Add error! to rescue_from. Fixes ruby-grape#889.

CHANGELOG.md

@@ -13,6 +13,7 @@
 * [#952](https://github.com/intridea/grape/pull/952): Status method now raises error when called with invalid status code - [@dabrorius](https://github.com/dabrorius).
 * [#957](https://github.com/intridea/grape/pull/957): Regexp validator now supports `allow_blank`, `nil` value behavior changed - [@calfzhou](https://giihub.com/calfzhou).
 * [#962](https://github.com/intridea/grape/pull/962): The `default` attribute with `false` value is documented now - [@ajvondrak](https://github.com/ajvondrak).
+* [#974](https://github.com/intridea/grape/pull/974): Add error! to rescue_from blocks - [@whatasunnyday](https://github.com/whatasunnyday).
 * Your contribution here.
 
 0.11.0 (2/23/2015)

README.md

@@ -1031,7 +1031,7 @@ You can rescue a `Grape::Exceptions::ValidationErrors` and respond with a custom
 ```ruby
 format :json
 subject.rescue_from Grape::Exceptions::ValidationErrors do |e|
-  rack_response e.to_json, 400
+  error! e, 400
 end
 ```
 
@@ -1442,17 +1442,29 @@ class Twitter::API < Grape::API
 end
 ```
 
-You can rescue all exceptions with a code block. The `error_response` wrapper
+You can rescue all exceptions with a code block. The `error!` wrapper
 automatically sets the default error code and content-type.
 
 ```ruby
 class Twitter::API < Grape::API
   rescue_from :all do |e|
-    error_response({ message: "rescued from #{e.class.name}" })
+    error!("rescued from #{e.class.name}")
   end
 end
 ```
 
+Optionally, you can set the format, status code and headers.
+
+```ruby
+class Twitter::API < Grape::API
+  format :json
+  rescue_from :all do |e|
+    error!({ error: "Server error.", 500, { 'Content-Type' => 'text/error' } })
+  end
+end
+```
+
+
 You can also rescue specific exceptions with a code block and handle the Rack
 response at the lowest level.
 
@@ -1469,10 +1481,11 @@ Or rescue specific exceptions.
 ```ruby
 class Twitter::API < Grape::API
   rescue_from ArgumentError do |e|
-    Rack::Response.new([ "ArgumentError: #{e.message}" ], 500).finish
+    error!("ArgumentError: #{e.message}")
   end
+
   rescue_from NotImplementedError do |e|
-    Rack::Response.new([ "NotImplementedError: #{e.message}" ], 500).finish
+    error!("NotImplementedError: #{e.message}")
   end
 end
 ```
@@ -1492,10 +1505,10 @@ Then the following `rescue_from` clause will rescue exceptions of type `APIError
 
 ```ruby
 rescue_from APIErrors::ParentError do |e|
-    Rack::Response.new({
+    error!({
       error: "#{e.class} error",
       message: e.message
-      }.to_json, e.status).finish
+    }, e.status)
 end
 ```
 
@@ -1504,11 +1517,11 @@ The code below will rescue exceptions of type `RuntimeError` but _not_ its subcl
 
 ```ruby
 rescue_from RuntimeError, rescue_subclasses: false do |e|
-    Rack::Response.new({
+    error!({
       status: e.status,
       message: e.message,
       errors: e.errors
-      }.to_json, e.status).finish
+    }, e.status)
 end
 ```
 

UPGRADING.md

@@ -15,6 +15,45 @@ end
 
 See [#957](https://github.com/intridea/grape/pull/957) for more information.
 
+#### Optionally replace error_response with error! in rescue_from blocks
+
+```ruby
+def error!(message, status = options[:default_status], headers = {}, backtrace = [])
+  headers = { 'Content-Type' => content_type }.merge(headers)
+  rack_response(format_message(message, backtrace), status, headers)
+end
+```
+
+For example,
+
+```
+error_response({ message: { message: 'No such page.', id: 'missing_page' }, status: 404, headers: { 'Content-Type' => 'api/error' })
+```
+
+becomes
+
+```
+error!({ message: 'No such page.', id: 'missing_page' }, 404, { 'Content-Type' => 'api/error' })
+```
+
+`error!` also supports just passing a message. `error!('Server error.')` and `format: :json` returns the following JSON response
+
+```
+{ 'error': 'Server error. }
+```
+
+with a status code of 500 and a Content Type of text/error.
+
+Optionally, also replace `Rack::Response.new` with `error!.`
+The following are equivalent:
+
+```
+Rack::Response.new([ e.message ], 500, { "Content-type" => "text/error" }).finish
+error!(e)
+```
+
+See [#889](https://github.com/intridea/grape/issues/889) for more information.
+
 ### Upgrading to >= 0.11.0
 
 #### Added Rack 1.6.0 support

lib/grape/error_formatter/json.rb

@@ -5,7 +5,7 @@ class << self
         def call(message, backtrace, options = {}, env = nil)
           message = Grape::ErrorFormatter::Base.present(message, env)
 
-          result = message.is_a?(Hash) ? message : { error: message }
+          result = message.is_a?(String) ?  { error: message } : message
           if (options[:rescue_options] || {})[:backtrace] && backtrace && !backtrace.empty?
             result = result.merge(backtrace: backtrace)
           end

lib/grape/exceptions/validation_errors.rb

@@ -24,7 +24,7 @@ def each
         end
       end
 
-      def as_json
+      def as_json(_opts = {})
         errors.map do |k, v|
           {
             params: k,
@@ -33,7 +33,7 @@ def as_json
         end
       end
 
-      def to_json
+      def to_json(_opts = {})
         as_json.to_json
       end
 

lib/grape/middleware/error.rb

@@ -58,6 +58,11 @@ def exec_handler(e, &handler)
         end
       end
 
+      def error!(message, status = options[:default_status], headers = {}, backtrace = [])
+        headers = { 'Content-Type' => content_type }.merge(headers)
+        rack_response(format_message(message, backtrace), status, headers)
+      end
+
       def handle_error(e)
         error_response(message: e.message, backtrace: e.backtrace)
       end

spec/grape/exceptions/validation_errors_spec.rb

@@ -27,7 +27,7 @@ def app
     it 'can return structured json with separate fields' do
       subject.format :json
       subject.rescue_from Grape::Exceptions::ValidationErrors do |e|
-        rack_response e.to_json, 400
+        error!(e, 400)
       end
       subject.params do
         optional :beer