WIP - Rendering pipeline.

middleman-core/lib/middleman-core/extensions/pipeline.rb

@@ -0,0 +1,19 @@
+class Middleman::Extensions::Pipeline < Middleman::Extension
+  expose_to_config :pipeline
+
+  def initialize(app, options_hash={}, &block)
+    super
+    @pipelines = []
+  end
+
+  def pipeline(&block)
+    @pipelines << block
+  end
+
+  def manipulate_resource_list(resources)
+    @pipelines.each do |pipeline|
+      pipeline.call resources
+    end
+    resources
+  end
+end

middleman-core/lib/middleman-core/pipeline.rb

@@ -0,0 +1,24 @@
+require 'forwardable'
+
+module Middleman
+  class Pipeline
+    extend Forwardable
+    attr_reader :filters
+    attr_reader :resource
+
+    def_delegators :filters, :<<, :push, :unshift, :insert, :shift, :pop, :first, :clear
+
+    def initialize(resource)
+      @resource = resource
+      @filters = []
+    end
+
+    def render(*args)
+      process resource.render *args
+    end
+
+    def process(body)
+      filters.inject(body){ |body, app| app.call(body) }
+    end
+  end
+end

middleman-core/lib/middleman-core/rack.rb

@@ -109,7 +109,7 @@ module Middleman
 
       begin
         # Write out the contents of the page
-        res.write resource.render({}, rack: { request: req })
+        res.write resource.pipeline.render({}, rack: { request: req })
 
         # Valid content is a 200 status
         res.status = 200

middleman-core/lib/middleman-core/sitemap/resource.rb

@@ -3,6 +3,7 @@ require 'middleman-core/sitemap/extensions/traversal'
 require 'middleman-core/file_renderer'
 require 'middleman-core/template_renderer'
 require 'middleman-core/contracts'
+require 'middleman-core/pipeline'
 
 module Middleman
   # Sitemap namespace
@@ -40,6 +41,8 @@ module Middleman
 
       attr_accessor :ignored
 
+      attr_reader :pipeline
+
       # Initialize resource with parent store and URL
       # @param [Middleman::Sitemap::Store] store
       # @param [String] path
@@ -50,6 +53,7 @@ module Middleman
         @app         = @store.app
         @path        = path
         @ignored     = false
+        @pipeline    = Pipeline.new(self)
 
         source = Pathname(source) if source && source.is_a?(String)