Grunt Bustr

A static asset versioning plugin for gruntjs which can be used to bust browser cache on a per file basis.

Methodology

Lots of cache busting plugins append a MD5 or similar hash to the file name in order to get the user's browser to request the new file. A hash proves uniqueness but is not meaningful to humans, a number that is simply incremented gives uniqueness and shows direction. When something is broken in production and you need to know is the browsers is processing an old version of your js or css a simple number can help. Timestamps are even better, they add a third dimension to this by telling you exactly when the file was built while providing uniqueness and direction.

This plugin uses the mtime of the files it finds in the directories you provide and writes those values along with the file name to a version file which your server code would use when including these assets in you html files/templates. The date format that is written in ascending resolution: YYYYMMDDHHMMSS. The reason this version file is needed because each file gets its own version number which means if you only change one file, only that file has its cache busted.

Getting started

Requirements

• Grunt >= 0.4
• An empty json file to store the values

Installing

Install to your project by either adding grunt-bustr to you package.json as a dependency or simple run npm install grunt-bustr. Create an empty file to store the values by running touch version.json, then specify that file in the config (example below).

Sample config

module.exports = function(grunt) {
  grunt.initConfig({
		bustr: {
			css: {
				src: 'src/css/', // top level directory to look for files
					options: {
						version: 'version.json' // file that the build values will be written to
					}
			},
			js: {
				src: 'src/js/',
				options: {
					version: 'version.json'
				}
			}
		}
	});
  grunt.loadNpmTasks('grunt-bustr');
};

Contributing

Patches and/or ideas for improvement are welcome.

License

Copyright (c) 2014 Kevin Mulvey, Shutterstock Inc.
Licensed under the Apache v2 license.