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WARNING: You are browsing the documentation for Symfony 4.0 which is not maintained anymore. Consider upgrading your projects to Symfony 5.0.

Asset Versioning

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3.3 4.1 4.2 4.3

Asset Versioning

Tired of deploying and having browser's cache the old version of your assets? By calling enableVersioning(), each filename will now include a hash that changes whenever the contents of that file change (e.g. app.123abc.js instead of app.js). This allows you to use aggressive caching strategies (e.g. a far future Expires) because, whenever a file change, its hash will change, ignoring any existing cache:

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// webpack.config.js
// ...

Encore
    .setOutputPath('public/build/')
    // ...
+     .enableVersioning()

To link to these assets, Encore creates a manifest.json file with a map to the new filenames.

Loading Assets from the manifest.json File

Whenever you run Encore, a manifest.json file is automatically created in your outputPath directory:

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{
    "build/app.js": "/build/app.123abc.js",
    "build/dashboard.css": "/build/dashboard.a4bf2d.css"
}

In your app, you need to read this file to dynamically render the correct paths in your script and link tags. If you're using Symfony, just activate the json_manifest_file versioning strategy:

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# config/packages/framework.yaml
framework:
    # ...
    assets:
        # feature is supported in Symfony 3.3 and higher
        json_manifest_path: '%kernel.project_dir%/public/build/manifest.json'

That's it! Just be sure to wrap each path in the Twig asset() function like normal:

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<script src="{{ asset('build/app.js') }}"></script>

<link href="{{ asset('build/dashboard.css') }}" rel="stylesheet" />

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.