Allow to remove ansi chars from plain text log

lib/travis/api/app/responders/plain.rb

@@ -16,7 +16,15 @@ module Travis::Api::App::Responders
       headers['Content-Disposition'] = %(#{disposition}; filename="#{filename}")
 
       endpoint.content_type 'text/plain'
-      halt resource.content
+      halt(params[:deansi] ? clear_ansi(resource.content) : resource.content)
     end
+
+    private
+
+      def clear_ansi(content)
+        content.gsub(/\r\r/, "\r")
+               .gsub(/^.*\r(?!$)/, '')
+               .gsub(/\x1b(\[|\(|\))[;?0-9]*[0-9A-Za-z]/m, '')
+      end
   end
 end

spec/unit/endpoint/artifacts_spec.rb

@@ -26,5 +26,19 @@ describe Travis::Api::App::Endpoint::Artifacts do
       response.body.should == artifact.content
       response.headers['Content-Disposition'].should == "attachment; filename=\"#{artifact.id}\""
     end
+
+    describe 'with deansi param' do
+      let(:content) {
+        "Fetching (0%)\rFetching (10%)\rFetching (100%)\n\e[32m"
+      }
+      let(:artifact) { Factory(:log, :content => content) }
+
+      it 'clears ansi escape control characters' do
+        response = get("/artifacts/#{id}.txt", {'deansi' => true})
+
+        response.should be_ok
+        response.body.should == "Fetching (100%)\n"
+      end
+    end
   end
 end