Add asset_url helper and refactor the asset paths so that asset hosts can be used during asset precompilation.

Conflicts:

	actionpack/lib/action_view/asset_paths.rb
	actionpack/lib/sprockets/helpers/rails_helper.rb
	actionpack/test/template/sprockets_helper_test.rb

3 files changed, 75 insertions, 39 deletions

diff --git a/actionpack/lib/action_view/asset_paths.rb b/actionpack/lib/action_view/asset_paths.rb
index 2b1fe545a6..4974bd5426 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
@@ -19,15 +19,17 @@ module ActionView
 
       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) 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 +48,14 @@ 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)
       host = compute_asset_host(source)
-      if has_request && host && !is_uri?(host)
-        host = "#{controller.request.protocol}#{host}"
-      end
-      "#{host}#{source}"
+      host = "//#{host}" if host && !is_uri?(host)
+      host.nil? ? source : "#{host}#{source}"
     end
 
     # Pick an asset host for this source. Returns +nil+ if no host is set,
@@ -61,19 +64,48 @@ 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?
+            raise ActionController::RoutingError, "This asset host cannot be computed without a request in scope. 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
+      if controller.respond_to?(:config) && controller.config
+        controller.config.relative_url_root
+      elsif config.respond_to?(:action_controller) && config.action_controller
+        config.action_controller.relative_url_root
+      elsif Rails.respond_to?(:application) && Rails.application.config
+        Rails.application.config.action_controller.relative_url_root
+      end
+    end
+
+    def asset_host_config
+      if config.respond_to?(:asset_host)
+        config.asset_host
+      elsif Rails.respond_to?(:application)
+        Rails.application.config.action_controller.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
diff --git a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
index e4662a2919..16d8f3f893 100644
--- a/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
+++ b/actionpack/lib/action_view/helpers/asset_tag_helpers/asset_include_tag.rb
@@ -60,12 +60,16 @@ module ActionView
 
         private
 
-          def path_to_asset(source, include_host = true)
-            asset_paths.compute_public_path(source, asset_name.to_s.pluralize, extension, include_host)
+          def path_to_asset(source)
+            asset_paths.compute_public_path(source, asset_name.to_s.pluralize, extension)
+          end
+
+          def path_to_asset_source(source)
+            asset_paths.compute_source_path(source, asset_name.to_s.pluralize, extension)
           end
 
           def compute_paths(*args)
-            expand_sources(*args).collect { |source| asset_paths.compute_public_path(source, asset_name.pluralize, extension, false) }
+            expand_sources(*args).collect { |source| path_to_asset_source(source) }
           end
 
           def expand_sources(sources, recursive)
@@ -92,7 +96,7 @@ module ActionView
 
           def ensure_sources!(sources)
             sources.each do |source|
-              asset_file_path!(path_to_asset(source, false))
+              asset_file_path!(path_to_asset_source(source))
             end
           end
 
@@ -123,19 +127,14 @@ module ActionView
 
             # Set mtime to the latest of the combined files to allow for
             # consistent ETag without a shared filesystem.
-            mt = asset_paths.map { |p| File.mtime(asset_file_path(p)) }.max
+            mt = asset_paths.map { |p| File.mtime(asset_file_path!(p)) }.max
             File.utime(mt, mt, joined_asset_path)
           end
 
-          def asset_file_path(path)
-            File.join(config.assets_dir, path.split('?').first)
-          end
-
-          def asset_file_path!(path, error_if_file_is_uri = false)
-            if asset_paths.is_uri?(path)
+          def asset_file_path!(absolute_path, error_if_file_is_uri = false)
+            if asset_paths.is_uri?(absolute_path)
               raise(Errno::ENOENT, "Asset file #{path} is uri and cannot be merged into single file") if error_if_file_is_uri
             else
-              absolute_path = asset_file_path(path)
               raise(Errno::ENOENT, "Asset file not found at '#{absolute_path}'" ) unless File.exist?(absolute_path)
               return absolute_path
             end
diff --git a/actionpack/lib/sprockets/helpers/rails_helper.rb b/actionpack/lib/sprockets/helpers/rails_helper.rb
index 9f1f0f3b68..ef7cf9e051 100644
--- a/actionpack/lib/sprockets/helpers/rails_helper.rb
+++ b/actionpack/lib/sprockets/helpers/rails_helper.rb
@@ -58,23 +58,28 @@ module Sprockets
         end.join("\n").html_safe
       end
 
+      def asset_path(source, default_ext = nil, body = false)
+        source = source.logical_path if source.respond_to?(:logical_path)
+        path = asset_paths.compute_public_path(source, 'assets', default_ext)
+        body ? "#{path}?body=1" : path
+      end
+
     private
       def debug_assets?
         params[:debug_assets] == '1' ||
           params[:debug_assets] == 'true'
       end
 
-      def asset_path(source, default_ext = nil, body = false)
-        source = source.logical_path if source.respond_to?(:logical_path)
-        path = asset_paths.compute_public_path(source, Rails.application.config.assets.prefix, default_ext, true)
-        body ? "#{path}?body=1" : path
-      end
-
       class AssetPaths < ::ActionView::AssetPaths #:nodoc:
         def compute_public_path(source, dir, ext=nil, include_host=true)
           super(source, Rails.application.config.assets.prefix, ext, include_host)
         end
 
+        # Return the filesystem path for the source
+        def compute_source_path(source, ext)
+          asset_for(source, ext)
+        end
+
         def asset_for(source, ext)
           source = source.to_s
           return nil if is_uri?(source)
@@ -104,7 +109,7 @@ module Sprockets
 
         # When included in Sprockets::Context, we need to ask the top-level config as the controller is not available
         def performing_caching?
-          @config ?  @config.perform_caching : Rails.application.config.action_controller.perform_caching
+          @config ? @config.perform_caching : Rails.application.config.action_controller.perform_caching
         end
       end
     end