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Jan Henning Thorsen


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/baz.coffee');
  app->asset('app.css' => '/css/foo.less', '/css/bar.scss', '/css/main.css');

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


In your template:

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

Or if you need to add the tags manually:

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

See also "register".



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.


Production mode

This plugin will compress scss, 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).


This library tries to find default preprocessors for less, scss, js, coffee and css.

NOTE! The preprocessors require optional dependencies to function properly. Check out "detect" in Mojolicious::Plugin::AssetPack::Preprocessors for more details.

You can also define your own preprocessors:

  app->asset->preprocessors->add(js => sub {
    my($assetpack, $text, $file) = @_;
    $$text = "// yikes!\n" if 5 < rand 10;

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 https://developers.google.com/speed/docs/best-practices/request#ServeFromCookielessDomain.



  $self = $self->base_url("http://my-domain.com/static/");
  $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.


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" 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.


  $bytestream = $self->expand($c, $moniker);

This method will return one tag for each asset defined by the "$moniker".

Will also run "less", "sass" or "coffee" on the files to convert them to css or js, which the browser understands. (With "MOJO_ASSETPACK_NO_CACHE" enabled, this is done each time on expand; with it disabled, this is done once when the asset is added.)

The returning bytestream will contain style or script tags.


  @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.


  $self->process($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
    no_autodetect => $bool, # disable preprocessor autodetection

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 - jhthorsen@cpan.org

Alexander Rymasheusky

Per Edin - info@peredin.com

Viktor Turskyi