Added rescue_with_backtrace true/false.

Author: dblock

README.markdown

@@ -66,10 +66,11 @@ Serialization takes place automatically. For more detailed usage information, pl
 
 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. 
 
-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`.
+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`.
 
     class Twitter::API < Grape::API
       rescue_all_errors true
+      rescue_with_backtrace true
       error_format :json
       default_error_status 200
 

lib/grape/api.rb

@@ -95,6 +95,11 @@ def rescue_all_errors(new_value = true)
         set(:rescue_all_errors, new_value)
       end
 
+      # Specify whether to include error backtrace with errors.
+      def rescue_with_backtrace(new_value = true)
+        set(:rescue_with_backtrace, new_value)
+      end
+
       # Add helper methods that will be accessible from any
       # endpoint within this namespace (and child namespaces).
       #
@@ -233,7 +238,7 @@ def nest(*blocks, &block)
 
       def build_endpoint(&block)
         b = Rack::Builder.new
-        b.use Grape::Middleware::Error, :default_status => settings[:default_error_status] || 403, :rescue => settings[:rescue_all_errors], :format => settings[:error_format] || :txt
+        b.use Grape::Middleware::Error, :default_status => settings[:default_error_status] || 403, :rescue => settings[:rescue_all_errors], :format => settings[:error_format] || :txt, :backtrace => settings[:rescue_with_backtrace]
         b.use Rack::Auth::Basic, settings[:auth][:realm], &settings[:auth][:proc] if settings[:auth] && settings[:auth][:type] == :http_basic
         b.use Grape::Middleware::Prefixer, :prefix => prefix if prefix        
         b.use Grape::Middleware::Versioner, :versions => (version if version.is_a?(Array)) if version

lib/grape/middleware/error.rb

@@ -11,6 +11,7 @@ def default_options
         :default_message => "",
         :format => :txt,
         :formatters => {},
+        :backtrace => false, # true to display backtrace
       }
       end
 
@@ -35,12 +36,21 @@ def formatter_for(api_format)
         end
       end
 
-      def format_json(message)
-        { :error => message }.to_json
+      def format_json(message, backtrace)
+        result = { :error => message }
+        if (options[:backtrace] && backtrace && ! backtrace.empty?)
+          result = result.merge({ :backtrace => backtrace })
+        end
+        result.to_json
       end
 
-      def format_txt(message)
-        message
+      def format_txt(message, backtrace)
+        result = message
+        if options[:backtrace] && backtrace && ! backtrace.empty?
+          result += "\r\n "
+          result += backtrace.join("\r\n ")
+        end
+        result
       end
 
       def call!(env)
@@ -52,7 +62,7 @@ def call!(env)
           })
         rescue Exception => e
           raise unless options[:rescue]
-          error_response({ :message => e.message })
+          error_response({ :message => e.message, :backtrace => e.backtrace })
         end
 
       end
@@ -61,13 +71,14 @@ def error_response(error = {})
         status = error[:status] || options[:default_status]
         message = error[:message] || options[:default_message]
         headers = error[:headers] || {}
-        Rack::Response.new([format_message(message, status)], status, headers).finish
+        backtrace = error[:backtrace] || []
+        Rack::Response.new([format_message(message, backtrace, status)], status, headers).finish
       end
 
-      def format_message(message, status)
+      def format_message(message, backtrace, status)
         formatter = formatter_for(options[:format])
         throw :error, :status => 406, :message => "The requested format #{options[:format]} is not supported." unless formatter        
-        formatter.call(message)
+        formatter.call(message, backtrace)
       end
 
     end

spec/grape/api_spec.rb

@@ -491,7 +491,7 @@ def two
   end
 
   describe ".error_format" do
-    it 'should return :txt' do
+    it 'should rescue all errors and return :txt' do
       subject.rescue_all_errors true
       subject.error_format :txt
       subject.get '/exception' do
@@ -500,7 +500,17 @@ def two
       get '/exception'
       last_response.body.should eql "rain!"
     end
-    it 'should rescue all errors' do
+    it 'should rescue all errros and return :txt with backtrace' do
+      subject.rescue_all_errors true
+      subject.error_format :txt
+      subject.rescue_with_backtrace true
+      subject.get '/exception' do
+        raise "rain!"
+      end    
+      get '/exception'
+      last_response.body.start_with?("rain!\r\n").should be_true
+    end
+    it 'should rescue all errors and return :json' do
       subject.rescue_all_errors true
       subject.error_format :json
       subject.get '/exception' do
@@ -509,15 +519,27 @@ def two
       get '/exception'
       last_response.body.should eql '{"error":"rain!"}'
     end
-    it 'should rescue all errors' do
+    it 'should rescue all errors and return :json with backtrace' do
+      subject.rescue_all_errors true
+      subject.error_format :json
+      subject.rescue_with_backtrace true
+      subject.get '/exception' do
+        raise "rain!"
+      end    
+      get '/exception'
+      json = JSON.parse(last_response.body)
+      json["error"].should eql 'rain!'
+      json["backtrace"].length.should > 0
+    end
+    it 'should rescue error! and return txt' do
       subject.error_format :txt
       subject.get '/error' do
         error!("Access Denied", 401)
       end    
       get '/error'
       last_response.body.should eql "Access Denied"
     end
-    it 'should rescue all errors' do
+    it 'should rescue error! and return json' do
       subject.error_format :json
       subject.get '/error' do
         error!("Access Denied", 401)

spec/grape/middleware/exception_spec.rb

@@ -73,7 +73,7 @@ def app
       use Grape::Middleware::Error, 
         :format => :custom, 
         :formatters => { 
-          :custom => lambda { |message| { :custom_formatter => message } }  
+          :custom => lambda { |message, backtrace| { :custom_formatter => message } }  
         }
       run ExceptionApp
     end