Chris@909: # The engines plugin makes it trivial to share public assets using plugins. 
Chris@909: # To do this, include an <tt>assets</tt> directory within your plugin, and put
Chris@909: # your javascripts, stylesheets and images in subdirectories of that folder:
Chris@909: #
Chris@909: #   my_plugin
Chris@909: #     |- init.rb
Chris@909: #     |- lib/
Chris@909: #     |- assets/
Chris@909: #          |- javascripts/
Chris@909: #          |    |- my_functions.js
Chris@909: #          |
Chris@909: #          |- stylesheets/
Chris@909: #          |    |- my_styles.css
Chris@909: #          |
Chris@909: #          |- images/
Chris@909: #               |- my_face.jpg
Chris@909: #
Chris@909: # Files within the <tt>asset</tt> structure are automatically mirrored into
Chris@909: # a publicly-accessible folder each time your application starts (see
Chris@909: # Engines::Assets#mirror_assets).
Chris@909: #
Chris@909: #
Chris@909: # == Using plugin assets in views
Chris@909: #
Chris@909: # It's also simple to use Rails' helpers in your views to use plugin assets.
Chris@909: # The default helper methods have been enhanced by the engines plugin to accept
Chris@909: # a <tt>:plugin</tt> option, indicating the plugin containing the desired asset.
Chris@909: #
Chris@909: # For example, it's easy to use plugin assets in your layouts:
Chris@909: #
Chris@909: #   <%= stylesheet_link_tag "my_styles", :plugin => "my_plugin", :media => "screen" %>
Chris@909: #   <%= javascript_include_tag "my_functions", :plugin => "my_plugin" %>
Chris@909: # 
Chris@909: # ... and similarly in views and partials, it's easy to use plugin images:
Chris@909: #
Chris@909: #   <%= image_tag "my_face", :plugin => "my_plugin" %>
Chris@909: #   <!-- or -->
Chris@909: #   <%= image_path "my_face", :plugin => "my_plugin" %>
Chris@909: #
Chris@909: # Where the default helpers allow the specification of more than one file (i.e. the
Chris@909: # javascript and stylesheet helpers), you can do similarly for multiple assets from 
Chris@909: # within a single plugin.
Chris@909: #
Chris@909: # ---
Chris@909: #
Chris@909: # This module enhances four of the methods from ActionView::Helpers::AssetTagHelper:
Chris@909: #
Chris@909: #  * stylesheet_link_tag
Chris@909: #  * javascript_include_tag
Chris@909: #  * image_path
Chris@909: #  * image_tag
Chris@909: #
Chris@909: # Each one of these methods now accepts the key/value pair <tt>:plugin => "plugin_name"</tt>,
Chris@909: # which can be used to specify the originating plugin for any assets.
Chris@909: #
Chris@909: module Engines::RailsExtensions::AssetHelpers
Chris@909:   def self.included(base) #:nodoc:
Chris@909:     base.class_eval do
Chris@909:       [:stylesheet_link_tag, :javascript_include_tag, :image_path, :image_tag].each do |m|
Chris@909:         alias_method_chain m, :engine_additions
Chris@909:       end
Chris@909:     end
Chris@909:   end
Chris@909: 
Chris@909:   # Adds plugin functionality to Rails' default stylesheet_link_tag method.
Chris@909:   def stylesheet_link_tag_with_engine_additions(*sources)
Chris@909:     stylesheet_link_tag_without_engine_additions(*Engines::RailsExtensions::AssetHelpers.pluginify_sources("stylesheets", *sources))
Chris@909:   end
Chris@909: 
Chris@909:   # Adds plugin functionality to Rails' default javascript_include_tag method.  
Chris@909:   def javascript_include_tag_with_engine_additions(*sources)
Chris@909:     javascript_include_tag_without_engine_additions(*Engines::RailsExtensions::AssetHelpers.pluginify_sources("javascripts", *sources))
Chris@909:   end
Chris@909: 
Chris@909:   #--
Chris@909:   # Our modified image_path now takes a 'plugin' option, though it doesn't require it
Chris@909:   #++
Chris@909: 
Chris@909:   # Adds plugin functionality to Rails' default image_path method.
Chris@909:   def image_path_with_engine_additions(source, options={})
Chris@909:     options.stringify_keys!
Chris@909:     source = Engines::RailsExtensions::AssetHelpers.plugin_asset_path(options["plugin"], "images", source) if options["plugin"]
Chris@909:     image_path_without_engine_additions(source)
Chris@909:   end
Chris@909: 
Chris@909:   # Adds plugin functionality to Rails' default image_tag method.
Chris@909:   def image_tag_with_engine_additions(source, options={})
Chris@909:     options.stringify_keys!
Chris@909:     if options["plugin"]
Chris@909:       source = Engines::RailsExtensions::AssetHelpers.plugin_asset_path(options["plugin"], "images", source)
Chris@909:       options.delete("plugin")
Chris@909:     end
Chris@909:     image_tag_without_engine_additions(source, options)
Chris@909:   end
Chris@909: 
Chris@909:   #--
Chris@909:   # The following are methods on this module directly because of the weird-freaky way
Chris@909:   # Rails creates the helper instance that views actually get
Chris@909:   #++
Chris@909: 
Chris@909:   # Convert sources to the paths for the given plugin, if any plugin option is given
Chris@909:   def self.pluginify_sources(type, *sources)
Chris@909:     options = sources.last.is_a?(Hash) ? sources.pop.stringify_keys : { }
Chris@909:     sources.map! { |s| plugin_asset_path(options["plugin"], type, s) } if options["plugin"]
Chris@909:     options.delete("plugin") # we don't want it appearing in the HTML
Chris@909:     sources << options # re-add options      
Chris@909:   end  
Chris@909: 
Chris@909:   # Returns the publicly-addressable relative URI for the given asset, type and plugin
Chris@909:   def self.plugin_asset_path(plugin_name, type, asset)
Chris@909:     raise "No plugin called '#{plugin_name}' - please use the full name of a loaded plugin." if Engines.plugins[plugin_name].nil?
Chris@909:     "#{ActionController::Base.relative_url_root}/#{Engines.plugins[plugin_name].public_asset_directory}/#{type}/#{asset}"
Chris@909:   end
Chris@909:   
Chris@909: end
Chris@909: 
Chris@909: module ::ActionView::Helpers::AssetTagHelper #:nodoc:
Chris@909:   include Engines::RailsExtensions::AssetHelpers
Chris@909: end