timkelty / craft-asset-rev

CraftCMS plugin to aid cache-busting

CraftCMS Asset Rev (Cache Busting)

A Twig extension for CraftCMS that allows you to swap out asset file names with their revved version, as defined in a JSON manifest file.

Manifest files would most likely be generated by Grunt/Gulp modules, such as grunt-filerev-assets or gulp-rev.

Why?

In order to speed up the load time of your pages, you can set a far-future expires header on your images, stylesheets and javascript. However, when you update those assets you'll need to update their file names to force the browser to download the updated version.

You could append a query string to the asset url (e.g. css/main.css?v=24), but you should read here to find out why that's not an ideal solution.

Installation

Copy the assetrev folder to your craft/plugins directory and activate it from the Craft plugin settings page. Once activated, you may want to specify a custom path to your asset manifest file within the plugin configuration.

##Configuration The plugin comes with a config.php file that defines some sensible defaults.

If you want to set your own values you should create a assetrev.php file in your Craft config directory. The contents of this file will get merged with the plugin defaults, so you only need to specify values for the settings you want to override.

###Manifest Path manifestPath is relative to the base path of your Craft installation (whatever CRAFT_BASE_PATH is set to).

###Assets Base Path assetsBasePath will be prepended to the output of rev(). You can use any environment variables that you may have set in your general.php config file here.

###Example assetrev.php Config File

<?php
return array(
	'*' => array(
		'manifestPath' => 'resources/assets/assets.json',
		'assetsBasePath' => '{baseUrl}',
	),
);

Usage

Once activated and configured you can use the rev() function in your templates.

<link rel="stylesheet" href="{{ rev('css/main.css') }}">

css/main.css will be replaced with the corresponding hashed filename as defined within your assets manifest .json file.

If the contents of your manifest file are...

{
    "css/main.css": "css/main.a9961d38.css",
    "js/main.js": "js/main.786087f7.js"
}

then rev('css/main.css') will expand to css/main.a9961d38.css.

Note: If the plugin can't find your manifest file, it will just return the filename passed into rev(). This is helpful during development as you aren't required to keep rebuilding the manifest file each time you update an asset.