Merge pull request ruby-grape#66 from dblock/rescue-from

fixed rescue_from, broken when trying to rescue multiple specific exceptions

Author: Michael Bleigh

README.markdown

@@ -8,7 +8,7 @@ Grape is a REST-like API micro-framework for Ruby. It is built to complement exi
 Grape is available as a gem, to install it just install the gem:
 
     gem install grape
-    
+
 ## Basic Usage
 
 Grape APIs are Rack applications that are created by subclassing `Grape::API`. Below is a simple example showing some of the more common features of Grape in the context of recreating parts of the Twitter API.
@@ -57,20 +57,20 @@ Grape APIs are Rack applications that are created by subclassing `Grape::API`. B
         end
       end
     end
-    
+
 This would create a Rack application that could be used like so (in a Rackup config.ru file):
 
     run Twitter::API
-    
+
 And would respond to the following routes:
 
     GET  /1/statuses/public_timeline(.json)
     GET  /1/statuses/home_timeline(.json)
     GET  /1/statuses/show/:id(.json)
     POST /1/statuses/update(.json)
-    
+
 Serialization takes place automatically. For more detailed usage information, please visit the [Grape Wiki](http://github.com/intridea/grape/wiki).
-    
+
 ## Raising Errors
 
 You can raise errors explicitly.
@@ -117,6 +117,15 @@ You can also rescue specific exceptions with a code block and handle the Rack re
       end
     end
 
+    class Twitter::API < Grape::API
+      rescue_from ArgumentError do |e|
+        Rack::Response.new([ "ArgumentError: #{e.message}" ], 500)
+      end
+      rescue_from NotImplementedError do |e|
+        Rack::Response.new([ "NotImplementedError: #{e.message}" ], 500)
+      end
+    end
+
 ## Writing Tests
 
 You can test a Grape API with RSpec. Tests make HTTP requests, therefore they must go into the `spec/request` group. You may want your API code to go into `app/api` - you can match that layout under `spec` by adding the following in `spec/spec_helper.rb`.

lib/grape/api.rb

@@ -52,6 +52,22 @@ def set(key, value)
         @settings.last[key.to_sym] = value
       end
 
+      # Add to a configuration value for this
+      # namespace.
+      #
+      # @param key [Symbol] The key of the configuration variable.
+      # @param value [Object] The value to which to set the configuration variable.
+      def add(key, value)
+        current = @settings.last[key.to_sym]
+        if current.is_a?(Array)
+          current.concat(value)
+        elsif current.is_a?(Hash)
+          current.merge!(value)
+        else
+          @settings.last[key.to_sym] = value
+        end
+      end
+      
       # Define a root URL prefix for your entire
       # API.
       def prefix(prefix = nil)
@@ -122,12 +138,12 @@ def default_error_status(new_status = nil)
       def rescue_from(*args, &block)
         if block_given?
           args.each do |arg|
-            set(:rescue_handlers, { arg => block })
+            add(:rescue_handlers, { arg => block })
           end
         end
-        set(:rescue_options, args.pop) if args.last.is_a?(Hash)
+        add(:rescue_options, args.pop) if args.last.is_a?(Hash)
         set(:rescue_all, true) and return if args.include?(:all)
-        set(:rescued_errors, args)
+        add(:rescued_errors, args)
       end
 
       # Add helper methods that will be accessible from any

spec/grape/api_spec.rb

@@ -743,6 +743,28 @@ class ConnectionError < RuntimeError; end
       last_response.status.should eql 500
       last_response.body.should == 'rescued from ConnectionError'
     end
+    it 'should rescue multiple specific errors' do
+      class ConnectionError < RuntimeError; end
+      class DatabaseError < RuntimeError; end
+      subject.rescue_from ConnectionError do |e|
+        rack_response("rescued from #{e.class.name}", 500)
+      end
+      subject.rescue_from DatabaseError do |e|
+        rack_response("rescued from #{e.class.name}", 500)
+      end
+      subject.get '/connection' do
+        raise ConnectionError
+      end
+      subject.get '/database' do
+        raise DatabaseError
+      end
+      get '/connection'
+      last_response.status.should eql 500
+      last_response.body.should == 'rescued from ConnectionError'
+      get '/database'
+      last_response.status.should eql 500
+      last_response.body.should == 'rescued from DatabaseError'
+    end
     it 'should not rescue a different error' do
       class CommunicationError < RuntimeError; end
       subject.rescue_from RuntimeError do |e|