Merge pull request #1201 from marshall-lee/rack_builder_used_right

Don't call builder on every request.

Author: dblock

.rubocop_todo.yml

@@ -13,7 +13,7 @@ Lint/NestedMethodDefinition:
 
 # Offense count: 37
 Metrics/AbcSize:
-  Max: 46
+  Max: 51
 
 # Offense count: 1
 Metrics/BlockNesting:
@@ -36,7 +36,7 @@ Metrics/LineLength:
 # Offense count: 42
 # Configuration parameters: CountComments.
 Metrics/MethodLength:
-  Max: 35
+  Max: 36
 
 # Offense count: 8
 # Configuration parameters: CountComments.

lib/grape/endpoint.rb

@@ -188,20 +188,16 @@ def compile_path(prepared_path, anchor = true, requirements = {})
     end
 
     def call(env)
+      build_app
       dup.call!(env)
     end
 
     def call!(env)
       extend helpers
 
       env[Grape::Env::API_ENDPOINT] = self
-      if options[:app]
-        options[:app].call(env)
-      else
-        builder = build_middleware
-        builder.run ->(arg) { run(arg) }
-        builder.call(env)
-      end
+      @env = env
+      @app.call(env)
     end
 
     # Return the collection of endpoints within this endpoint.
@@ -216,9 +212,8 @@ def equals?(e)
 
     protected
 
-    def run(env)
+    def run
       ActiveSupport::Notifications.instrument('endpoint_run.grape', endpoint: self, env: env) do
-        @env = env
         @header = {}
 
         @request = Grape::Request.new(env)
@@ -262,7 +257,11 @@ def run(env)
       end
     end
 
-    def build_middleware
+    def build_app
+      @app ||= options[:app] || build_stack
+    end
+
+    def build_stack
       b = Rack::Builder.new
 
       b.use Rack::Head
@@ -303,7 +302,9 @@ def build_middleware
             formatters: Grape::DSL::Configuration.stacked_hash_to_hash(namespace_stackable(:formatters)),
             parsers: Grape::DSL::Configuration.stacked_hash_to_hash(namespace_stackable(:parsers))
 
-      b
+      b.run ->(env) { env[Grape::Env::API_ENDPOINT].run }
+
+      b.to_app
     end
 
     def helpers