adds 405 response for methods not supported on a resource instead of 404

CHANGELOG.markdown

@@ -20,6 +20,7 @@ Fixes
 * [#181](https://github.com/intridea/grape/pull/181): Fix: Corrected JSON serialization of nested hashes containing `Grape::Entity` instances - [@benrosenblum](https://github.com/benrosenblum).
 * [#203](https://github.com/intridea/grape/pull/203): Added a check to `Entity#serializable_hash` that verifies an entity exists on an object - [@adamgotterer](https://github.com/adamgotterer).
 * [#208](https://github.com/intridea/grape/pull/208): `Entity#serializable_hash` must also check if attribute is generated by a user supplied block - [@ppadron](https://github.com/ppadron).
+* [#252](https://github.com/intridea/grape/pull/252): Resources that don't respond to a requested HTTP method return 405 (Method Not Allowed) instead of 404 (Not Found) [@simulacre](https://github.com/simulacre)
 
 0.2.1 (7/11/2012)
 =================

README.markdown

@@ -411,6 +411,50 @@ redirect "/new_url"
 redirect "/new_url", :permanent => true
 ```
 
+## Allowed Methods
+
+When you add a route for a resource, a route for the HTTP OPTIONS
+method will also be added. The response to an OPTIONS request will
+include an Allow header listing the supported methods.
+
+``` ruby
+class API < Grape::API
+  get '/counter' do
+    { :counter => Counter.count }
+  end
+
+  params do
+    requires :value, :type => Integer, :desc => 'value to add to counter'
+  end
+  put '/counter' do
+    { :counter => Counter.incr(params.value) }
+  end
+end
+```
+
+``` shell
+curl -v -X OPTIONS http://localhost:3000/counter 
+
+> OPTIONS /counter HTTP/1.1
+> 
+< HTTP/1.1 204 No Content
+< Allow: OPTIONS, GET, PUT
+```
+
+
+If a request for a resource is made with an unsupported HTTP method, an
+HTTP 405 (Method Not Allowed) response will be returned.
+
+``` shell
+curl -X DELETE -v http://localhost:3000/counter/
+
+> DELETE /counter/ HTTP/1.1
+> Host: localhost:3000
+> 
+< HTTP/1.1 405 Method Not Allowed
+< Allow: OPTIONS, GET, PUT
+```
+
 ## Raising Exceptions
 
 You can abort the execution of an API method by raising errors with `error!`.

lib/grape/api.rb

@@ -414,6 +414,7 @@ def initialize
       self.class.endpoints.each do |endpoint|
         endpoint.mount_in(@route_set)
       end
+      add_head_not_allowed_methods
       @route_set.freeze
     end
 
@@ -422,5 +423,41 @@ def call(env)
     end
 
     reset!
+
+    private
+
+    # For every resource add a 'OPTIONS' route that returns an HTTP 204 response
+    # with a list of HTTP methods that can be called. Also add a route that
+    # will return an HTTP 405 response for any HTTP method that the resource
+    # cannot handle.
+    def add_head_not_allowed_methods
+      allowed_methods = Hash.new{|h,k| h[k] = [] }
+      resources       = self.class.endpoints.map do |endpoint|
+        endpoint.options[:app] && endpoint.options[:app].respond_to?(:endpoints) ?
+          endpoint.options[:app].endpoints.map(&:routes) :
+          endpoint.routes
+      end
+      resources.flatten.each do |route|
+        allowed_methods[route.route_compiled] << route.route_method
+      end
+
+      allowed_methods.each do |path_info, methods|
+        allow_header = (["OPTIONS"] | methods).join(", ")
+        unless methods.include?("OPTIONS")
+          @route_set.add_route( proc { [204, { 'Allow' => allow_header }, []]}, {
+            :path_info      => path_info,
+            :request_method => "OPTIONS"
+          })
+        end
+        not_allowed_methods = %w(GET PUT POST DELETE PATCH HEAD) - methods
+        not_allowed_methods.each do |bad_method|
+          @route_set.add_route( proc { [405, { 'Allow' => allow_header }, []]}, {
+            :path_info      => path_info,
+            :request_method => bad_method
+          })
+        end
+      end
+    end
+
   end
 end

spec/grape/api_spec.rb

@@ -301,8 +301,8 @@ def app; subject end
         send(verb, '/example')
         last_response.body.should eql verb == 'head' ? '' : verb
         # Call it with a method other than the properly constrained one.
-        send(verbs[(verbs.index(verb) + 1) % verbs.size], '/example')
-        last_response.status.should eql 404
+        send(used_verb = verbs[(verbs.index(verb) + 1) % verbs.size], '/example')
+        last_response.status.should eql used_verb == 'options' ? 204 :405
       end
     end
 
@@ -315,6 +315,36 @@ def app; subject end
       last_response.status.should eql 201
       last_response.body.should eql 'Created'
     end
+
+    it 'should return a 405 for an unsupported method' do
+      subject.get 'example' do
+        "example"
+      end
+      put '/example'
+      last_response.status.should eql 405
+      last_response.body.should eql ''
+    end
+
+    specify '405 responses should include an Allow header specifying supported methods' do
+      subject.get 'example' do
+        "example"
+      end
+      subject.post 'example' do
+        "example"
+      end
+      put '/example'
+      last_response.headers['Allow'].should eql 'OPTIONS, GET, POST'
+    end
+
+    it 'should add an OPTIONS route that returns a 204 and an Allow header' do
+      subject.get 'example' do
+        "example"
+      end
+      options '/example'
+      last_response.status.should eql 204
+      last_response.body.should eql ''
+      last_response.headers['Allow'].should eql 'OPTIONS, GET'
+    end
   end
 
   describe 'filters' do