Add #register to ProjectHelper

This feature makes it possible to register that a
file extension should be processed using a
specified filter.

It is implemented by adding a before_filter to all
PipelineDSLs that use the ChainedFilter to
process input files before they are passed to the
rest of the filters.

Gemfile

@@ -3,5 +3,6 @@ source "http://rubygems.org"
 # Specify your gem's dependencies in rake-pipeline-web-filters.gemspec
 gemspec
 
-gem "rake-pipeline", :git => "git://github.com/livingsocial/rake-pipeline.git"
+gem "rake-pipeline", :path => "~/Code/rake-pipeline"
+#gem "rake-pipeline", :git => "git://github.com/livingsocial/rake-pipeline.git"
 gem "pry"

Rakefile

@@ -1,5 +1,6 @@
 #!/usr/bin/env rake
 require "bundler/gem_tasks"
+require "bundler/setup"
 
 desc "run the specs"
 task :spec do

lib/rake-pipeline-web-filters/chained_filter.rb

@@ -47,7 +47,14 @@ def write(contents)
   # a file like +application.js.coffee.erb+ will first
   # apply the +ErbFilter+, then the +CoffeeFilter+, and
   # then output +application.js+.
+  #
+  # This filter is largely designed for use with the
+  # {ProjectHelpers#register register} helper, which
+  # will transparently add a ChainedFilter before each
+  # input block with the registered extensions.
   class ChainedFilter < Rake::Pipeline::Filter
+    attr_reader :filters
+
     # @param [Hash] options
     # @option options [Hash] :types
     #   A hash of file extensions and their associated

lib/rake-pipeline-web-filters/helpers.rb

@@ -13,7 +13,7 @@ module Rake::Pipeline::Web::Filters
   #   match("*.scss") do
   #     sass :syntax => :sass
   #   end
-  module Helpers
+  module PipelineHelpers
     # Add a new {MinispadeFilter} to the pipeline.
     # @see MinispadeFilter#initialize
     def minispade(*args, &block)
@@ -81,6 +81,28 @@ def handlebars(*args, &block)
       filter(Rake::Pipeline::Web::Filters::HandlebarsFilter, *args, &block)
     end
   end
+
+  module ProjectHelpers
+    # Register a filter class for a particular file extension
+    # and add a ChainedFilter as a before filter.
+    #
+    # If this is the first use of +register+, it will set up
+    # the before filter. Subsequent uses will just update the
+    # types hash.
+    #
+    # @see ChainedFilter
+    def register(extension, klass)
+      if @types_hash
+        @types_hash[extension] = klass
+      else
+        @types_hash = { extension => klass }
+        before_filter ChainedFilter, { :types => @types_hash }
+      end
+    end
+  end
 end
 
-Rake::Pipeline::DSL::PipelineDSL.send(:include, Rake::Pipeline::Web::Filters::Helpers)
+require "rake-pipeline/dsl"
+
+Rake::Pipeline::DSL::PipelineDSL.send(:include, Rake::Pipeline::Web::Filters::PipelineHelpers)
+Rake::Pipeline::DSL::ProjectDSL.send(:include, Rake::Pipeline::Web::Filters::ProjectHelpers)

spec/coffee_script_filter_spec.rb

@@ -40,6 +40,10 @@ def output_file(name)
     MemoryFileWrapper.new("/path/to/output", name, "UTF-8")
   end
 
+  def should_match(expected, output)
+    "#{expected}\n".gsub(/\n+/, "\n").should == "#{output}\n".gsub(/\n+/, "\n")
+  end
+
   def setup_filter(filter)
     filter.file_wrapper_class = MemoryFileWrapper
     filter.input_files = [input_file("input.coffee", coffee_input)]
@@ -57,7 +61,7 @@ def setup_filter(filter)
     tasks.each(&:invoke)
 
     file = MemoryFileWrapper.files["/path/to/output/input.js"]
-    file.body.should == expected_coffee_output
+    should_match file.body, expected_coffee_output
     file.encoding.should == "UTF-8"
   end
 
@@ -70,7 +74,7 @@ def setup_filter(filter)
     tasks.each(&:invoke)
 
     file = MemoryFileWrapper.files["/path/to/output/input.js"]
-    file.body.should == expected_unwrapped_coffee_output
+    should_match file.body, expected_unwrapped_coffee_output
     file.encoding.should == "UTF-8"
   end
 
@@ -98,7 +102,7 @@ def setup_filter(filter)
       tasks = filter.generate_rake_tasks
       lambda {
         tasks.each(&:invoke)
-      }.should raise_error(ExecJS::RuntimeError, "Error compiling input.coffee. reserved word \"function\" on line 1")
+      }.should raise_error(ExecJS::RuntimeError, /Error compiling input.coffee. reserved word "function" on line 1/i)
     end
   end
 

spec/helpers_spec.rb

@@ -90,3 +90,35 @@ def filter
     end
   end
 end
+
+describe "ProjectHelpers" do
+  def project
+    @project ||= Rake::Pipeline::Project.new
+  end
+
+  def dsl
+    @dsl ||= Rake::Pipeline::DSL::ProjectDSL.new(project)
+  end
+
+  describe "register" do
+    it "registers filters per file name" do
+      dsl.register :coffee, Rake::Pipeline::Web::Filters::CoffeeScriptFilter
+      dsl.register :handlebars, Rake::Pipeline::Web::Filters::HandlebarsFilter
+
+      dsl.input "lib" do
+        concat "lib.js"
+      end
+
+      dsl.input "tests" do
+        concat "tests.js"
+      end
+
+      project.pipelines.size.should == 2
+
+      project.pipelines.each do |pipeline|
+        pipeline.filters.first.should be_kind_of Rake::Pipeline::Web::Filters::ChainedFilter
+        pipeline.filters.first.filters.keys.should == [:coffee, :handlebars]
+      end
+    end
+  end
+end

spec/spec_helper.rb

@@ -1,6 +1,6 @@
+require "pry"
 require "rake-pipeline"
 require "rake-pipeline-web-filters"
-require "pry"
 
 class Rake::Pipeline
   module SpecHelpers