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File Versioner

Automatically generate unique hashed versions of static files and asset files for efficient and reliable browser caching.

Overview

This plugin automatically generates cache-busting hashed versions for both the static files within your webroot (JS, CSS, fonts etc.) as well as volume assets uploaded by users.

For static files, it does this by creating a scan command that you can run on every deployment:

Which can be accessed in your template via a v template filter:

For asset files, the versioning happens automatically when a new file is uploaded.

Background

When serving files in production it's common to configure your web server to avail of browser-caching by using the Cache-Control header. This instructs the user's browser to keep a local version of a particular file rather than contacting the server. This saves network requests and improves performance.

A common problem with browser-caching arises when a file's content changes. How does the browser know it's changed? If you told the browser to keep that file for 2 week it won't ask for that file again until then, meaning it will continue to have the old stale version.

File versioning is a solution to this. The idea is that you append a hash to the end of the file:

This means that when the content of the file changes, the hash also changed. When the hash changes, the URL changes. This means the user's browser will now always get the latest file, but will still avail of caching when that file remains unchanged.

Versioning Challenges

Actually implementing file versioning can be difficult. A website usually has two families of files:

• Static files: these are the files used during development. Think of them as your 'build-time' files
• Asset files these are the files uploaded during regular usage by the end-user. Think of them as your 'run-time' files

For static files you could manually version them by using a system like styles.v1.css styles.v2.css etc. but this is tedious and error prone. You could alternatively use your frontend task runner like gulp to do it for you, but this also requires manual intervention.

For asset files there are even less options. You could ask clients to manually version files before uploading them but this is unlikely to be adhered to.

Solution

The solution is to automatically version both static files and asset files. This plugin handles this by offering 'build-time' CLI commands that automatically version static files during deployment as well as transparent 'run-time' processing the automatically versions all user-uploaded assets.

Read more in our blog post about file versioning

Requirements

This plugin requires Craft CMS 3.0.0 or later.

Installation

To install the plugin:

1. Open your terminal and go to your Craft project:

2. Then tell Composer to load the plugin:

3. In the Control Panel, go to Settings → Plugins and click the Install button for File Versioner.

Configuration

Copy the example configuration file from the repo config/file-versioner.example.php to config/file-versioner.php in your project:

This configuration file allows you to control you versioning on a per-environment basis.

You should also add the @webroot/versions folder to your .gitignore for example:

Usage

Static Files

To generate versioned static files, run the following command as part of your deployment:

Template Filter

To reference your static files from your template, use the v Twig filter:

This will render your versioned file transparently:

Asset Files

For new files that are uploaded via the Control Panel, you don't have to do anything - they will be automatically versioned.

Behind the Scenes

Being the scenes the plugin keeps all versioned files in a separate @webroot/versions folder. This means your original files are never changed.

Static Files

For static files, the scan command will automatically search for all files in your @webroot folder that match the extensions you enabled via staticVersioningExtensions.

It will automatically exclude the cpresources folder plus any volumes in your webroot so as not to duplicate versioned files or rename anything else unessessarily.

The files that it finds will be md5 hashed and that hash value will be appended to their filename, before the extension.

A mapping of un-versioned files to versioned files is kept in the Craft cache. When you use the v template filter, the plugin simply looks up the original file path in your cache.

Caveats

There are a few caveats you should be aware of when developing with this plugin.

Using versions in CSS or JS

You cannot access versioned files outside of your .twig files. For example, you might have a background image within your CSS file:

The v template filter is not available in your CSS files so you cannot access the versioned file. A workaround is to use inline styles, for example:

Relative paths

Be careful using relative paths for static files within your versioned CSS or JS, they may cause 404s. For example:

As the above caveat mentioned, you can't version this font file. But because this uses a relative path, it will actually 404.

This is because all versioned assets are stored in a versions folder within you webroot. But this font file versioned at all, so doesn't exist in the versions folder.

Use absolute paths instead (to the non-versioned folder):

Local volume files

Currently, this plugin only works with local files in you filesystem's webroot.

Sourcemaps

Currently these won't work with versioning enabled. See for more:

https://github.com/weareferal/craft-file-versioner/issues/3

Support

Brought to you by Feral. Any problems email [email protected] or leave an issue on Github.