A Broccoli plugin for adding revision checksums to file names

A Broccoli plugin that adds the checksum of files to the output filename. This is useful in situations where you need unique names for asset files so you can bust HTTP caches.

broccoli-rev is actually two plugins in a single module.

The first plugin (called rev) maps every file in the input tree to a file with the same name + a hash of the file's contents. For example, a file named styles/fonts.css in the input tree might be named styles/fonts-83f26306.css in the output. This step also generates a manifest file in the output that contains a map of all the original file paths to their new versions.

var rev = require('broccoli-rev');
var revvedTree = rev(myTree, {
  // The revision number or string for this build, if all files should use 
  // the same revision. If not given, the revision for a given file is the 
  // MD5 checksum of its contents. Defaults to null. 
  revision: null,
  // The length to use for the hash that is appended to the filename 
  // immediately before the file extension when using the file's checksum 
  // as its revision. Defaults to 8. 
  hashLength: 8,
  // The name of a file in the destination directory that will be created 
  // that contains a mapping of unrev'd filenames to their rev'd versions. 
  // This is useful for doing search & replace in files that reference rev'd 
  // files later on. Defaults to "/rev-manifest.json". 
  manifestFile: '/rev-manifest.json'

The second plugin in this module is optional, but represents a common use case. Basically, it takes the manifest file from the first step and interpolates its values into a Handlebars template using a rev helper function.

For example, let's say you're generating an HTML page that includes a JavaScript file that you want to manage using broccoli-rev. Your index.hbs file might look like this:

<!DOCTYPE html>
    <script src="{{ rev "built-scripts/navigation.js" }}"></script> 

You might also have a scripts directory that contains source versions of all the scripts you want to run on your HTML page. In this scenario, you could use the following Brocfile.js to build rev'd versions of the scripts and interpolate the rev'd file names into the template for index.html.

var pickFiles = require('broccoli-static-compiler');
var mergeTrees = require('broccoli-merge-trees');
var rev = require('broccoli-rev');
var indexTree = pickFiles('templates', {
  srcDir: '/',
  destDir: '/',
  files: [ 'index.hbs' ]
// scriptsTree is a rev'd version of all files in the scripts 
// source directory + the rev-manifest.json file. 
var scriptsTree = rev(pickFiles('scripts', {
  srcDir: '/',
  destDir: '/built-scripts'
var indexAndScriptsTree = mergeTrees([ indexTree, scriptsTree ]);
// Render index.hbs => index.html using a rev Handlebars helper 
// function that looks up paths in the rev-manifest.json file. 
module.exports = rev.rewriter(indexAndScriptsTree, {
  inputFile: 'index.hbs',
  outputFile: 'index.html'