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+require 'zlib'
+
+module ActionView
+ # = Action View Asset URL Helpers
+ module Helpers
+ # This module provides methods for generating asset paths and
+ # urls.
+ #
+ # image_path("rails.png")
+ # # => "/assets/rails.png"
+ #
+ # image_url("rails.png")
+ # # => "http://www.example.com/assets/rails.png"
+ #
+ # === Using asset hosts
+ #
+ # By default, Rails links to these assets on the current host in the public
+ # folder, but you can direct Rails to link to assets from a dedicated asset
+ # server by setting <tt>ActionController::Base.asset_host</tt> in the application
+ # configuration, typically in <tt>config/environments/production.rb</tt>.
+ # For example, you'd define <tt>assets.example.com</tt> to be your asset
+ # host this way, inside the <tt>configure</tt> block of your environment-specific
+ # configuration files or <tt>config/application.rb</tt>:
+ #
+ # config.action_controller.asset_host = "assets.example.com"
+ #
+ # Helpers take that into account:
+ #
+ # image_tag("rails.png")
+ # # => <img alt="Rails" src="http://assets.example.com/assets/rails.png" />
+ # stylesheet_link_tag("application")
+ # # => <link href="http://assets.example.com/assets/application.css" media="screen" rel="stylesheet" />
+ #
+ # Browsers typically open at most two simultaneous connections to a single
+ # host, which means your assets often have to wait for other assets to finish
+ # downloading. You can alleviate this by using a <tt>%d</tt> wildcard in the
+ # +asset_host+. For example, "assets%d.example.com". If that wildcard is
+ # present Rails distributes asset requests among the corresponding four hosts
+ # "assets0.example.com", ..., "assets3.example.com". With this trick browsers
+ # will open eight simultaneous connections rather than two.
+ #
+ # image_tag("rails.png")
+ # # => <img alt="Rails" src="http://assets0.example.com/assets/rails.png" />
+ # stylesheet_link_tag("application")
+ # # => <link href="http://assets2.example.com/assets/application.css" media="screen" rel="stylesheet" />
+ #
+ # To do this, you can either setup four actual hosts, or you can use wildcard
+ # DNS to CNAME the wildcard to a single asset host. You can read more about
+ # setting up your DNS CNAME records from your ISP.
+ #
+ # Note: This is purely a browser performance optimization and is not meant
+ # for server load balancing. See http://www.die.net/musings/page_load_time/
+ # for background.
+ #
+ # Alternatively, you can exert more control over the asset host by setting
+ # +asset_host+ to a proc like this:
+ #
+ # ActionController::Base.asset_host = Proc.new { |source|
+ # "http://assets#{Digest::MD5.hexdigest(source).to_i(16) % 2 + 1}.example.com"
+ # }
+ # image_tag("rails.png")
+ # # => <img alt="Rails" src="http://assets1.example.com/assets/rails.png" />
+ # stylesheet_link_tag("application")
+ # # => <link href="http://assets2.example.com/assets/application.css" media="screen" rel="stylesheet" />
+ #
+ # The example above generates "http://assets1.example.com" and
+ # "http://assets2.example.com". This option is useful for example if
+ # you need fewer/more than four hosts, custom host names, etc.
+ #
+ # As you see the proc takes a +source+ parameter. That's a string with the
+ # absolute path of the asset, for example "/assets/rails.png".
+ #
+ # ActionController::Base.asset_host = Proc.new { |source|
+ # if source.ends_with?('.css')
+ # "http://stylesheets.example.com"
+ # else
+ # "http://assets.example.com"
+ # end
+ # }
+ # image_tag("rails.png")
+ # # => <img alt="Rails" src="http://assets.example.com/assets/rails.png" />
+ # stylesheet_link_tag("application")
+ # # => <link href="http://stylesheets.example.com/assets/application.css" media="screen" rel="stylesheet" />
+ #
+ # Alternatively you may ask for a second parameter +request+. That one is
+ # particularly useful for serving assets from an SSL-protected page. The
+ # example proc below disables asset hosting for HTTPS connections, while
+ # still sending assets for plain HTTP requests from asset hosts. If you don't
+ # have SSL certificates for each of the asset hosts this technique allows you
+ # to avoid warnings in the client about mixed media.
