documentet the renderer and added a spec

lib/zero/renderer.rb

@@ -1,31 +1,90 @@
 module Zero
   class FileNotFoundError < IOError; end
+  # This class helps with rendering of content.
+  #
+  # The purpose of this class is to render templates. All variables pushed into
+  # the renderer should be already processed, so that the raw data can be used.
+  #
+  # The workflow of this class is like the following.
+  #
+  # * setup the type mapping
+  # * create a new instance of the class to prepare rendering
+  # * call #render to process the template
+  #
+  # The call to #render will return the String representation of the template
+  # with all data given.
   class Renderer
-    # set the path to the template base directory
-    def self.template_path(path)
+    # set a base path for template search
+    # @param path [String] the path to the template base dir
+    def self.template_path=(path)
       @@path = path + '/'
     end
 
+    # save a mapping hash for the type
+    #
+    # With that it is possible to map long and complex contant types to simpler
+    # representations. These get then used in the finding process for the best
+    # fitting template.
+    #
+    # @example
+    #   Zero::Renderer.map = {'text/html' => 'html'}
+    #
+    # @param map [Hash] maps the content type to a simple representation
+    def self.type_map=(map)
+      @@map = map
+    end
+
+    # returns the type map
+    # @return [Hash] the mapping for types
+    def self.type_map
+      @@map ||= {}
+    end
+
     # take the path and render the template within the context
+    # @param path [String] the relative path to the template
+    # @param context [Object] the object to process on
+    # @param accept_types
     def initialize(path, context, accept_types)
       accept_types ||= Request::Accept.new('text/html')
       @path    = find_template(path, accept_types)
       @context = context
     end
 
+    # render the template within the context
+    # @return [String] the rendered template
+    def render
+      Tilt.new(@path).render(@context)
+    end
+
+    private
+
     # check if the template does exist
+    # @api private
+    # @param template_path [String] the relative path to the template
+    # @param types [Array] a sorted list of types to search for
+    # @return [String] a file name to use
     def find_template(template_path, types)
       types.each do |type|
-        Dir[@@path + template_path + '.' + type + '.*'].each do |file|
+        Dir[@@path + template_path + '.' + transform(type) + '.*'].each do |file|
           return file
         end
       end
       raise FileNotFoundError.new("Template '#{template_path}' not found!")
     end
 
-    # render the template within the context
-    def render
-      Tilt.new(@path).render(@context)
+    # transform a type into a simpler representation
+    # @api private
+    # @param string [String] the original type name
+    # @return [String] the shorter representation or the original
+    def transform(string)
+      return map[string] if map.has_key?(string)
+      string
+    end
+
+    # an alias to Renderer.map
+    # @api private
+    def map
+      self.class.map
     end
   end
 end

spec/unit/renderer/type_map_spec.rb

@@ -0,0 +1,10 @@
+require 'spec_helper'
+
+describe Zero::Renderer, '.type_map' do
+  subject { Zero::Renderer }
+  let(:mapping) {{ 'test/foo' => 'foo' }}
+  it "saves the map" do
+    subject.type_map = mapping
+    subject.type_map.should be(mapping)
+  end
+end