Add header support for middleware

Extract #headers from DSL::InsideRoute to DSL::Headers

.rubocop_todo.yml

@@ -1,16 +1,11 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2015-11-23 18:15:01 -0500 using RuboCop version 0.35.1.
+# on 2016-01-15 12:33:35 +0900 using RuboCop version 0.35.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 1
-Lint/DuplicatedKey:
-  Exclude:
-    - 'spec/grape/validations_spec.rb'
-
 # Offense count: 1
 Lint/NestedMethodDefinition:
   Exclude:
@@ -33,12 +28,12 @@ Metrics/ClassLength:
 Metrics/CyclomaticComplexity:
   Max: 14
 
-# Offense count: 750
+# Offense count: 760
 # Configuration parameters: AllowURI, URISchemes.
 Metrics/LineLength:
   Max: 215
 
-# Offense count: 44
+# Offense count: 45
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
   Max: 36
@@ -62,7 +57,7 @@ Style/BlockDelimiters:
     - 'spec/grape/middleware/versioner/header_spec.rb'
     - 'spec/grape/request_spec.rb'
 
-# Offense count: 105
+# Offense count: 106
 # Configuration parameters: Exclude.
 Style/Documentation:
   Enabled: false

CHANGELOG.md

@@ -7,6 +7,7 @@
 * [#1232](https://github.com/ruby-grape/grape/pull/1232): Helpers are now available inside `rescue_from` - [@namusyaka](https://github.com/namusyaka).
 * [#1237](https://github.com/ruby-grape/grape/pull/1237): Allow multiple parameters in `given`, which behaves as if the scopes were nested in the inputted order - [@ochagata](https://github.com/ochagata).
 * [#1238](https://github.com/ruby-grape/grape/pull/1238): Call `after` of middleware on error - [@namusyaka](https://github.com/namusyaka).
+* [#1243](https://github.com/ruby-grape/grape/pull/1243): Add `header` support for middleware - [@namusyaka](https://github.com/namusyaka).
 * Your contribution here.
 
 #### Fixes

lib/grape/dsl/headers.rb

@@ -0,0 +1,16 @@
+module Grape
+  module DSL
+    module Headers
+      # Set an individual header or retrieve
+      # all headers that have been set.
+      def header(key = nil, val = nil)
+        if key
+          val ? header[key.to_s] = val : header.delete(key.to_s)
+        else
+          @header ||= {}
+        end
+      end
+      alias_method :headers, :header
+    end
+  end
+end

lib/grape/dsl/inside_route.rb

@@ -1,10 +1,12 @@
 require 'active_support/concern'
+require 'grape/dsl/headers'
 
 module Grape
   module DSL
     module InsideRoute
       extend ActiveSupport::Concern
       include Grape::DSL::Settings
+      include Grape::DSL::Headers
 
       # Denotes a situation where a DSL method has been invoked in a
       # filter which it should not yet be available in
@@ -138,16 +140,6 @@ def status(status = nil)
         end
       end
 
-      # Set an individual header or retrieve
-      # all headers that have been set.
-      def header(key = nil, val = nil)
-        if key
-          val ? @header[key.to_s] = val : @header.delete(key.to_s)
-        else
-          @header
-        end
-      end
-
       # Set response content-type
       def content_type(val = nil)
         if val

lib/grape/middleware/base.rb

@@ -1,9 +1,13 @@
+require 'grape/dsl/headers'
+
 module Grape
   module Middleware
     class Base
       attr_reader :app, :env, :options
       TEXT_HTML = 'text/html'.freeze
 
+      include Grape::DSL::Headers
+
       # @param [Rack Application] app The standard argument for a Rack middleware.
       # @param [Hash] options A hash of options, simply stored for use by subclasses.
       def initialize(app, options = {})
@@ -27,7 +31,10 @@ def call!(env)
         ensure
           after_response = after
         end
-        after_response || @app_response
+
+        response = after_response || @app_response
+        merge_headers response
+        response
       end
 
       # @abstract
@@ -65,6 +72,16 @@ def mime_types
         end
         types_without_params
       end
+
+      private
+
+      def merge_headers(response)
+        return unless headers.is_a?(Hash)
+        case response
+        when Rack::Response then response.headers.merge!(headers)
+        when Array          then response[1].merge!(headers)
+        end
+      end
     end
   end
 end

spec/grape/dsl/headers_spec.rb

@@ -0,0 +1,32 @@
+require 'spec_helper'
+
+module Grape
+  module DSL
+    module HeadersSpec
+      class Dummy
+        include Grape::DSL::Headers
+      end
+    end
+    describe Headers do
+      subject { HeadersSpec::Dummy.new }
+
+      describe '#header' do
+        describe 'set' do
+          before do
+            subject.header 'Name', 'Value'
+          end
+
+          it 'returns value' do
+            expect(subject.header['Name']).to eq 'Value'
+            expect(subject.header('Name')).to eq 'Value'
+          end
+        end
+
+        it 'returns nil' do
+          expect(subject.header['Name']).to be nil
+          expect(subject.header('Name')).to be nil
+        end
+      end
+    end
+  end
+end

spec/grape/dsl/inside_route_spec.rb

@@ -128,24 +128,6 @@ def initialize
         end
       end
 
-      describe '#header' do
-        describe 'set' do
-          before do
-            subject.header 'Name', 'Value'
-          end
-
-          it 'returns value' do
-            expect(subject.header['Name']).to eq 'Value'
-            expect(subject.header('Name')).to eq 'Value'
-          end
-        end
-
-        it 'returns nil' do
-          expect(subject.header['Name']).to be nil
-          expect(subject.header('Name')).to be nil
-        end
-      end
-
       describe '#content_type' do
         describe 'set' do
           before do

spec/grape/middleware/base_spec.rb

@@ -118,4 +118,66 @@ def default_options
       end
     end
   end
+
+  context 'header' do
+    module HeaderSpec
+      class ExampleWare < Grape::Middleware::Base
+        def before
+          header 'X-Test-Before', 'Hi'
+        end
+
+        def after
+          header 'X-Test-After', 'Bye'
+          nil
+        end
+      end
+    end
+
+    def app
+      Rack::Builder.app do
+        use HeaderSpec::ExampleWare
+        run ->(_) { [200, {}, ['Yeah']] }
+      end
+    end
+
+    it 'is able to set a header' do
+      get '/'
+      expect(last_response.headers['X-Test-Before']).to eq('Hi')
+      expect(last_response.headers['X-Test-After']).to eq('Bye')
+    end
+  end
+
+  context 'header overwrite' do
+    module HeaderOverwritingSpec
+      class ExampleWare < Grape::Middleware::Base
+        def before
+          header 'X-Test-Overwriting', 'Hi'
+        end
+
+        def after
+          header 'X-Test-Overwriting', 'Bye'
+          nil
+        end
+      end
+
+      class API < Grape::API
+        get('/') do
+          header 'X-Test-Overwriting', 'Yeah'
+          'Hello'
+        end
+      end
+    end
+
+    def app
+      Rack::Builder.app do
+        use HeaderOverwritingSpec::ExampleWare
+        run HeaderOverwritingSpec::API.new
+      end
+    end
+
+    it 'overwrites header by after headers' do
+      get '/'
+      expect(last_response.headers['X-Test-Overwriting']).to eq('Bye')
+    end
+  end
 end