+ #
+ # config.action_controller.asset_host = Proc.new { |source, request|
+ # if request.ssl?
+ # "#{request.protocol}#{request.host_with_port}"
+ # else
+ # "#{request.protocol}assets.example.com"
+ # end
+ # }
+ #
+ # You can also implement a custom asset host object that responds to +call+
+ # and takes either one or two parameters just like the proc.
+ #
+ # config.action_controller.asset_host = AssetHostingWithMinimumSsl.new(
+ # "http://asset%d.example.com", "https://asset1.example.com"
+ # )
+ #
+ module AssetUrlHelper
+ URI_REGEXP = %r{^[-a-z]+://|^(?:cid|data):|^//}i
+
+ # Computes the path to asset in public directory. If :type
+ # options is set, a file extension will be appended and scoped
+ # to the corresponding public directory.
+ #
+ # All other asset *_path helpers delegate through this method.
+ #
+ # asset_path "application.js" # => /application.js
+ # asset_path "application", type: :javascript # => /javascripts/application.js
+ # asset_path "application", type: :stylesheet # => /stylesheets/application.css
+ # asset_path "http://www.example.com/js/xmlhr.js" # => http://www.example.com/js/xmlhr.js
+ def asset_path(source, options = {})
+ source = source.to_s
+ return "" unless source.present?
+ return source if source =~ URI_REGEXP
+
+ tail, source = source[/([\?#].+)$/], source.sub(/([\?#].+)$/, '')
+
+ if extname = compute_asset_extname(source, options)
+ source = "#{source}#{extname}"
+ end
+
+ if source[0] != ?/
+ source = compute_asset_path(source, options)
+ end
+
+ relative_url_root = defined?(config.relative_url_root) && config.relative_url_root
+ if relative_url_root
+ source = "#{relative_url_root}#{source}" unless source.starts_with?("#{relative_url_root}/")
+ end
+
+ if host = compute_asset_host(source, options)
+ source = "#{host}#{source}"
+ end
+
+ "#{source}#{tail}"
+ end
+ alias_method :path_to_asset, :asset_path # aliased to avoid conflicts with a asset_path named route
+
+ # Computes the full URL to a asset in the public directory. This
+ # will use +asset_path+ internally, so most of their behaviors
+ # will be the same.
+ def asset_url(source, options = {})
+ path_to_asset(source, options.merge(:protocol => :request))
+ end
+ alias_method :url_to_asset, :asset_url # aliased to avoid conflicts with an asset_url named route
+
+ ASSET_EXTENSIONS = {
+ javascript: '.js',
+ stylesheet: '.css'
+ }
+
+ # Compute extname to append to asset path. Returns nil if
+ # nothing should be added.
+ def compute_asset_extname(source, options = {})
+ return if options[:extname] == false
+ extname = options[:extname] || ASSET_EXTENSIONS[options[:type]]
+ extname if extname && File.extname(source) != extname
+ end
+
+ # Maps asset types to public directory.
+ ASSET_PUBLIC_DIRECTORIES = {
+ audio: '/audios',
+ font: '/fonts',
+ image: '/images',
+ javascript: '/javascripts',
+ stylesheet: '/stylesheets',
+ video: '/videos'
+ }
+
+ # Computes asset path to public directory. Plugins and
+ # extensions can override this method to point to custom assets
+ # or generate digested paths or query strings.
+ def compute_asset_path(source, options = {})
+ dir = ASSET_PUBLIC_DIRECTORIES[options[:type]] || ""
+ File.join(dir, source)
+ end
+
+ # Pick an asset host for this source. Returns +nil+ if no host is set,
+ # the host if no wildcard is set, the host interpolated with the
+ # numbers 0-3 if it contains <tt>%d</tt> (the number is the source hash mod 4),
+ # or the value returned from invoking call on an object responding to call
+ # (proc or otherwise).
