Make versioner consider the mount destination path

CHANGELOG.md

@@ -1,5 +1,10 @@
 ### 0.19.2 (Next)
 
+#### Fixes
+
+* [#1570](https://github.com/ruby-grape/grape/pull/1570): Make versioner consider the mount destination path - [@namusyaka](https://github.com/namusyaka).
+* Your contribution here.
+
 #### Features
 
 * [#1555](https://github.com/ruby-grape/grape/pull/1555): Added code coverage w/Coveralls - [@dblock](https://github.com/dblock).

lib/grape/endpoint.rb

@@ -295,7 +295,8 @@ def build_stack(helpers)
         stack.use Grape::Middleware::Versioner.using(namespace_inheritable(:version_options)[:using]),
                   versions: namespace_inheritable(:version) ? namespace_inheritable(:version).flatten : nil,
                   version_options: namespace_inheritable(:version_options),
-                  prefix: namespace_inheritable(:root_prefix)
+                  prefix: namespace_inheritable(:root_prefix),
+                  mount_path: namespace_stackable(:mount_path)[0]
       end
 
       stack.use Grape::Middleware::Formatter,

lib/grape/middleware/versioner/path.rb

@@ -25,6 +25,7 @@ def default_options
 
         def before
           path = env[Grape::Http::Headers::PATH_INFO].dup
+          path.sub!(mount_path, '') if mount_path && path.start_with?(mount_path)
 
           if prefix && path.index(prefix) == 0 # rubocop:disable all
             path.sub!(prefix, '')
@@ -40,6 +41,10 @@ def before
 
         private
 
+        def mount_path
+          @mount_path ||= (options[:mount_path] && options[:mount_path] != '/') ? options[:mount_path] : ''
+        end
+
         def prefix
           Grape::Router.normalize_path(options[:prefix].to_s) if options[:prefix]
         end

spec/grape/api_spec.rb

@@ -3090,6 +3090,33 @@ def static
         versioned_get '/users/hello', 'two', using: :header, vendor: 'test'
         expect(last_response.body).to eq('two')
       end
+
+      it 'recognizes potential versions with mounted path' do
+        a = Class.new(Grape::API) do
+          version :v1, using: :path
+
+          get '/hello' do
+            'hello'
+          end
+        end
+
+        b = Class.new(Grape::API) do
+          version :v1, using: :path
+
+          get '/world' do
+            'world'
+          end
+        end
+
+        subject.mount a => '/one'
+        subject.mount b => '/two'
+
+        get '/one/v1/hello'
+        expect(last_response.status).to eq 200
+
+        get '/two/v1/world'
+        expect(last_response.status).to eq 200
+      end
     end
   end
 

spec/grape/middleware/versioner/path_spec.rb

@@ -48,4 +48,11 @@
       expect(subject.call('PATH_INFO' => '/v3/foo').last).to eq('v3')
     end
   end
+
+  context 'with mount path' do
+    let(:options) { { mount_path: '/mounted', versions: [:v1] } }
+    it 'recognizes potential version' do
+      expect(subject.call('PATH_INFO' => '/mounted/v1/foo').last).to eq('v1')
+    end
+  end
 end