added support gzip content encoding

lib/oauth2/response.rb

@@ -43,7 +43,7 @@ def status
 
     # The HTTP response body
     def body
-      response.body || ''
+      @body ||= preprocessing_of_body(response.body)
     end
 
     # Procs that, when called, will parse a response body according
@@ -82,6 +82,19 @@ def parser
       return options[:parse].to_sym if PARSERS.key?(options[:parse])
       CONTENT_TYPES[content_type]
     end
+
+    private
+
+    def content_encoding
+      ((response.headers.values_at('content-encoding', 'Content-Encoding').compact.first || '').split(';').first || '').strip
+    end
+
+    def preprocessing_of_body(resp_body)
+      return '' if resp_body.nil? || resp_body.empty?
+
+      content_encoding == 'gzip' ? Zlib::GzipReader.new(StringIO.new(resp_body)).read : resp_body
+    end
+
   end
 end
 

spec/oauth2/response_spec.rb

@@ -1,4 +1,5 @@
 require 'helper'
+require 'zlib'
 
 describe OAuth2::Response do
   describe '#initialize' do
@@ -88,4 +89,19 @@
       OAuth2::Response.new(response).parsed.should == {"foo" => {"bar" => "baz"}}
     end
   end
+
+  describe 'when gzip content-encoding' do
+    let(:headers) {{ 'content-type' => 'application/json', 'content-encoding' => 'gzip' }}
+    let(:original_data) {{ 'data' => 'some test data' }}
+    let(:body) do
+      str_io = StringIO.new("w")
+      Zlib::GzipWriter.new(str_io).tap do |gz|
+        gz.write(MultiJson.dump(original_data))
+        gz.close
+      end
+      compressed = str_io.string
+    end
+    let(:response) { double('response', status: 200, headers: headers, body: body) }
+    specify { OAuth2::Response.new(response).parsed.should eq original_data }
+  end
 end