+ def compute_asset_host(source = "", options = {})
+ request = self.request if respond_to?(:request)
+ host = config.asset_host if defined? config.asset_host
+ host ||= request.base_url if request && options[:protocol] == :request
+
+ if host.respond_to?(:call)
+ arity = host.respond_to?(:arity) ? host.arity : host.method(:call).arity
+ args = [source]
+ args << request if request && (arity > 1 || arity < 0)
+ host = host.call(*args)
+ elsif host =~ /%d/
+ host = host % (Zlib.crc32(source) % 4)
+ end
+
+ return unless host
+
+ if host =~ URI_REGEXP
+ host
+ else
+ protocol = options[:protocol] || config.default_asset_host_protocol || (request ? :request : :relative)
+ case protocol
+ when :relative
+ "//#{host}"
+ when :request
+ "#{request.protocol}#{host}"
+ else
+ "#{protocol}://#{host}"
+ end
+ end
+ end
+
+ # Computes the path to a javascript asset in the public javascripts directory.
+ # If the +source+ filename has no extension, .js will be appended (except for explicit URIs)
+ # Full paths from the document root will be passed through.
+ # Used internally by javascript_include_tag to build the script path.
+ #
+ # javascript_path "xmlhr" # => /javascripts/xmlhr.js
+ # javascript_path "dir/xmlhr.js" # => /javascripts/dir/xmlhr.js
+ # javascript_path "/dir/xmlhr" # => /dir/xmlhr.js
+ # javascript_path "http://www.example.com/js/xmlhr" # => http://www.example.com/js/xmlhr
+ # javascript_path "http://www.example.com/js/xmlhr.js" # => http://www.example.com/js/xmlhr.js
+ def javascript_path(source, options = {})
+ path_to_asset(source, {type: :javascript}.merge!(options))
+ end
+ alias_method :path_to_javascript, :javascript_path # aliased to avoid conflicts with a javascript_path named route
+
+ # Computes the full URL to a javascript asset in the public javascripts directory.
+ # This will use +javascript_path+ internally, so most of their behaviors will be the same.
+ def javascript_url(source, options = {})
+ url_to_asset(source, {type: :javascript}.merge!(options))
+ end
+ alias_method :url_to_javascript, :javascript_url # aliased to avoid conflicts with a javascript_url named route
+
+ # Computes the path to a stylesheet asset in the public stylesheets directory.
+ # If the +source+ filename has no extension, <tt>.css</tt> will be appended (except for explicit URIs).
+ # Full paths from the document root will be passed through.
+ # Used internally by +stylesheet_link_tag+ to build the stylesheet path.
+ #
+ # stylesheet_path "style" # => /stylesheets/style.css
+ # stylesheet_path "dir/style.css" # => /stylesheets/dir/style.css
+ # stylesheet_path "/dir/style.css" # => /dir/style.css
+ # stylesheet_path "http://www.example.com/css/style" # => http://www.example.com/css/style
+ # stylesheet_path "http://www.example.com/css/style.css" # => http://www.example.com/css/style.css
+ def stylesheet_path(source, options = {})
+ path_to_asset(source, {type: :stylesheet}.merge!(options))
+ end
+ alias_method :path_to_stylesheet, :stylesheet_path # aliased to avoid conflicts with a stylesheet_path named route
+
+ # Computes the full URL to a stylesheet asset in the public stylesheets directory.
+ # This will use +stylesheet_path+ internally, so most of their behaviors will be the same.
+ def stylesheet_url(source, options = {})
+ url_to_asset(source, {type: :stylesheet}.merge!(options))
+ end
+ alias_method :url_to_stylesheet, :stylesheet_url # aliased to avoid conflicts with a stylesheet_url named route
+
+ # Computes the path to an image asset.
+ # Full paths from the document root will be passed through.
+ # Used internally by +image_tag+ to build the image path:
+ #
+ # image_path("edit") # => "/assets/edit"
+ # image_path("edit.png") # => "/assets/edit.png"
+ # image_path("icons/edit.png") # => "/assets/icons/edit.png"
+ # image_path("/icons/edit.png") # => "/icons/edit.png"
+ # image_path("http://www.example.com/img/edit.png") # => "http://www.example.com/img/edit.png"
+ #
+ # If you have images as application resources this method may conflict with their named routes.
