Supporting hash objects in error.

Author: dblock

README.markdown

@@ -62,11 +62,19 @@ And would respond to the following routes:
 
 Serialization takes place automatically. For more detailed usage information, please visit the [Grape Wiki](http://github.com/intridea/grape/wiki).
 
-## Error Handling
+## Raising Errors
 
-The default behavior of Grape is to rescue all exceptions and to return a 403 status code with the exception's message in the response body. 
+You can raise errors explicitly.
 
-It's possible to trap all exceptions by setting `rescue_all_errors true`. This prevents displaying the web server's error page as a result. You may also change the error format to JSON by using `error_format :json` and set the default error status to 200 with `default_error_status 200`. You may also include the complete backtrace of the exception with `rescue_with_backtrace true`.
+    error!("Access Denied", 401)
+
+You can also return JSON formatted objects explicitly by raising error! and passing a hash instead of a message.
+
+    error!({ "error" => "unexpected error", "detail" => "missing widget" }, 500)
+
+## Exception Handling
+
+By default Grape does not catch all unexpected exceptions. This means that the web server will handle the error and render the default error page as a result. It is possible to trap all exceptions by setting `rescue_all_errors true` instead. You may change the error format to JSON by using `error_format :json` and set the default error status to 200 with `default_error_status 200`. You may also include the complete backtrace of the exception with `rescue_with_backtrace true` either as text (for the :txt format) or as a :backtrace field in the json (for the :json format).
 
     class Twitter::API < Grape::API
       rescue_all_errors true

lib/grape/middleware/error.rb

@@ -37,15 +37,15 @@ def formatter_for(api_format)
       end
 
       def format_json(message, backtrace)
-        result = { :error => message }
+        result = message.is_a?(Hash) ? message : { :error => message }
         if (options[:backtrace] && backtrace && ! backtrace.empty?)
           result = result.merge({ :backtrace => backtrace })
         end
         result.to_json
       end
 
       def format_txt(message, backtrace)
-        result = message
+        result = message.is_a?(Hash) ? message.to_json : message
         if options[:backtrace] && backtrace && ! backtrace.empty?
           result += "\r\n "
           result += backtrace.join("\r\n ")

spec/grape/endpoint_spec.rb

@@ -73,8 +73,6 @@ def app; subject end
     end
 
     it 'should accept an object and render it in format' do
-      pending
-
       subject.get '/hey' do
         error!({'dude' => 'rad'}, 403)
       end

spec/grape/middleware/exception_spec.rb

@@ -1,14 +1,29 @@
 require 'spec_helper'
 
 describe Grape::Middleware::Error do
+  
+  # raises a text exception
   class ExceptionApp
     class << self
       def call(env)
         raise "rain!"
       end
     end
   end
-
+  
+  # raises a hash error
+  class ErrorHashApp
+    class << self
+      def error!(message, status=403)
+        throw :error, :message => { :error => message, :detail => "missing widget" }, :status => status
+      end
+      def call(env)
+        error!("rain!", 401)
+      end
+    end
+  end
+  
+  # raises an error!
   class AccessDeniedApp    
     class << self
       def error!(message, status=403)
@@ -68,6 +83,15 @@ def app
     last_response.body.should == '{"error":"rain!"}'
   end
 
+  it 'should be possible to return hash errors in json format' do
+    @app ||= Rack::Builder.app do
+      use Grape::Middleware::Error, :format => :json
+      run ErrorHashApp
+    end
+    get '/'
+    last_response.body.should == '{"error":"rain!","detail":"missing widget"}'
+  end
+
   it 'should be possible to specify a custom formatter' do
     @app ||= Rack::Builder.app do
       use Grape::Middleware::Error,