From 7feb8481acc80ae708439b4a853be54f0228b755 Mon Sep 17 00:00:00 2001
From: Aravinth Manivannan <realaravinth@batsense.net>
Date: Thu, 28 Mar 2024 18:03:53 +0530
Subject: [PATCH] feat: cron job to rm remote actors (persons) without
 following in local instance

---
 models/federation/federation.go | 24 ++++++++++++++++++++++++
 options/locale/locale_en-US.ini |  1 +
 services/cron/tasks_basic.go    | 21 +++++++++++++++++++++
 services/forgefed/actor.go      | 28 ++++++++++++++++++++++++++++
 4 files changed, 74 insertions(+)

diff --git a/models/federation/federation.go b/models/federation/federation.go
index 6b867e8ea..ee2e64af9 100644
--- a/models/federation/federation.go
+++ b/models/federation/federation.go
@@ -3,10 +3,13 @@ package federation
 import (
 	"context"
 	"strings"
+	"time"
 
 	"code.gitea.io/gitea/models/db"
 	"code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/log"
 	"code.gitea.io/gitea/modules/setting"
+	"xorm.io/builder"
 )
 
 // HookTask represents a hook task.
@@ -161,3 +164,24 @@ func CreatUser(ctx context.Context, u *user.User) error {
 	return committer.Commit()
 
 }
+
+func GetRemoteUsersWithNoLocalFollowers(ctx context.Context, olderThan time.Duration, page int) ([]user.User, error) {
+	limit := 40
+	offset := page * limit
+	var users []user.User
+
+	err := db.GetEngine(ctx).
+		Table("user").
+		Where("num_followers = 0").
+		And(builder.Lt{"user.created_unix": time.Now().Add(-olderThan).Unix()}).
+		Join("inner", "federated_user", "federated_user.user_id = user.id").
+		Limit(limit, offset).
+		Find(&users)
+
+	if err != nil {
+		log.Trace("Error: GetRemoteUserWithNoLocalFollowers: %w", err)
+		return nil, err
+	}
+	return users, nil
+
+}
diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index 647c46b5a..8a1ed3a41 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -2921,6 +2921,7 @@ dashboard.start_schedule_tasks = Start schedule tasks
 dashboard.sync_branch.started = Branches Sync started
 dashboard.sync_tag.started = Tags Sync started
 dashboard.rebuild_issue_indexer = Rebuild issue indexer
+dashboard.remote_actor_cleanup = Clean remote actors with no local followers
 
 users.user_manage_panel = Manage user accounts
 users.new_account = Create User Account
diff --git a/services/cron/tasks_basic.go b/services/cron/tasks_basic.go
index 3869382d2..ea7dc3e8b 100644
--- a/services/cron/tasks_basic.go
+++ b/services/cron/tasks_basic.go
@@ -15,6 +15,7 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 	"code.gitea.io/gitea/services/actions"
 	"code.gitea.io/gitea/services/auth"
+	forgefed_service "code.gitea.io/gitea/services/forgefed"
 	"code.gitea.io/gitea/services/migrations"
 	mirror_service "code.gitea.io/gitea/services/mirror"
 	packages_cleanup_service "code.gitea.io/gitea/services/packages/cleanup"
@@ -187,7 +188,27 @@ func initBasicTasks() {
 	if setting.Packages.Enabled {
 		registerCleanupPackages()
 	}
+
 	if setting.Actions.Enabled {
 		registerActionsCleanup()
 	}
+
+	if setting.Federation.Enabled {
+		registerCleanupRemotePersonsWithNoFollowers()
+	}
+
+}
+
+func registerCleanupRemotePersonsWithNoFollowers() {
+	RegisterTaskFatal("remote_actor_cleanup", &OlderThanConfig{
+		BaseConfig: BaseConfig{
+			Enabled:    true,
+			RunAtStart: true,
+			Schedule:   "@midnight",
+		},
+		OlderThan: 24 * time.Hour,
+	}, func(ctx context.Context, _ *user_model.User, config Config) error {
+		acConfig := config.(*OlderThanConfig)
+		return forgefed_service.CleanUpRemotePersons(ctx, acConfig.OlderThan)
+	})
 }
diff --git a/services/forgefed/actor.go b/services/forgefed/actor.go
index e6b0eb8a8..ab10a41e3 100644
--- a/services/forgefed/actor.go
+++ b/services/forgefed/actor.go
@@ -6,9 +6,12 @@ import (
 	"fmt"
 	"io"
 	"net/http"
+	"time"
 
 	"code.gitea.io/gitea/models/federation"
 	"code.gitea.io/gitea/models/user"
+	"code.gitea.io/gitea/modules/log"
+	user_service "code.gitea.io/gitea/services/user"
 
 	ap "github.com/go-ap/activitypub"
 )
@@ -94,3 +97,28 @@ func SavePerson(ctx context.Context, person *ap.Person) (*user.User, error) {
 
 	return u, nil
 }
+
+// Clean up remote actors (persons) without any followers in local instance
+func CleanUpRemotePersons(ctx context.Context, olderThan time.Duration) error {
+	page := 0
+	for {
+		users, err := federation.GetRemoteUsersWithNoLocalFollowers(ctx, olderThan, page)
+		if len(users) == 0 {
+			break
+		}
+		if err != nil {
+			log.Trace("Error: CleanUpRemotePersons: %v", err)
+			return err
+		}
+
+		for _, u := range users {
+			err = user_service.DeleteUser(ctx, &u, false)
+			if err != nil {
+				log.Trace("Error: CleanUpRemotePersons: %v", err)
+				return err
+			}
+		}
+		page += 1
+	}
+	return nil
+}