+ # The alias +path_to_image+ is provided to avoid that. Rails uses the alias internally, and
+ # plugin authors are encouraged to do so.
+ def image_path(source, options = {})
+ path_to_asset(source, {type: :image}.merge!(options))
+ end
+ alias_method :path_to_image, :image_path # aliased to avoid conflicts with an image_path named route
+
+ # Computes the full URL to an image asset.
+ # This will use +image_path+ internally, so most of their behaviors will be the same.
+ def image_url(source, options = {})
+ url_to_asset(source, {type: :image}.merge!(options))
+ end
+ alias_method :url_to_image, :image_url # aliased to avoid conflicts with an image_url named route
+
+ # Computes the path to a video asset in the public videos directory.
+ # Full paths from the document root will be passed through.
+ # Used internally by +video_tag+ to build the video path.
+ #
+ # video_path("hd") # => /videos/hd
+ # video_path("hd.avi") # => /videos/hd.avi
+ # video_path("trailers/hd.avi") # => /videos/trailers/hd.avi
+ # video_path("/trailers/hd.avi") # => /trailers/hd.avi
+ # video_path("http://www.example.com/vid/hd.avi") # => http://www.example.com/vid/hd.avi
+ def video_path(source, options = {})
+ path_to_asset(source, {type: :video}.merge!(options))
+ end
+ alias_method :path_to_video, :video_path # aliased to avoid conflicts with a video_path named route
+
+ # Computes the full URL to a video asset in the public videos directory.
+ # This will use +video_path+ internally, so most of their behaviors will be the same.
+ def video_url(source, options = {})
+ url_to_asset(source, {type: :video}.merge!(options))
+ end
+ alias_method :url_to_video, :video_url # aliased to avoid conflicts with an video_url named route
+
+ # Computes the path to an audio asset in the public audios directory.
+ # Full paths from the document root will be passed through.
+ # Used internally by +audio_tag+ to build the audio path.
+ #
+ # audio_path("horse") # => /audios/horse
+ # audio_path("horse.wav") # => /audios/horse.wav
+ # audio_path("sounds/horse.wav") # => /audios/sounds/horse.wav
+ # audio_path("/sounds/horse.wav") # => /sounds/horse.wav
+ # audio_path("http://www.example.com/sounds/horse.wav") # => http://www.example.com/sounds/horse.wav
+ def audio_path(source, options = {})
+ path_to_asset(source, {type: :audio}.merge!(options))
+ end
+ alias_method :path_to_audio, :audio_path # aliased to avoid conflicts with an audio_path named route
+
+ # Computes the full URL to an audio asset in the public audios directory.
+ # This will use +audio_path+ internally, so most of their behaviors will be the same.
+ def audio_url(source, options = {})
+ url_to_asset(source, {type: :audio}.merge!(options))
+ end
+ alias_method :url_to_audio, :audio_url # aliased to avoid conflicts with an audio_url named route
+
+ # Computes the path to a font asset.
+ # Full paths from the document root will be passed through.
+ #
+ # font_path("font") # => /assets/font
+ # font_path("font.ttf") # => /assets/font.ttf
+ # font_path("dir/font.ttf") # => /assets/dir/font.ttf
+ # font_path("/dir/font.ttf") # => /dir/font.ttf
+ # font_path("http://www.example.com/dir/font.ttf") # => http://www.example.com/dir/font.ttf
+ def font_path(source, options = {})
+ path_to_asset(source, {type: :font}.merge!(options))
+ end
+ alias_method :path_to_font, :font_path # aliased to avoid conflicts with an font_path named route
+
+ # Computes the full URL to a font asset.
+ # This will use +font_path+ internally, so most of their behaviors will be the same.
+ def font_url(source, options = {})
+ url_to_asset(source, {type: :font}.merge!(options))
+ end
+ alias_method :url_to_font, :font_url # aliased to avoid conflicts with an font_url named route
+ end
+ end
+end