Conditionally destroy a ressource

Author: Razer6

lib/api/access_requests.rb

@@ -67,13 +67,12 @@ class AccessRequests < Grape::API
         end
         delete ":id/access_requests/:user_id" do
           source = find_source(source_type, params[:id])
-          member = source.public_send(:requesters).find_by!(user_id: params[:user_id])
+          member = source.requesters.find_by!(user_id: params[:user_id])
 
-          check_unmodified_since(member.updated_at)
-
-          status 204
-          ::Members::DestroyService.new(source, current_user, params)
-            .execute(:requesters)
+          destroy_conditionally!(member) do
+            ::Members::DestroyService.new(source, current_user, params)
+              .execute(:requesters)
+          end
         end
       end
     end

lib/api/award_emoji.rb

@@ -85,12 +85,10 @@ class AwardEmoji < Grape::API
           end
           delete "#{endpoint}/:award_id" do
             award = awardable.award_emoji.find(params[:award_id])
-            check_unmodified_since(award.updated_at)
 
             unauthorized! unless award.user == current_user || current_user.admin?
 
-            status 204
-            award.destroy
+            destroy_conditionally!(award)
           end
         end
       end

lib/api/boards.rb

@@ -122,14 +122,13 @@ def board_lists
         end
         delete "/lists/:list_id" do
           authorize!(:admin_list, user_project)
-
           list = board_lists.find(params[:list_id])
-          check_unmodified_since(list.updated_at)
-
-          service = ::Boards::Lists::DestroyService.new(user_project, current_user)
 
-          unless service.execute(list)
-            render_api_error!({ error: 'List could not be deleted!' }, 400)
+          destroy_conditionally!(list) do |list|
+            service = ::Boards::Lists::DestroyService.new(user_project, current_user)
+            unless service.execute(list)
+              render_api_error!({ error: 'List could not be deleted!' }, 400)
+            end
           end
         end
       end

lib/api/broadcast_messages.rb

@@ -90,10 +90,8 @@ def find_message
       end
       delete ':id' do
         message = find_message
-        check_unmodified_since(message.updated_at)
 
-        status 204
-        message.destroy
+        destroy_conditionally!(message)
       end
     end
   end

lib/api/deploy_keys.rb

@@ -125,10 +125,7 @@ class DeployKeys < Grape::API
         key = user_project.deploy_keys_projects.find_by(deploy_key_id: params[:key_id])
         not_found!('Deploy Key') unless key
 
-        check_unmodified_since(key.updated_at)
-
-        status 204
-        key.destroy
+        destroy_conditionally!(key)
       end
     end
   end

lib/api/environments.rb

@@ -78,10 +78,8 @@ class Environments < Grape::API
         authorize! :update_environment, user_project
 
         environment = user_project.environments.find(params[:environment_id])
-        check_unmodified_since(environment.updated_at)
 
-        status 204
-        environment.destroy
+        destroy_conditionally!(environment)
       end
 
       desc 'Stops an existing environment' do

lib/api/groups.rb

@@ -117,11 +117,10 @@ def present_groups(groups, options = {})
       delete ":id" do
         group = find_group!(params[:id])
         authorize! :admin_group, group
-        
-        check_unmodified_since(group.updated_at)
 
-        status 204
-        ::Groups::DestroyService.new(group, current_user).execute
+        destroy_conditionally!(group) do |group|
+          ::Groups::DestroyService.new(group, current_user).execute
+        end
       end
 
       desc 'Get a list of projects in this group.' do

lib/api/helpers.rb

@@ -11,14 +11,25 @@ def declared_params(options = {})
       declared(params, options).to_h.symbolize_keys
     end
 
-    def check_unmodified_since(last_modified)
-      if_unmodified_since = Time.parse(headers['If-Unmodified-Since']) if headers.key?('If-Unmodified-Since') rescue nil
+    def check_unmodified_since!(last_modified)
+      if_unmodified_since = Time.parse(headers['If-Unmodified-Since']) rescue nil
 
-      if if_unmodified_since && if_unmodified_since < last_modified
+      if if_unmodified_since && last_modified > if_unmodified_since
         render_api_error!('412 Precondition Failed', 412)
       end
     end
 
+    def destroy_conditionally!(resource, last_update_field: :updated_at)
+      check_unmodified_since!(resource.public_send(last_update_field))
+
+      status 204
+      if block_given?
+        yield resource
+      else
+        resource.destroy
+      end
+    end
+
     def current_user
       return @current_user if defined?(@current_user)
 

lib/api/issues.rb

@@ -230,10 +230,8 @@ def find_issues(args = {})
         not_found!('Issue') unless issue
 
         authorize!(:destroy_issue, issue)
-        check_unmodified_since(issue.updated_at)
 
-        status 204
-        issue.destroy
+        destroy_conditionally!(issue)
       end
 
       desc 'List merge requests closing issue'  do

lib/api/labels.rb

@@ -56,10 +56,7 @@ class Labels < Grape::API
         label = user_project.labels.find_by(title: params[:name])
         not_found!('Label') unless label
 
-        check_unmodified_since(label.updated_at)
-
-        status 204
-        label.destroy
+        destroy_conditionally!(label)
       end
 
       desc 'Update an existing label. At least one optional parameter is required.' do