module Sprockets::Engines

`Engines` provides a global and `Environment` instance registry.

An engine is a type of processor that is bound to a filename extension. `application.js.coffee` indicates that the `CoffeeScriptProcessor` engine will be ran on the file.

Extensions can be stacked and will be evaulated from right to left. `application.js.coffee.erb` will first run `ERBProcessor` then `CoffeeScriptProcessor`.

All `Engine`s must follow the `Template` interface. It is recommended to subclass `Template`.

Its recommended that you register engine changes on your local `Environment` instance.

environment.register_engine '.foo', FooProcessor

The global registry is exposed for plugins to register themselves.

Sprockets.register_engine '.sass', SassProcessor

Public Instance Methods

engine_mime_types() click to toggle source

Internal: Returns a `Hash` of engine extensions to mime types.

# => { '.coffee' => 'application/javascript' }

# File lib/sprockets/engines.rb, line 44
def engine_mime_types
  config[:engine_mime_types]
end
engines() click to toggle source

Returns a `Hash` of `Engine`s registered on the `Environment`. If an `ext` argument is supplied, the `Engine` associated with that extension will be returned.

environment.engines
# => {".coffee" => CoffeeScriptProcessor, ".sass" => SassProcessor, ...}
# File lib/sprockets/engines.rb, line 37
def engines
  config[:engines]
end
register_engine(ext, klass, options = {}) click to toggle source

Registers a new Engine `klass` for `ext`. If the `ext` already has an engine registered, it will be overridden.

environment.register_engine '.coffee', CoffeeScriptProcessor
# File lib/sprockets/engines.rb, line 53
    def register_engine(ext, klass, options = {})
      unless options[:silence_deprecation]
        msg = <<-MSG
Sprockets method `register_engine` is deprecated.
Please register a mime type using `register_mime_type` then
use `register_compressor` or `register_transformer`.
https://github.com/rails/sprockets/blob/master/guides/extending_sprockets.md#supporting-all-versions-of-sprockets-in-processors
        MSG

        Deprecation.new([caller.first]).warn(msg)
      end

      ext = Sprockets::Utils.normalize_extension(ext)

      self.computed_config = {}

      if klass.respond_to?(:call)
        processor = klass
        self.config = hash_reassoc(config, :engines) do |engines|
          engines.merge(ext => klass)
        end
        if options[:mime_type]
          self.config = hash_reassoc(config, :engine_mime_types) do |mime_types|
            mime_types.merge(ext.to_s => options[:mime_type])
          end
        end
      else
        processor = LegacyTiltProcessor.new(klass)
        self.config = hash_reassoc(config, :engines) do |engines|
          engines.merge(ext => processor)
        end
        if klass.respond_to?(:default_mime_type) && klass.default_mime_type
          self.config = hash_reassoc(config, :engine_mime_types) do |mime_types|
            mime_types.merge(ext.to_s => klass.default_mime_type)
          end
        end
      end
    end