Specify rescue handlers and error formatters using a hash

CHANGELOG.md

@@ -10,6 +10,7 @@ Next Release
 * [#448](https://github.com/intridea/grape/pull/448): Adding POST style parameters for DELETE requests - [@dquimper](https://github.com/dquimper).
 * [#450](https://github.com/intridea/grape/pull/450): Added option to pass an exception handler lambda as an argument to `rescue_from` - [@robertopedroso](https://github.com/robertopedroso).
 * [#443](https://github.com/intridea/grape/pull/443): Let `requires` and `optional` take blocks that initialize new scopes - [@asross](https://github.com/asross).
+* [#452](https://github.com/intridea/grape/pull/452): Added `with` as a hash option to specify handlers for `rescue_from` and `error_formatter` [@robertopedroso](https://github.com/robertopedroso).
 * Your contribution here.
 
 #### Fixes

lib/grape/api.rb

@@ -151,8 +151,14 @@ def default_error_formatter(new_formatter = nil)
         new_formatter ? set(:default_error_formatter, new_formatter) : settings[:default_error_formatter]
       end
 
-      def error_formatter(format, new_formatter)
-        settings.imbue(:error_formatters, format.to_sym => new_formatter)
+      def error_formatter(format, options)
+        if options.is_a?(Hash) && options.has_key?(:with)
+          formatter = options[:with]
+        else
+          formatter = options
+        end
+
+        settings.imbue(:error_formatters, format.to_sym => formatter)
       end
 
       # Specify additional content-types, e.g.:
@@ -197,13 +203,18 @@ def rescue_from(*args, &block)
           handler = block
         end
 
+        options = args.last.is_a?(Hash) ? args.pop : {}
+        if options.has_key?(:with)
+          handler ||= proc { options[:with] }
+        end
+
         if handler
           args.each do |arg|
             imbue(:rescue_handlers, { arg => handler })
           end
         end
 
-        imbue(:rescue_options, args.pop) if args.last.is_a?(Hash)
+        imbue(:rescue_options, options)
         set(:rescue_all, true) and return if args.include?(:all)
         imbue(:rescued_errors, args)
       end

spec/grape/api_spec.rb

@@ -1106,6 +1106,18 @@ class CommunicationError < RuntimeError; end
     end
   end
 
+  describe '.rescue_from klass, with: method' do
+    it 'rescues an error with the specified message' do
+      def rescue_arg_error; Rack::Response.new('rescued with a method', 400); end
+      subject.rescue_from ArgumentError, with: rescue_arg_error
+      subject.get('/rescue_method') { raise ArgumentError }
+
+      get '/rescue_method'
+      last_response.status.should == 400
+      last_response.body.should == 'rescued with a method'
+    end
+  end
+
   describe '.error_format' do
     it 'rescues all errors and return :txt' do
       subject.rescue_from :all
@@ -1171,6 +1183,27 @@ def self.call(message, backtrace, options, env)
       end
     end
 
+    describe 'with' do
+      context 'class' do
+        before :each do
+          class CustomErrorFormatter
+            def self.call(message, backtrace, option, env)
+              "message: #{message} @backtrace"
+            end
+          end
+        end
+
+        it 'returns a custom error format' do
+          subject.rescue_from :all, backtrace: true
+          subject.error_formatter :txt, with: CustomErrorFormatter
+          subject.get('/exception') { raise "rain!" }
+
+          get '/exception'
+          last_response.body.should == 'message: rain! @backtrace'
+        end
+      end
+    end
+
     it 'rescues all errors and return :json' do
       subject.rescue_from :all
       subject.format :json