Docs: Add recipe for static asset revisioning

Author: silvenon

docs/recipes/README.md

@@ -28,3 +28,4 @@
 * [Rollup with rollup-stream](rollup-with-rollup-stream.md)
 * [Run gulp task via cron job](cron-task.md)
 * [Running shell commands](running-shell-commands.md)
+* [Static asset revisioning](static-asset-revisioning.md)

docs/recipes/static-asset-revisioning.md

@@ -0,0 +1,33 @@
+# Static asset revisioning
+
+Static asset revisioning by appending content hash to filenames. Make sure to set the files to [never expire](http://developer.yahoo.com/performance/rules.html#expires) for this to have an effect.
+
+```sh
+npm install --save-dev gulp gulp-rev gulp-rev-rewrite gulp-rev-delete-original
+```
+
+```js
+const gulp = require('gulp')
+const rev = require('gulp-rev')
+const revRewrite = require('gulp-rev-rewrite')
+const revDelOriginal = require('gulp-rev-delete-original')
+
+function revisionAssets() {
+  return gulp
+    // add assets you want to revision
+    .src(`dist/**/*.{css,js}`)
+    // append conent hash
+    .pipe(rev())
+    // delete original (unrevved) assets from "dist"
+    .pipe(revDelOriginal())
+    // add files that contain references to those assets
+    // now we have revved assets and HTML files in the stream
+    .pipe(gulp.src(`dist/**/*.html`))
+    // update references to the assets
+    .pipe(revRewrite())
+    // output revved assets along with HTML files with updated references
+    .pipe(gulp.dest('dist'))
+}
+
+exports.revisionAssets = revisionAssets
+```