Allow custom formatters.

Author: spraints

lib/grape/middleware/formatter.rb

@@ -11,17 +11,26 @@ class Formatter < Base
         :rss => 'application/rss+xml',
         :txt => 'text/plain'
       }
+      FORMATTERS = {
+        :json => :encode_json,
+        :txt => :encode_txt,
+      }
 
       def default_options
         { 
           :default_format => :txt,
+          :formatters => {},
           :content_types => {}
         }
       end
 
       def content_types
         CONTENT_TYPES.merge(options[:content_types])
       end
+
+      def formatters
+        FORMATTERS.merge(options[:formatters])
+      end
 
       def mime_types
         content_types.invert
@@ -75,18 +84,25 @@ def mime_array
 
       def after
         status, headers, bodies = *@app_response
-        bodymap = []
-        bodies.each do |body|
-          bodymap << case env['api.format']
-            when :json
-              encode_json(body)
-            when :txt
-              encode_txt(body)
-          end
+        formatter = formatter_for env['api.format']
+        bodymap = bodies.collect do |body|
+          formatter.call(body)
         end
         headers['Content-Type'] = content_types[env['api.format']]
         Rack::Response.new(bodymap, status, headers).to_a
       end
+
+      def formatter_for(api_format)
+        spec = formatters[api_format]
+        case spec
+        when nil
+          lambda { |obj| obj }
+        when Symbol
+          method(spec)
+        else
+          spec
+        end
+      end
 
       def encode_json(object)
         if object.respond_to? :serializable_hash

spec/grape/middleware/formatter_spec.rb

@@ -104,4 +104,23 @@ def serializable_hash
       headers['Content-type'].should == 'application/x-custom'
     end
   end
+
+  context 'Format' do
+    it 'should use custom formatter' do
+      subject.options[:content_types][:custom] = "don't care"
+      subject.options[:formatters][:custom] = lambda { |obj| 'CUSTOM FORMAT' }
+      _, _, body = subject.call({'PATH_INFO' => '/info.custom'})
+      body.body.should == ['CUSTOM FORMAT']
+    end
+    it 'should use default json formatter' do
+      @body = 'blah'
+      _, _, body = subject.call({'PATH_INFO' => '/info.json'})
+      body.body.should == ['"blah"']
+    end
+    it 'should use custom json formatter' do
+      subject.options[:formatters][:json] = lambda { |obj| 'CUSTOM JSON FORMAT' }
+      _, _, body = subject.call({'PATH_INFO' => '/info.json'})
+      body.body.should == ['CUSTOM JSON FORMAT']
+    end
+  end
 end