assetgen 0.1

Asset generator for modern web app development

Assetgen is intended as a replacement for the various ad-hoc scripts that often get written to build/manage JavaScript/CSS files.

Features

The default support includes:

• Compiling CoffeeScript source files into JavaScript.

• Minifying JavaScript through UglifyJS – including the new constant folding support.

• Compiling and minifying SASS stylesheets into CSS.

• Generating variants of the same stylesheet for both internationalisation (flipping left to right) and for automatically embedding images as data: URIs to minimise latency.

• Concatenating multiple source files into one file to minimise the number of HTTP requests.

• Creating distinct files with the hash of the content embedded in the filename so as to work effectively with web caches.

• Creating a JSON manifest file for use in your web app’s static handlers.

The tool is driven by the configuration you specify in an assetgen.yaml file, e.g.

# Example assetgen.yaml configuration

generate:

- js/base.js:
    source:
      - %(AMPIFY_ROOT)s/third_party/jslibs/json.js

- js/app.js:
    source:
      - static/js/Models.coffee
      - static/js/Views.coffee
      - static/js/Maps.coffee
    uglify:
      - --define-from-module
      - consts
    profile.dev:
      uglify:
        - --define-from-module
        - consts-dev

- gfx/*:
    source: static/gfx/*
    type: binary

- css/site.css:
    source:
      - raw: |
          // Public Domain (-) 2011 The Ampify Authors.
          // See the Ampify UNLICENSE file for details.
      - static/css/site.sass
    depends:
      - static/css/*.sass
      - static/gfx/*
    bidi: true
    embed.path.root: static
    embed.url.base: /.static/

prereqs:

- static/js/consts.js:
    source: static/js/consts.coffee
    compressed: false

- static/js/consts-dev.js:
    source: static/js/consts-dev.coffee
    compressed: false

env:
  NODE_PATH.prefix: static/js

output.directory: appengine/static
output.hashed: true
output.manifest: appengine/assets.json

profile.dev:
  css.compressed: false
  js.compressed: false

You can even control which config options gets used by specifying the --profile parameter. This will override default values with the values specified for the given profile. So, in the above example, specifying --profile dev will use all the profile.dev options.

And, finally, you can specify custom handlers for assetgen to call when generating a file of a given type. For example, to override the builtin js handler with one which just lower-cases all the source content, create your extension, e.g. kickass-extension.py:

class KickassAsset(Asset):

    def generate(self):
        content = ''.join(read(source).lower() for source in self.sources)
        self.emit(self.path, content)

register_handler('js', KickassAsset)

Then run assetgen with the --extension path/to/kickass-extension.py parameter specified.

Usage

Usage: assetgen [<path/to/assetgen.yaml> ...] [options]

Note:
    If you don't specify assetgen.yaml file paths, then `git
    ls-files *assetgen.yaml` will be used to detect all config
    files in the current repository. So you need to be inside
    a git repository's working tree.

Options:
  -h, --help        show this help message and exit
  -v, --version     show program's version number and exit
  --clean           remove all generated files
  --debug           set debug mode
  --extension=PATH  specify a python extension file (may be repeated)
  --force           force rebuild of all files
  --profile=NAME    specify a profile to use
  --watch           keep running assetgen on a loop

Contribute

To contribute any patches simply fork the repository using GitHub and send a pull request to https://github.com/tav, thanks!

License

All of the code has been released into the Public Domain. Do with it as you please.

– Enjoy, tav <[e-mail]>