Add option to store revision as a query param instead of renaming the files

Gruntfile.js

@@ -76,6 +76,13 @@ module.exports = function (grunt) {
         cwd: 'test/fixtures',
         src: ['*.js', '*.css'],
         dest: 'test/tmp/withSourceMaps'
+      },
+      usingQueryParams: {
+        options: {
+          useQueryParam: true
+        },
+        src: ['test/fixtures/not-modified.png'],
+        dest: 'test/tmp/dest'
       }
     },
     simplemocha: {

README.md

@@ -53,6 +53,13 @@ Default: `8`
 
 The number of characters of the file hash to prefix the file name with.
 
+#### options.useQueryParam
+
+Type: `boolean`  
+Default: `false`
+
+Whether or not to use a query parameter (`?rev=XXXXXXX`) instead of actually renaming the files. This way, the files will retain their filename, but a query parameter containing the file hash can be attached and used in later references. The link to the file, including the query parameter can be found in the `grunt.filerev.summary` object and, e.g., be used in subsequent tasks like usemin.
+
 ### Destination
 
 It will overwrite the `src` files if you don't specify a `dest`:

tasks/filerev.js

@@ -12,7 +12,8 @@ module.exports = function (grunt) {
     var filerev = grunt.filerev || {summary: {}};
     var options = this.options({
       algorithm: 'md5',
-      length: 8
+      length: 8,
+      useQueryParam: false
     });
 
     eachAsync(this.files, function (el, i, next) {
@@ -50,14 +51,19 @@ module.exports = function (grunt) {
         var ext = path.extname(file);
         var newName;
 
-        if (typeof options.process === 'function') {
-          newName = options.process(path.basename(file, ext), suffix, ext.slice(1));
-        } else {
-          if (options.process) {
-            grunt.log.error('options.process must be a function; ignoring');
-          }
+        if (!options.useQueryParam) {
+          if (typeof options.process === 'function') {
+            newName = options.process(path.basename(file, ext), suffix, ext.slice(1));
+          } else {
+            if (options.process) {
+              grunt.log.error('options.process must be a function; ignoring');
+            }
 
-          newName = [path.basename(file, ext), suffix, ext.slice(1)].join('.');
+            newName = [path.basename(file, ext), suffix, ext.slice(1)].join('.');
+          }
+        } else {
+          // no renaming but the hash can be used to bust caches by appending it as a query parameter
+          newName = [path.basename(file, ext), ext.slice(1)].join('.');
         }
 
         var resultPath;
@@ -102,6 +108,10 @@ module.exports = function (grunt) {
         }
 
         filerev.summary[path.normalize(file)] = path.join(dirname, newName);
+        // if using the useQueryParam method, append the queryString
+        if (options.useQueryParam) {
+          filerev.summary[path.normalize(file)] += '?rev=' + suffix;
+        }
         grunt.verbose.writeln(chalk.green('✔ ') + file + chalk.gray(' changed to ') + newName);
 
         if (sourceMap) {

test/test.js

@@ -12,7 +12,8 @@ var hashes = {
   'test/fixtures/styles.css.map' : 'test/tmp/withSourceMaps/styles.a6aa2292.css.map',
   'test/fixtures/more-styles.css' : 'test/tmp/withSourceMaps/more-styles.dce8e0e5.css',
   'test/fixtures/inline.js' : 'test/tmp/withSourceMaps/inline.8b435ef2.js',
-  'test/fixtures/another.png' : 'test/tmp/another-processed-92279d3f.png'
+  'test/fixtures/another.png' : 'test/tmp/another-processed-92279d3f.png',
+  'test/fixtures/not-modified.png' : 'test/tmp/not-modified.png'
 };
 
 it('should revision files based on content', function () {
@@ -98,3 +99,10 @@ it('should allow a filename processing function', function () {
   var revisioned = fs.statSync(hashes[file]).size;
   assert(revisioned === original);
 });
+
+it('should not rename files with the useQueryParam option', function () {
+  var file = 'test/fixtures/not-modified.png';
+  var original = fs.statSync(file).size;
+  var revisioned = fs.statSync(hashes[file]).size;
+  assert(revisioned === original);
+});