# gulp-rev [](https://travis-ci.org/sindresorhus/gulp-rev) [](https://github.com/sindresorhus/xo) [](https://gitter.im/sindresorhus/gulp-rev)
> Static asset revisioning by appending content hash to filenames
> `unicorn.css` → `unicorn-d41d8cd98f.css`
**This project is feature complete.**
Make sure to set the files to [never expire](http://developer.yahoo.com/performance/rules.html#expires) for this to have an effect.
---
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---
## Install
```
$ npm install --save-dev gulp-rev
```
## Usage
```js
const gulp = require('gulp');
const rev = require('gulp-rev');
gulp.task('default', () =>
gulp.src('src/*.css')
.pipe(rev())
.pipe(gulp.dest('dist'))
);
```
## API
### rev()
### rev.manifest([path], [options])
#### path
Type: `string`
Default: `rev-manifest.json`
Manifest file path.
#### options
##### base
Type: `string`
Default: `process.cwd()`
Override the `base` of the manifest file.
##### cwd
Type: `string`
Default: `process.cwd()`
Override the current working directory of the manifest file.
##### merge
Type: `boolean`
Default: `false`
Merge existing manifest file.
##### transformer
Type: `object`
Default: `JSON`
An object with `parse` and `stringify` methods. This can be used to provide a
custom transformer instead of the default `JSON` for the manifest file.
### Original path
Original file paths are stored at `file.revOrigPath`. This could come in handy for things like rewriting references to the assets.
### Asset hash
The hash of each rev'd file is stored at `file.revHash`. You can use this for customizing the file renaming, or for building different manifest formats.
### Asset manifest
```js
const gulp = require('gulp');
const rev = require('gulp-rev');
gulp.task('default', () =>
// by default, gulp would pick `assets/css` as the base,
// so we need to set it explicitly:
gulp.src(['assets/css/*.css', 'assets/js/*.js'], {base: 'assets'})
.pipe(gulp.dest('build/assets')) // copy original assets to build dir
.pipe(rev())
.pipe(gulp.dest('build/assets')) // write rev'd assets to build dir
.pipe(rev.manifest())
.pipe(gulp.dest('build/assets')) // write manifest to build dir
);
```
An asset manifest, mapping the original paths to the revisioned paths, will be written to `build/assets/rev-manifest.json`:
```json
{
"css/unicorn.css": "css/unicorn-d41d8cd98f.css",
"js/unicorn.js": "js/unicorn-273c2c123f.js"
}
```
By default, `rev-manifest.json` will be replaced as a whole. To merge with an existing manifest, pass `merge: true` and the output destination (as `base`) to `rev.manifest()`:
```js
const gulp = require('gulp');
const rev = require('gulp-rev');
gulp.task('default', () =>
// by default, gulp would pick `assets/css` as the base,
// so we need to set it explicitly:
gulp.src(['assets/css/*.css', 'assets/js/*.js'], {base: 'assets'})
.pipe(gulp.dest('build/assets'))
.pipe(rev())
.pipe(gulp.dest('build/assets'))
.pipe(rev.manifest({
base: 'build/assets',
merge: true // merge with the existing manifest if one exists
}))
.pipe(gulp.dest('build/assets'))
);
```
You can optionally call `rev.manifest('manifest.json')` to give it a different path or filename.
## Sourcemaps and `gulp-concat`
Because of the way `gulp-concat` handles file paths, you may need to set `cwd` and `path` manually on your `gulp-concat` instance to get everything to work correctly:
```js
const gulp = require('gulp');
const rev = require('gulp-rev');
const sourcemaps = require('gulp-sourcemaps');
const concat = require('gulp-concat');
gulp.task('default', () =>
gulp.src('src/*.js')
.pipe(sourcemaps.init())
.pipe(concat({path: 'bundle.js', cwd: ''}))
.pipe(rev())
.pipe(sourcemaps.write('.'))
.pipe(gulp.dest('dist'))
)
```
## Different hash for unchanged files
Since the order of streams are not guaranteed, some plugins such as `gulp-concat` can cause the final file's content and hash to change. To avoid generating a new hash for unchanged source files, you can:
- Sort the streams with [gulp-sort](https://github.com/pgilad/gulp-sort)
- Filter unchanged files with [gulp-unchanged](https://github.com/sindresorhus/gulp-changed)
- Read more about [incremental builds](https://github.com/gulpjs/gulp#incremental-builds)
## Streaming
This plugin does not support streaming. If you have files from a streaming source, such as Browserify, you should use [`gulp-buffer`](https://github.com/jeromew/gulp-buffer) before `gulp-rev` in your pipeline:
```js
const gulp = require('gulp');
const browserify = require('browserify');
const source = require('vinyl-source-stream');
const buffer = require('gulp-buffer');
const rev = require('gulp-rev');
gulp.task('default', () =>
browserify('src/index.js')
.bundle({debug: true})
.pipe(source('index.min.js'))
.pipe(buffer())
.pipe(rev())
.pipe(gulp.dest('dist'))
);
```
## Integration
For more info on how to integrate `gulp-rev` into your app, have a look at the [integration guide](integration.md).
## Use gulp-rev in combination with one or more of
It may be useful - and necessary - to use `gulp-rev` with other packages to complete the task.
- [gulp-rev-replace](https://github.com/jamesknelson/gulp-rev-replace) - Rewrite occurences of filenames which have been renamed
- [gulp-rev-css-url](https://github.com/galkinrost/gulp-rev-css-url) - Override URLs in CSS files with the revved ones
- [gulp-rev-outdated](https://github.com/shonny-ua/gulp-rev-outdated) - Old static asset revision files filter
- [gulp-rev-collector](https://github.com/shonny-ua/gulp-rev-collector) - Static asset revision data collector
- [rev-del](https://github.com/callumacrae/rev-del) - Delete old unused assets
- [gulp-rev-delete-original](https://github.com/nib-health-funds/gulp-rev-delete-original) - Delete original files after rev
- [gulp-rev-loader](https://github.com/adjavaherian/gulp-rev-loader) - Use rev-manifest with webpack
- [gulp-rev-format](https://github.com/atamas101/gulp-rev-format) - Provide hash formatting options for static assets (prefix, suffix, last-extension)
## Maintainers
- [Sindre Sorhus](https://sindresorhus.com)
- [Justin Hileman](http://justinhileman.info)
- [Ben Bieler](https://github.com/benbieler)
- [Gabin Aureche](https://gabinaureche.com)
## License
MIT © [Sindre Sorhus](https://sindresorhus.com)