 'assets'



The bundle provides a command to clear and warmup the cache:

# clear + warmup
php bin/console becklyn:assets:reset

# only clear
php bin/console becklyn:assets:reset --no-warmup

Normally these commands are not required, as the bundle automatically registers as cache clearer and cache warmer.


This command prints an overview over all registered namespaces. This is especially useful if you register paths programmatically outside of your configuration.