Mojolicious::Plugin::AssetPack - Compress and convert css, less, sass, javascript and coffeescript files




In your application:

  use Mojolicious::Lite;

  plugin 'AssetPack';

  # define assets: $moniker => @real_assets
  app->asset('app.js' => '/js/foo.js', '/js/bar.js', '/js/');
  app->asset('app.css' => '/css/foo.less', '/css/bar.scss', '/css/main.css');

  # you can combine with assets from web
  app->asset('ie8.js' => (


In your template:

  %= asset 'app.js'
  %= asset 'app.css'

Or if you want the asset inlined in the HTML:

  %= asset 'app.css', { inline => 1 }

You can also pass on attributes to the generated HTML tag:

  %= asset 'app.css', {}, media => "print,handheld,embossed"

Or if you need to add the tags manually:

  % for my $asset (asset->get('app.js')) {
    %= javascript $asset
  % }

See also "register".


Mojolicious::Plugin::AssetPack is a Mojolicious plugin which can be used to cram multiple assets of the same type into one file. This means that if you have a lot of CSS files (.css, .less, .sass, ...) as input, the AssetPack can make one big CSS file as output. This is good, since it will often speed up the rendering of your page. The output file can even be minified, meaning you can save bandwidth and browser parsing time.

The core preprocessors that are bundled with this module can handle CSS and JavaScript files, written in many languages.

See Mojolicious::Plugin::AssetPack::Preprocessors for more details.

Production mode

This plugin will compress sass, less, css, javascript and coffeescript with the help of external applications on startup. The result will be one file with all the sources combined. This file is stored in "Packed directory".

The files in the packed directory will have a checksum added to the filename which will ensure broken browsers request a new version once the file is changed. Example:

  <script src="/packed/app-ed6d968e39843a556dbe6dad8981e3e0.js">

This is done using "process".

Development mode

This plugin will expand the input files to multiple script or link tags which makes debugging and development easier.

This is done using "expand".

TIP! Make morbo watch your less/sass files as well:

  $ morbo -w lib -w templates -w public/sass

You can also set the "MOJO_ASSETPACK_NO_CACHE" environment variable to 1 to convert your less/sass/coffee files each time their asset directive is expanded (only works when "minify" is disabled).

Inlined assets

AssetPack is able to insert your assets directly into your markup. This is useful if you want to make a one-page app and want to keep the number of requests to the server at a minimum. However, the images, fonts or any other external asset which again is referred to require more requests to the server. See below on how to include the asset directly in your template:

  %= asset 'app.css', { inline => 1 }

Or for manual inspection:

  % for my $data (asset->get('app.js', { inline => 1 })) {
    %== $data;

Custom domain

You might want to serve the assets from a domain different from where the main app is running. The reasons for that might be:

  • No cookies send on each request. This is especially useful when you use Mojolicious sessions as they are stored in cookies and clients send whole session with every request.

  • More request done in parallel. Browsers have limits for sending parallel request to one domain. With separate domain static files can be loaded in parallel.

  • Serve files directly (by absolute url) from CDN (or Amazon S3).

This plugin support this if you set a custom "base_url".

See also



Set this to get extra debug information to STDERR from AssetPack internals.


If true, convert the assets each time they're expanded, instead of once at application start (useful for development). Has no effect when "minify" is enabled.



  $self = $self->base_url("");
  $str = $self->base_url;

This attribute can be used to control where to serve static assets from. it defaults to "/packed". See also "Custom domain".

NOTE! You need to have a trailing "/" at the end of the string.


  $self = $self->fallback($bool);

Setting this attribute to true will enable the asset() helper to use bundled assets if the "process" step fail. asset() will still throw an error if there are no bundled assets available.

The default value is "1" in production mode.

This feauture is EXPERIMENTAL. Feedback wanted.


Set this to true if the assets should be minified.


Holds a Mojolicious::Plugin::AssetPack::Preprocessors object.


Holds the path to the directory where packed files can be written. It defaults to "mojo-assetpack-public/packed" directory in temp unless a static directory is writeable.



  $self->add($moniker => @rel_files);

Used to define new assets aliases. This method is called when the asset() helper is called on the app.


  $path = $self->fetch($url);

This method can be used to fetch an asset and store the content to a local file. The download will be skipped if the file already exists. The return value is the absolute path to the downloaded file.


  @files = $self->get($moniker);

Returns a list of files which the moniker point to. The list will only contain one file if the $moniker is minified.


  $self = $self->preprocessor($name => \%args);

Use this method to manually register a preprocessor.

See "SYNOPSIS" in Mojolicious::Plugin::AssetPack::Preprocessor::Browserify for example usage.


  $self->process($moniker => @files);

This method use "process" in Mojolicious::Plugin::AssetPack::Preprocessors to convert and/or minify the sources pointed at by $moniker.

The result file will be stored in "Packed directory".


  plugin AssetPack => {
    base_url => $str, # default to "/packed"
    minify => $bool, # compress assets

Will register the compress helper. All arguments are optional.

"minify" will default to true if "mode" in Mojolicious is "production".


Copyright (C) 2014, Jan Henning Thorsen.

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.


Jan Henning Thorsen -

Alexander Rymasheusky

Per Edin -

Viktor Turskyi