1 files changed, 86 insertions, 20 deletions

diff --git a/actionpack/lib/action_view/asset_paths.rb b/actionpack/lib/action_view/asset_paths.rb
index 2b1fe545a6..4dd02755d3 100644
--- a/actionpack/lib/action_view/asset_paths.rb
+++ b/actionpack/lib/action_view/asset_paths.rb
@@ -4,7 +4,7 @@ module ActionView
   class AssetPaths #:nodoc:
     attr_reader :config, :controller
 
-    def initialize(config, controller)
+    def initialize(config, controller = nil)
       @config = config
       @controller = controller
     end
@@ -13,21 +13,29 @@ module ActionView
     # Prefix with <tt>/dir/</tt> if lacking a leading +/+. Account for relative URL
     # roots. Rewrite the asset path for cache-busting asset ids. Include
     # asset host, if configured, with the correct request protocol.
-    def compute_public_path(source, dir, ext = nil, include_host = true)
+    #
+    # When include_host is true and the asset host does not specify the protocol
+    # the protocol parameter specifies how the protocol will be added.
+    # When :relative (default), the protocol will be determined by the client using current protocol
+    # When :request, the protocol will be the request protocol
+    # Otherwise, the protocol is used (E.g. :http, :https, etc)
+    def compute_public_path(source, dir, ext = nil, include_host = true, protocol = nil)
       source = source.to_s
       return source if is_uri?(source)
 
       source = rewrite_extension(source, dir, ext) if ext
       source = rewrite_asset_path(source, dir)
-
-      if controller && include_host
-        has_request = controller.respond_to?(:request)
-        source = rewrite_host_and_protocol(source, has_request)
-      end
-
+      source = rewrite_relative_url_root(source, relative_url_root) if has_request?
+      source = rewrite_host_and_protocol(source, protocol) if include_host
       source
     end
 
+    # Return the filesystem path for the source
+    def compute_source_path(source, dir, ext)
+      source = rewrite_extension(source, dir, ext) if ext
+      File.join(config.assets_dir, dir, source)
+    end
+
     def is_uri?(path)
       path =~ %r{^[-a-z]+://|^cid:|^//}
     end
@@ -46,13 +54,45 @@ module ActionView
       relative_url_root && !source.starts_with?("#{relative_url_root}/") ? "#{relative_url_root}#{source}" : source
     end
 
-    def rewrite_host_and_protocol(source, has_request)
-      source = rewrite_relative_url_root(source, controller.config.relative_url_root) if has_request
+    def has_request?
+      controller.respond_to?(:request)
+    end
+
+    def rewrite_host_and_protocol(source, protocol = nil)
       host = compute_asset_host(source)
-      if has_request && host && !is_uri?(host)
-        host = "#{controller.request.protocol}#{host}"
+      if host && !is_uri?(host)
+        if (protocol || default_protocol) == :request && !has_request?
+          host = nil
+        else
+          host = "#{compute_protocol(protocol)}#{host}"
+        end
+      end
+      host.nil? ? source : "#{host}#{source}"
+    end
+
+    def compute_protocol(protocol)
+      protocol ||= default_protocol
+      case protocol
+      when :relative
+        "//"
+      when :request
+        unless @controller
+          invalid_asset_host!("The protocol requested was :request. Consider using :relative instead.")
+        end
+        @controller.request.protocol
+      else
+        "#{protocol}://"
       end
-      "#{host}#{source}"
+    end
+
+    def default_protocol
+      protocol = @config.action_controller.default_asset_host_protocol if @config.action_controller.present?
+      protocol ||= @config.default_asset_host_protocol
+      protocol || (has_request? ? :request : :relative)
+    end
+
+    def invalid_asset_host!(help_message)
+      raise ActionController::RoutingError, "This asset host cannot be computed without a request in scope. #{help_message}"
     end
 
     # Pick an asset host for this source. Returns +nil+ if no host is set,
@@ -61,19 +101,45 @@ module ActionView
     # or the value returned from invoking call on an object responding to call
     # (proc or otherwise).
     def compute_asset_host(source)
-      if host = config.asset_host
+      if host = asset_host_config
         if host.respond_to?(:call)
-          case host.is_a?(Proc) ? host.arity : host.method(:call).arity
-          when 2
-            request = controller.respond_to?(:request) && controller.request
-            host.call(source, request)
-          else
-            host.call(source)
+          args = [source]
+          arity = arity_of(host)
+          if arity > 1 && !has_request?
+            invalid_asset_host!("Remove the second argument to your asset_host Proc if you do not need the request.")
           end
+          args << current_request if (arity > 1 || arity < 0) && has_request?
+          host.call(*args)
         else
           (host =~ /%d/) ? host % (source.hash % 4) : host
         end
       end
     end
+
+    def relative_url_root
+      config = controller.config if controller.respond_to?(:config)
+      config ||= config.action_controller if config.action_controller.present?
+      config ||= config
+      config.relative_url_root
+    end
+
+    def asset_host_config
+      if config.action_controller.present?
+        config.action_controller.asset_host
+      else
+        config.asset_host
+      end
+    end
+
+    # Returns the current request if one exists.
+    def current_request
+      controller.request if has_request?
+    end
+
+    # Returns the arity of a callable
+    def arity_of(callable)
+      callable.respond_to?(:arity) ? callable.arity : callable.method(:call).arity
+    end
+
   end
 end