From 39fc5c9513f69d14dbece70afc347ae7134debc5 Mon Sep 17 00:00:00 2001
From: Jeff Casimir <jeff@casimircreative.com>
Date: Sat, 8 Oct 2011 01:06:19 -0400
Subject: [PATCH] Rewrote technique for getting view_context/helper access

---
 lib/draper.rb                          |  1 +
 lib/draper/base.rb                     |  2 +-
 lib/draper/system.rb                   |  2 +-
 lib/draper/view_context.rb             | 22 +++++++++++++++
 spec/base_spec.rb                      |  5 ++++
 spec/samples/application_controller.rb | 28 +++++++++++++++----
 spec/spec_helper.rb                    |  1 -
 spec/view_context_spec.rb              | 37 ++++++++++++++++++++++++++
 8 files changed, 90 insertions(+), 8 deletions(-)
 create mode 100644 lib/draper/view_context.rb
 create mode 100644 spec/view_context_spec.rb

diff --git a/lib/draper.rb b/lib/draper.rb
index 8e87eab..6320405 100644
--- a/lib/draper.rb
+++ b/lib/draper.rb
@@ -4,5 +4,6 @@ require 'draper/all_helpers'
 require 'draper/base'
 require 'draper/lazy_helpers'
 require 'draper/model_support'
+require 'draper/view_context'
 
 Draper::System.setup
\ No newline at end of file
diff --git a/lib/draper/base.rb b/lib/draper/base.rb
index a79b4a2..054e965 100644
--- a/lib/draper/base.rb
+++ b/lib/draper/base.rb
@@ -101,7 +101,7 @@ module Draper
     #
     # @return [Object] proxy   
     def helpers
-      @helpers ||= ApplicationController::all_helpers
+      @helpers ||= ApplicationController.current_view_context
     end
     alias :h :helpers
 
diff --git a/lib/draper/system.rb b/lib/draper/system.rb
index 6c84611..cbbfe40 100644
--- a/lib/draper/system.rb
+++ b/lib/draper/system.rb
@@ -1,7 +1,7 @@
 module Draper
   class System    
     def self.setup
-      ActionController::Base.send(:extend, Draper::AllHelpers) if defined?(ActionController::Base)
+      ApplicationController.send(:include, Draper::ViewContext) if defined?(ApplicationController)
     end
   end
 end
\ No newline at end of file
diff --git a/lib/draper/view_context.rb b/lib/draper/view_context.rb
new file mode 100644
index 0000000..fb88903
--- /dev/null
+++ b/lib/draper/view_context.rb
@@ -0,0 +1,22 @@
+module Draper
+  module ViewContext
+    module ClassMethods
+      def current_view_context
+        Thread.current[:current_view_context] || 
+          raise("set_current_view_context must be called from a before_filter")
+      end
+    end
+    
+    module InstanceMethods
+      def set_current_view_context
+        Thread.current[:current_view_context] ||= self.class.view_context
+      end
+    end
+    
+    def self.included(source)
+      source.send(:include, InstanceMethods)
+      source.send(:extend, ClassMethods)
+      source.send(:before_filter, :set_current_view_context)
+    end
+  end
+end
\ No newline at end of file
diff --git a/spec/base_spec.rb b/spec/base_spec.rb
index 32840b9..6a16947 100644
--- a/spec/base_spec.rb
+++ b/spec/base_spec.rb
@@ -2,9 +2,14 @@ require 'spec_helper'
 require 'draper'
 
 describe Draper::Base do
+  before(:each){ ApplicationController.new.set_current_view_context }
   subject{ Draper::Base.new(source) }
   let(:source){ Product.new }
 
+  it "should get a valid view_context" do
+    ApplicationController.current_view_context.should be
+  end
+
   context(".lazy_helpers") do
     it "makes Rails helpers available without using the h. proxy" do
       Draper::Base.lazy_helpers
diff --git a/spec/samples/application_controller.rb b/spec/samples/application_controller.rb
index 94d33d3..576991b 100644
--- a/spec/samples/application_controller.rb
+++ b/spec/samples/application_controller.rb
@@ -2,9 +2,27 @@ class ApplicationController
   extend ActionView::Helpers
   extend ActionView::Helpers::TagHelper
   extend ActionView::Helpers::UrlHelper
-  extend ApplicationHelper
-
-  def self.all_helpers
-    self
+  extend ApplicationHelper    
+  
+  def self.view_context
+    @@view_context ||= ApplicationController
   end
-end
\ No newline at end of file
+  
+  def self.view_context=(input)
+    @@view_context = input
+  end
+  
+  def self.hello
+    "Hello!"
+  end
+  
+  @@before_filters = []
+  def self.before_filters
+    @@before_filters
+  end
+  def self.before_filter(name)
+    @@before_filters << name
+  end
+end
+
+Draper::System.setup
\ No newline at end of file
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 6817924..28d7235 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -1,7 +1,6 @@
 require 'rubygems'
 require 'bundler/setup'
 Bundler.require
-require 'draper'
 require './spec/samples/application_helper.rb'
 Dir.glob(['./spec/samples/*.rb', './spec/support/*.rb']) do |file| 
   require file
diff --git a/spec/view_context_spec.rb b/spec/view_context_spec.rb
new file mode 100644
index 0000000..000995f
--- /dev/null
+++ b/spec/view_context_spec.rb
@@ -0,0 +1,37 @@
+require 'spec_helper'
+require 'draper'
+
+describe Draper::ViewContext do
+  let (:app_controller) do
+    ApplicationController
+  end
+  
+  let (:app_controller_instance) do
+    app_controller.new
+  end
+  
+  it "implements .current_view_context" do
+    app_controller.should respond_to(:current_view_context)
+  end
+  
+  it "implements #set_current_view_context" do
+    app_controller_instance.should respond_to(:set_current_view_context)
+  end
+  
+  it "sets and returns the view context" do
+    fake_context = Object.new
+    Thread.current[:current_view_context] = nil
+    app_controller_instance.class.send(:view_context=, fake_context)
+    app_controller_instance.set_current_view_context
+    app_controller.current_view_context.should === fake_context
+  end
+  
+  it "calls #before_filter with #set_current_view_context" do
+    app_controller.before_filters.should include(:set_current_view_context)
+  end
+  
+  it "raises an exception if the view_context is fetched without being set" do
+    Thread.current[:current_view_context] = nil
+    expect {app_controller.current_view_context}.should raise_exception(Exception)
+  end
+end
\ No newline at end of file