# gulp-manifest
> Generate HTML5 Cache Manifest files. Submitted by [Scott Hillman](https://github.com/hillmanov/).

Big thanks to [Gunther Brunner](https://github.com/gunta/) for writing the [grunt-manifest](https://github.com/gunta/grunt-manifest) plugin. This plugin was heavily influenced by his great work.

Visit the [HTML 5 Guide to AppCache](http://www.html5rocks.com/en/tutorials/appcache/beginner/) for more information on Cache Manifest files.

## Usage

First, install `gulp-manifest` as a dev dependency

```shell
npm install gulp-manifest --save-dev
```

## API

### Parameters

### manifest(options)

This controls how this task (and its helpers) operate and should contain key:value pairs, see options below.

#### options.prefix
Type: `String`
Default: `undefined`

Add a prefix to the file paths. Useful when your files are in a different URL than the page.

#### options.suffix
Type: `String`  
Default: `undefined`  

Add a suffix to the file paths. Useful when your files have query string.

#### options.filename
Type: `String`
Default: `'app.manifest'`

Set name of the Cache Manifest file.

#### options.cache
Type: `String` `Array`
Default: `undefined`

Adds manually a string to the **CACHE** section. Needed when you have cache buster for example.

#### options.exclude
Type: `String` `Array`
Default: `undefined`

Exclude specific files from the Cache Manifest file.

#### options.network
Type: `String` `Array`
Default: `'*'` (By default, an online whitelist wildcard flag is added)

Adds a string to the **NETWORK** section.

See [here](http://diveintohtml5.info/offline.html#network) for more information.

#### options.fallback
Type: `String` `Array`
Default: `undefined`

Adds a string to the **FALLBACK** section.

See [here](http://diveintohtml5.info/offline.html#fallback) for more information.

#### options.preferOnline
Type: `Boolean`
Default: `undefined`

Adds a string to the **SETTINGS** section, specifically the cache mode flag of the ```prefer-online``` state.

See [here](http://www.whatwg.org/specs/web-apps/current-work/multipage/offline.html#concept-appcache-mode-prefer-online) for more information.

#### options.timestamp
Type: `Boolean`
Default: `true`

Adds a timestamp as a comment for easy versioning.

Note: timestamp will invalidate application cache whenever cache manifest is rebuilt, even if contents of files in `src` have not changed.

#### options.hash
Type: `Boolean`
Default: `false`

Adds a sha256 hash of all `src` files (actual contents) as a comment.

This will ensure that application cache invalidates whenever actual file contents change (it's recommented to set `timestamp` to `false` when `hash` is used).

### Usage Example


    gulp.task('manifest', function(){
      gulp.src(['build/*'], { base: './' })
        .pipe(manifest({
          hash: true,
          preferOnline: true,
          network: ['*'],
          filename: 'app.manifest',
          exclude: 'app.manifest'
         }))
        .pipe(gulp.dest('build'));
    });


### Output example

```
  CACHE MANIFEST

  CACHE:
  js/app.js
  css/style
  css/style.css
  js/zepto.min.js
  js/script.js
  some_files/index.html
  some_files/about.html

  NETWORK:
  *

  # hash: 76f0ef591f999871e1dbdf6d5064d1276d80846feeef6b556f74ad87b44ca16a
```

You do need to be fully aware of standard browser caching.
If the files in **CACHE** are in the network cache, they won't actually update,
since the network cache will spit back the same file to the application cache.
Therefore, it's recommended to add a hash to the filenames's, akin to rails or yeoman. See [here](http://www.stevesouders.com/blog/2008/08/23/revving-filenames-dont-use-querystring/) why query strings are not recommended.

### Composition of paths

Sometimes your assets are served from different source directories. To route these correctly the `gulp.src.base` option can be used to [define a glob's base path](https://github.com/gulpjs/gulp/blob/master/docs/API.md#optionsbase). Later multiple streams can be composed with [merge-stream](https://github.com/grncdr/merge-stream), so that one single manifest file is created from them

```javascript
var path = require('path');
var mergeStream = require('merge-stream');

var config = {
  app: './app',
  tmp: './tmp'
};

mergeStream(
  gulp.src([
    path.join(config.app + '*.html'),
    path.join(config.app + 'assets/*.{png,svg,jpg}'),
    path.join(config.app + 'js/*.js')
  ], {
    base: config.app
  }),
  gulp.src([
  	path.join(config.tmp + 'css/*.css')
  ], {
    base: config.tmp
  })
);
.pipe(plugins.manifest({
  hash: true,
  preferOnline: false,
  network: ['*'],
  filename: 'appcache.manifest'
}))
.pipe(gulp.dest(config.tmp));
```

for the given file tree

```
├── app
│   ├── assets
│   │   ├── cover.png
│   │   └── logo.svg
│   ├── index.html
│   ├── js
│   │   └── script.js
│   └── scss
│       └── style.scss
└── tmp
    └── css
        └── style.css
```

will result in

```
index.html
assets/cover.png
assets/logo.svg
js/script.js
css/style.css
```

Sometimes you might want to alter the way paths are passed to the plugin. The correct way will be to provide options to `gulp.src` so that it generates correct paths.

Say, you have a single folder named `public`, which is the top-level directory that's served to the browser. In the same directory, you have the `css`, `js` and `asset` files under different directories, along with the `html` files.

```
public/
├── assets
│   ├── cover.png
│   └── logo.png
├── css
│   └── style.css
├── js
│   └── app.js
└── index.html
```