asset-revisioning.md

Asset revisioning

This recipe demonstrates how to set up simple static asset revisioning (aka revving) for CSS and JS by appending content hash to their filenames unicorn.css → unicorn-098f6bcd.css.

Make sure to set the files to never expire for this to have an effect.

Steps

1. Install dependencies

Install these gulp plugins:

$ npm install --save-dev gulp-rev gulp-rev-replace

• gulp-rev appends content hashes
• gulp-rev-replace updates references to those files

2. Update the html task

Instead of wasting performance reading CSS and JS files into a new stream, we can notice that we already have that stream available in the html task, so we can just perform revving there:

gulp.task('html', ['styles'], function () {
  var assets = $.useref.assets({searchPath: ['.tmp', 'app', '.']});

  return gulp.src('app/*.html')
    .pipe(assets)
    .pipe($.if('*.js', $.uglify()))
    .pipe($.if('*.css', $.csso()))
+   .pipe($.rev())
    .pipe(assets.restore())
    .pipe($.useref())
+   .pipe($.revReplace())
    .pipe($.if('*.html', $.minifyHtml({conditionals: true, loose: true})))
    .pipe(gulp.dest('dist'));
});

• .pipe($.rev()) – at this point we have CSS and JS files in the stream, so we are revving them
• .pipe($.revReplace()) – at this point we have CSS, JS and HTML files in the stream, so we are updating all references to revved files