Makes sure Grape::API behaves as a Rack::App (ruby-grape#1893)

Makes sure Grape::API behaves as a Rack::App by calling: 'call' on the first mounted instance rather than the base instance (which is never mounted) which will have the environment information as to where it was mounted.

CHANGELOG.md

@@ -7,6 +7,7 @@
 #### Fixes
 
 * Your contribution here.
+* [#1893](https://github.com/ruby-grape/grape/pull/1893): Allows `Grape::API` to behave like a Rack::app in some instances where it was misbehaving - [@myxoh](https://github.com/myxoh).
 
 ### 1.2.4 (2019/06/13)
 

lib/grape/api.rb

@@ -48,7 +48,12 @@ def override_all_methods!
  # (http://www.rubydoc.info/github/rack/rack/master/file/SPEC) for more.
  # NOTE: This will only be called on an API directly mounted on RACK
  def call(*args, &block)
- base_instance.call(*args, &block)
+ instance_for_rack = if never_mounted?
+ base_instance
+ else
+ mounted_instances.first
+ end
+ instance_for_rack.call(*args, &block)
  end
 
  # Allows an API to itself be inheritable:
@@ -147,6 +152,14 @@ def evaluate_arguments(configuration, *args)
  end
  end
  end
+
+ def never_mounted?
+ mounted_instances.empty?
+ end
+
+ def mounted_instances
+ instances - [base_instance]
+ end
  end
  end
 end

spec/grape/integration/rack_spec.rb

@@ -31,4 +31,26 @@
  input.unlink
  end
  end
+
+ context 'when the app is mounted' do
+ def app
+ @main_app ||= Class.new(Grape::API) do
+ get 'ping'
+ end
+ end
+
+ let!(:base) do
+ app_to_mount = app
+ Class.new(Grape::API) do
+ namespace 'namespace' do
+ mount app_to_mount
+ end
+ end
+ end
+
+ it 'finds the app on the namespace' do
+ get '/namespace/ping'
+ expect(last_response.status).to eq 200
+ end
+ end
 end