Add subscription API for the group label API

lib/api/entities.rb

@@ -1019,12 +1019,12 @@ module API
         label.open_merge_requests_count(options[:current_user])
       end
-      expose :priority do |label, options|
+      expose :priority, if: lambda { |_, options| options[:project].is_a?(::Project) }  do |label, options|
         label.priority(options[:project])
       end
       expose :subscribed do |label, options|
-        label.subscribed?(options[:current_user], options[:parent])
+        label.subscribed?(options[:current_user], options[:project])
       end
     end

lib/api/helpers.rb

@@ -170,8 +170,8 @@ module API
       end
     end
-    def find_project_label(id)
-      labels = available_labels_for(user_project)
+    def find_label(parent, id)
+      labels = available_labels_for(parent)
       label = labels.find_by_id(id) || labels.find_by_title(id)
       label || not_found!('Label')

lib/api/subscriptions.rb

@@ -4,11 +4,12 @@ module API
   class Subscriptions < Grape::API
     before { authenticate! }
-    subscribable_types = {
-      '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) }
-    }
+    subscribables = [
+      ['merge_requests', Project, proc { |id| find_merge_request_with_access(id, :update_merge_request) }, proc { user_project }],
+      ['issues', Project, proc { |id| find_project_issue(id) }, proc { user_project }],
+      ['labels', Project, proc { |id| find_label(user_project, id) }, proc { user_project }],
+      ['labels', Group, proc { |id| find_label(user_group, id) }, proc { nil }]
+    ]
     params do
       requires :id, type: String, desc: 'The ID of a project'
@@ -19,17 +20,27 @@ module API
         type_singularized = type.singularize
         entity_class = Entities.const_get(type_singularized.camelcase)
+    subscribables.each do |subscribable|
+      source_type = subscribable[:source].name.underscore
+      entity_class = Entities.const_get(subscribable[:type].singularize.camelcase)
+
+      params do
+        requires :id, type: String, desc: "The #{source_type} ID"
+        requires :subscribable_id, type: String, desc: 'The ID of a resource'
+      end
+      resource source_type.pluralize, requirements: API::NAMESPACE_OR_PROJECT_REQUIREMENTS do
         desc 'Subscribe to a resource' do
           success entity_class
         end
         post ":id/#{type}/:subscribable_id/subscribe" do
+          parent = instance_exec(&parent_ressource)
           resource = instance_exec(params[:subscribable_id], &finder)
-          if resource.subscribed?(current_user, user_project)
+          if resource.subscribed?(current_user, parent)
             not_modified!
           else
-            resource.subscribe(current_user, user_project)
-            present resource, with: entity_class, current_user: current_user, project: user_project
+            resource.subscribe(current_user, parent)
+            present resource, with: entity_class, current_user: current_user, project: parent
           end
         end
@@ -37,13 +48,15 @@ module API
           success entity_class
         end
         post ":id/#{type}/:subscribable_id/unsubscribe" do
+          parent = instance_exec(&parent_ressource)
           resource = instance_exec(params[:subscribable_id], &finder)
-          if !resource.subscribed?(current_user, user_project)
+
+          if !resource.subscribed?(current_user, parent)
             not_modified!
           else
-            resource.unsubscribe(current_user, user_project)
-            present resource, with: entity_class, current_user: current_user, project: user_project
+            resource.unsubscribe(current_user, parent)
+            present resource, with: entity_class, current_user: current_user, project: parent
           end
         end
       end

spec/requests/api/group_labels_spec.rb

@@ -209,4 +209,92 @@ describe API::GroupLabels do
       expect(json_response['message']['color']).to eq(['must be a valid color code'])
     end
   end
-end
\ No newline at end of file
+
+  describe 'POST /groups/:id/labels/:label_id/subscribe' do
+    context 'when label_id is a label title' do
+      it 'subscribes to the label' do
+        post api("/groups/#{group.id}/labels/#{label1.title}/subscribe", user)
+
+        expect(response).to have_gitlab_http_status(201)
+        expect(json_response['name']).to eq(label1.title)
+        expect(json_response['subscribed']).to be_truthy
+      end
+    end
+
+    context 'when label_id is a label ID' do
+      it 'subscribes to the label' do
+        post api("/groups/#{group.id}/labels/#{label1.id}/subscribe", user)
+
+        expect(response).to have_gitlab_http_status(201)
+        expect(json_response['name']).to eq(label1.title)
+        expect(json_response['subscribed']).to be_truthy
+      end
+    end
+
+    context 'when user is already subscribed to label' do
+      before do
+        label1.subscribe(user)
+      end
+
+      it 'returns 304' do
+        post api("/groups/#{group.id}/labels/#{label1.id}/subscribe", user)
+
+        expect(response).to have_gitlab_http_status(304)
+      end
+    end
+
+    context 'when label ID is not found' do
+      it 'returns 404 error' do
+        post api("/groups/#{group.id}/labels/1234/subscribe", user)
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+  end
+
+  describe 'POST /groups/:id/labels/:label_id/unsubscribe' do
+    before do
+      label1.subscribe(user)
+    end
+
+    context 'when label_id is a label title' do
+      it 'unsubscribes from the label' do
+        post api("/groups/#{group.id}/labels/#{label1.title}/unsubscribe", user)
+
+        expect(response).to have_gitlab_http_status(201)
+        expect(json_response['name']).to eq(label1.title)
+        expect(json_response['subscribed']).to be_falsey
+      end
+    end
+
+    context 'when label_id is a label ID' do
+      it 'unsubscribes from the label' do
+        post api("/groups/#{group.id}/labels/#{label1.id}/unsubscribe", user)
+
+        expect(response).to have_gitlab_http_status(201)
+        expect(json_response['name']).to eq(label1.title)
+        expect(json_response['subscribed']).to be_falsey
+      end
+    end
+
+    context 'when user is already unsubscribed from label' do
+      before do
+        label1.unsubscribe(user)
+      end
+
+      it 'returns 304' do
+        post api("/groups/#{group.id}/labels/#{label1.id}/unsubscribe", user)
+
+        expect(response).to have_gitlab_http_status(304)
+      end
+    end
+
+    context 'when label ID is not found' do
+      it 'returns 404 error' do
+        post api("/groups/#{group.id}/labels/1234/unsubscribe", user)
+
+        expect(response).to have_gitlab_http_status(404)
+      end
+    end
+  end
+end