1 files changed, 53 insertions, 0 deletions
diff --git a/lib/api/v3/subscriptions.rb b/lib/api/v3/subscriptions.rb
new file mode 100644
index 00000000000..02a4157c26e
--- /dev/null
+++ b/lib/api/v3/subscriptions.rb
@@ -0,0 +1,53 @@
+module API
+  module V3
+    class Subscriptions < Grape::API
+      before { authenticate! }
+
+      subscribable_types = {
+        'merge_request' => proc { |id| find_merge_request_with_access(id, :update_merge_request) },
+        'merge_requests' => proc { |id| find_merge_request_with_access(id, :update_merge_request) },
+        'issues' => proc { |id| find_project_issue(id) },
+        'labels' => proc { |id| find_project_label(id) },
+      }
+
+      params do
+        requires :id, type: String, desc: 'The ID of a project'
+        requires :subscribable_id, type: String, desc: 'The ID of a resource'
+      end
+      resource :projects do
+        subscribable_types.each do |type, finder|
+          type_singularized = type.singularize
+          entity_class = ::API::Entities.const_get(type_singularized.camelcase)
+
+          desc 'Subscribe to a resource' do
+            success entity_class
+          end
+          post ":id/#{type}/:subscribable_id/subscription" do
+            resource = instance_exec(params[:subscribable_id], &finder)
+
+            if resource.subscribed?(current_user, user_project)
+              not_modified!
+            else
+              resource.subscribe(current_user, user_project)
+              present resource, with: entity_class, current_user: current_user, project: user_project
+            end
+          end
+
+          desc 'Unsubscribe from a resource' do
+            success entity_class
+          end
+          delete ":id/#{type}/:subscribable_id/subscription" do
+            resource = instance_exec(params[:subscribable_id], &finder)
+
+            if !resource.subscribed?(current_user, user_project)
+              not_modified!
+            else
+              resource.unsubscribe(current_user, user_project)
+              present resource, with: entity_class, current_user: current_user, project: user_project
+            end
+          end
+        end
+      end
+    end
+  end
+end