grunt-cache-bust
Bust static assets from the cache using content hashing
Getting Started
If you haven't used grunt before, be sure to check out the Getting Started guide.
From the same directory as your project's Gruntfile and package.json, install this plugin with the following command:
npm install grunt-cache-bust --save-dev
Once that's done, add this line to your project's Gruntfile:
grunt.loadNpmTasks('grunt-cache-bust');
If the plugin has been installed correctly, running grunt --help
at the command line should list the newly-installed plugin's task or tasks. In addition, the plugin should be listed in package.json as a devDependency
, which ensures that it will be installed whenever the npm install
command is run.
The "cacheBust" task
Use the cacheBust task for cache busting static files in your application. This allows them to be cached forever by the browser, just point the task towards any file that contains references to static assets.
Currently supported static assets: CSS, JavaScript, images and favicons
Note: Remote URLs for CSS, JavaScript, and images are ignored by cacheBust. This assumes that remote URLs for these assets will be CDN hosted content, typically for well known libraries like jQuery or Bootstrap. For example, all of below URLs will be ignored:
<link href="//netdna.bootstrapcdn.com/twitter-bootstrap/2.3.2/css/bootstrap-combined.min.css" rel="stylesheet">
<link href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css" rel="stylesheet">
<script src="//ajax.googleapis.com/ajax/libs/angularjs/1.0.6/angular.min.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script type="text/javascript" src="http://code.jquery.com/qunit/qunit-1.12.0.js"></script>
<img src="https://secure.gravatar.com/avatar/d3b2094f1b3386e660bb737e797f5dcc?s=420" alt="test" />
Overview
In your project's Gruntfile, add a section named cacheBust
to the data object passed into grunt.initConfig()
.
grunt.initConfig({
cacheBust: {
options: {
encoding: 'utf8',
algorithm: 'md5',
length: 16
},
assets: {
files: [{
src: ['index.html']
}]
}
},
})
<!doctype html>
<html>
<head>
<title>This is a test page</title>
<link rel="stylesheet" href="assets/standard.css" />
</head>
<body>
<img src="assets/standard.jpg" alt="bird">
<script defer src="assets/standard.js" type="text/javascript"></script>
</body>
</html>
All single and double-quoted strings in the target files with "#grunt-cache-bust" appended to the URL will be cache busted.
Options
options.algorithm
Type: String
Default value: 'md5'
algorithm
is dependent on the available algorithms supported by the version of OpenSSL on the platform. Examples are 'sha1'
, 'md5'
, 'sha256'
, 'sha512'
options.baseDir
Type: String
Default value: false
When set, cachebust
will try to find the asset files using the baseDir as base path.
options.enableUrlFragmentHint
Type: Boolean
Default value: false
When true, cachebust will search single and double-quoted strings in scripting languages such as PHP for asset paths. Asset paths must have the #grunt-cache-bust
URL fragment appended. See an example for more details.
options.encoding
Type: String
Default value: 'utf8'
The encoding of the file contents.
options.filters
Type : Object
Default value:
{
'SELECTOR' : function() { return this.attribs['ATTR']; }
}
The key in the object is the selector
, and the value provided is the filter. Filters will be merged with the defaults above. See an example for more details.
options.ignorePatterns
Type: Array
Default value: []
This is a regex test against a file reference. If returned true for patterns in the array, then that file will be ignored.
ignorePatterns: ['test', 'requirejs']
options.jsonOutput
Type: Boolean|String
Default value: false
When set as true
, cachbust
will create a json file with an object inside that contains key value pairs of the original file name, and the renamed md5 hash name for each file.
The default output file will be named cachebuster.json
and is relative to the root of the project, or the baseDir
option if set.
Alternatively, you can set this option as a string i.e. example-file-name.json
, and this will be used.
Output format looks like this:
{
'app.js' : 'app_23E6F7AC5623E96F7AC56293E6F7AC56.js',
'vendor.js': 'vendor_KJJKNB1FHjh421fwaj124bfaf52jwWAA.js'
}
options.length
Type: Number
Default value: 16
The number of characters of the file content hash to prefix the file name with.
options.rename
Type: Boolean
Default value: true
When true, cachebust
will rename the reference to the file and the file itself with the generated hash. When set to false, then a query string parameter is added to the end of the file reference.
Usage Examples
Basic Asset Cache Busting
grunt.initConfig({
cacheBust: {
files: {
src: ['index.html', 'contact.html']
}
}
});
Custom Options
grunt.initConfig({
cacheBust: {
options: {
algorithm: 'sha1',
length: 32,
baseDir: '.tmp/public/',
filters: {
'script' : [
function() { return this.attribs['data-main']; }, // for requirejs mains.js
function() { return this.attribs['src']; } // keep default 'src' mapper
]
}
},
files: [{
expand: true,
cwd: 'src',
src: ['*.html'],
dest: 'dest/'
}]
}
});