Add ability to specify an exclude regex for CDN content

lib/cloudfront_asset_host.rb

@@ -33,6 +33,9 @@ module CloudfrontAssetHost
   # Directories to search for asset files in
   mattr_accessor :asset_dirs
 
+  # Key Regular Expression to filter out/exclude content
+  mattr_accessor :exclude_pattern
+
 
   class << self
 
@@ -45,6 +48,7 @@ def configure
       self.enabled    = false
 
       self.asset_dirs = "images,javascripts,stylesheets"
+      self.exclude_pattern = nil
 
       self.gzip            = true
       self.gzip_extensions = %w(js css)
@@ -58,6 +62,8 @@ def configure
     end
 
     def asset_host(source = nil, request = nil)
+      return '' if source && disable_cdn_for_source?(source)
+
       host = cname.present? ? "http://#{self.cname}" : "http://#{self.bucket_host}"
 
       if source && request && CloudfrontAssetHost.gzip
@@ -98,6 +104,10 @@ def gzip_allowed_for_source?(source)
       CloudfrontAssetHost.gzip_extensions.include?(extension)
     end
 
+    def disable_cdn_for_source?(source)
+      source.match(exclude_pattern) if exclude_pattern.present?
+    end
+
   private
 
     def properly_configured?

lib/cloudfront_asset_host/asset_tag_helper_ext.rb

@@ -10,7 +10,8 @@ def rails_asset_id_with_cloudfront(source)
           asset_id
         else
           path = File.join(ASSETS_DIR, source)
-          asset_id = File.exist?(path) ? CloudfrontAssetHost.key_for_path(path) : ''
+          rewrite_path = File.exist?(path) && !CloudfrontAssetHost.disable_cdn_for_source?(source)
+          asset_id = rewrite_path ? CloudfrontAssetHost.key_for_path(path) : ''
 
           if @@cache_asset_timestamps
             @@asset_timestamps_cache_guard.synchronize do

lib/cloudfront_asset_host/uploader.rb

@@ -42,6 +42,8 @@ def upload_keys_with_paths(keys_paths, options={})
       end
 
       def should_upload?(key, options={})
+        return false if CloudfrontAssetHost.disable_cdn_for_source?(key)
+
         options[:force_write] || !existing_keys.include?(key)
       end
 

test/uploader_test.rb

@@ -125,6 +125,30 @@ class UploaderTest < Test::Unit::TestCase
 
   end
 
+  context 'with exclude_pattern' do
+    setup do
+      @css_md5 = md5_key('stylesheets/style.css')       #7026e6ce3
+      @js_md5 =  md5_key('javascripts/application.js')  #8ed41cb87
+      CloudfrontAssetHost.configure do |config|
+        config.cname  = "assethost.com"
+        config.bucket = "bucketname"
+        config.key_prefix = ""
+        config.s3_config = "#{RAILS_ROOT}/config/s3.yml"
+        config.enabled = false
+        config.exclude_pattern = /style/
+      end
+    end
+
+    should "filter keys out" do
+      bucket_mock = mock
+      bucket_mock.expects(:put).times(3)
+      CloudfrontAssetHost::Uploader.stubs(:bucket).returns(bucket_mock)
+      CloudfrontAssetHost::Uploader.stubs(:existing_keys).returns([])
+
+      CloudfrontAssetHost::Uploader.upload!
+    end
+  end
+
   def md5_key(path)
     CloudfrontAssetHost.send(:md5sum, File.join('test/app/public', path))[0..8]
   end