Bust static assets from the cache using content hashing
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-devUse the cacheBust task for cache busting static files in your application. This allows the assets to have a large expiry time in the browsers cache and will only be forced to use an updated file when the contents of it changes. This is a good practice.
Give the cacheBust a list of files that contain your resources and let it work it's magic.
_By default, it will bust the following file type: CSS, JavaScript, images and favicons You can manually add more if needed
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,
deleteOriginals: true
},
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>// Here is a short summary of the options and some of their
defaults. Extra details are below.
{
algorithm: 'md5', // Algoirthm used for hashing files
baseDir: './', // The base directory for all assets
cdnPath: false, // You're own CDN path
deleteOriginals: false, // Delete the original file after hashing
enableUrlFragmentHint: false, // Look for the URL fragment in URLs
encoding: 'utf8', // The encoding used when reading/writing files
filters: {}, // Filters used when searching the DOM for assets
ignorePatterns: [], // Ignore files that match given patterns
jsonOutput: false, // Output the original => new URLs to a JSON file
length: 16, // The length of the hash from a file
replaceTerms: [], // Replace terms in URLs
removeUrlFragmentHint: false, // Remove the URL fragment from URLs after hashing
rename: true, // Rename files instead of appending a query string
separator: '.' // The separator between the original file name and hash
}
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'
Type: String
Default value: false
When set, cachebust will try to find the asset files using the baseDir as base path.
You can override this at the file level, e.g:
assets: {
files: [
{
expand: true,
cwd: 'public/',
baseDir: 'public/',
src: ['modules/**/*.html']
},
{
baseDir: '/',
src: ['config/config.js']
}
]
} Type: String
Default value: false
When set, cachebust test paths against this string when attempting to determine a path to be remote or not. This allows all assets to be busted locally and than uploaded to your own CDN. This string will be ignored in paths during file-handling to find files in baseDir.
Type: Boolean
Default value: false
When set, cachebust will delete the original versions of the files that have been renamed. For example, style.css will be deleted after being copied to style.dcf1d324cb50a1f9.css.
Type: Boolean
Default value: false
When true, cachebust will search single and double-quoted strings in the given files for any resource ending in #grunt-cache-bust. See an example for more details.
Type: String
Default value: 'utf8'
The encoding of the file contents.
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.
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']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 grunt-cache-bust.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:
{
'/scripts/app.js' : '/scripts/app.23e6f7ac5623e96f.js',
'/scripts/vendor.js': '/scripts/vendor.h421fwaj124bfaf5.js'
}
Type: Number
Default value: 16
The number of characters of the file content hash to prefix the file name with.
Type: Array
Default value: []
Replace terms within URLs. See the replaceTerm folder in tests.
Type: Boolean
Default value: false
Removes the URL fragment after it's been processed.
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.
Type: String
Default value: .
The separator between the original file name and hash
grunt.initConfig({
cacheBust: {
assets: {
files: {
src: ['index.html', 'contact.html']
}
}
}
});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
]
}
},
assets: {
files: [{
expand: true,
cwd: 'src',
src: ['*.html'],
dest: 'dest/'
}]
}
}
});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 these 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" />v0.4.13 - 2015-02-27
- Fixes issue with deleting the original files when referenced in more than one source file.
- Fixed issue with hashe in the url of assets when referenced in CSS
v0.4.12 - 2015-02-26
- Fixed tests and implementation when deleting original files.
v0.4.12 - 2015-02-25
- Ignoring data-images when parsing CSS.
v0.4.12 - 2015-02-20
- Added support for Windows 8.1 and IE titles browser config file.
v0.4.2 - 2015-02-19
- Tidied up tests. Improved README readability.
v0.4.2 - 2015-02-18
- Improved detection of remote resources
v0.4.2 - 2015-02-18
- Fix for working with relative paths
v0.4.2 - 2015-02-15
- Added options to remove frag hints and use a local CDN. Busting multiple values in CSS files. Bust SVG xlink:href path. Override
baseDiron a per file basis.