feat_: limit number of members in a community and number of pending requests (#5107)

* feat(community): limit nb of requests to join and members

Needed for https://github.com/status-im/status-desktop/issues/14532

* chore: simplify TestRequestAccessAgain

* chore: add a test for the member limit

protocol/communities/community.go

@@ -1001,6 +1001,13 @@ func (o *Community) Edit(description *protobuf.CommunityDescription) {
 	o.config.CommunityDescription.AdminSettings.PinMessageAllMembersEnabled = description.AdminSettings.PinMessageAllMembersEnabled
 }
 
+func (o *Community) EditPermissionAccess(permissionAccess protobuf.CommunityPermissions_Access) {
+	o.config.CommunityDescription.Permissions.Access = permissionAccess
+	if o.IsControlNode() {
+		o.increaseClock()
+	}
+}
+
 func (o *Community) Join() {
 	o.config.Joined = true
 	o.config.JoinedAt = time.Now().Unix()

protocol/communities/manager.go

@@ -59,6 +59,9 @@ var pieceLength = 100 * 1024
 
 const maxArchiveSizeInBytes = 30000000
 
+var maxNbMembers = 5000
+var maxNbPendingRequestedMembers = 100
+
 var memberPermissionsCheckInterval = 1 * time.Hour
 var validateInterval = 2 * time.Minute
 
@@ -66,6 +69,12 @@ var validateInterval = 2 * time.Minute
 func SetValidateInterval(duration time.Duration) {
 	validateInterval = duration
 }
+func SetMaxNbMembers(maxNb int) {
+	maxNbMembers = maxNb
+}
+func SetMaxNbPendingRequestedMembers(maxNb int) {
+	maxNbPendingRequestedMembers = maxNb
+}
 
 // errors
 var (
@@ -1293,7 +1302,7 @@ func (m *Manager) EditCommunity(request *requests.EditCommunity) (*Community, er
 
 	newDescription, err := request.ToCommunityDescription()
 	if err != nil {
-		return nil, fmt.Errorf("Can't create community description: %v", err)
+		return nil, fmt.Errorf("can't create community description: %v", err)
 	}
 
 	// If permissions weren't explicitly set on original request, use existing ones
@@ -2645,6 +2654,14 @@ func (m *Manager) HandleCommunityRequestToJoin(signer *ecdsa.PublicKey, receiver
 		return nil, nil, err
 	}
 
+	nbPendingRequestsToJoin, err := m.persistence.GetNumberOfPendingRequestsToJoin(community.ID())
+	if err != nil {
+		return nil, nil, err
+	}
+	if nbPendingRequestsToJoin >= maxNbPendingRequestedMembers {
+		return nil, nil, errors.New("max number of requests to join reached")
+	}
+
 	requestToJoin := &RequestToJoin{
 		PublicKey:          common.PubkeyToHex(signer),
 		Clock:              request.Clock,
@@ -2737,6 +2754,15 @@ func (m *Manager) HandleCommunityRequestToJoin(signer *ecdsa.PublicKey, receiver
 			}
 		}
 
+		// Check if we reached the limit, if we did, change the community setting to be On Request
+		if community.AutoAccept() && community.MembersCount() >= maxNbMembers {
+			community.EditPermissionAccess(protobuf.CommunityPermissions_MANUAL_ACCEPT)
+			err = m.saveAndPublish(community)
+			if err != nil {
+				return nil, nil, err
+			}
+		}
+
 		// If user is already a member, then accept request automatically
 		// It may happen when member removes itself from community and then tries to rejoin
 		// More specifically, CommunityRequestToLeave may be delivered later than CommunityRequestToJoin, or not delivered at all

protocol/communities/persistence.go

@@ -842,6 +842,15 @@ func (p *Persistence) GetRequestToJoin(id []byte) (*RequestToJoin, error) {
 	return request, nil
 }
 
+func (p *Persistence) GetNumberOfPendingRequestsToJoin(communityID types.HexBytes) (int, error) {
+	var count int
+	err := p.db.QueryRow(`SELECT count(1) FROM communities_requests_to_join WHERE community_id = ? AND state = ?`, communityID, RequestToJoinStatePending).Scan(&count)
+	if err != nil {
+		return 0, err
+	}
+	return count, nil
+}
+
 func (p *Persistence) GetRequestToJoinByPkAndCommunityID(pk string, communityID []byte) (*RequestToJoin, error) {
 	request := &RequestToJoin{}
 	err := p.db.QueryRow(`SELECT id,public_key,clock,ens_name,customization_color,chat_id,community_id,state FROM communities_requests_to_join WHERE public_key = ? AND community_id = ?`, pk, communityID).Scan(&request.ID, &request.PublicKey, &request.Clock, &request.ENSName, &request.CustomizationColor, &request.ChatID, &request.CommunityID, &request.State)

protocol/communities_messenger_test.go

@@ -9,6 +9,7 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"reflect"
 	"strings"
 	"testing"
 	"time"
@@ -1658,31 +1659,7 @@ func (s *MessengerCommunitiesSuite) TestRequestAccessAgain() {
 
 	community := response.Communities()[0]
 
-	chat := CreateOneToOneChat(common.PubkeyToHex(&s.alice.identity.PublicKey), &s.alice.identity.PublicKey, s.alice.transport)
-
-	s.Require().NoError(s.bob.SaveChat(chat))
-
-	message := buildTestMessage(*chat)
-	message.CommunityID = community.IDString()
-
-	// We send a community link to alice
-	response, err = s.bob.SendChatMessage(context.Background(), message)
-	s.Require().NoError(err)
-	s.Require().NotNil(response)
-
-	// Retrieve community link & community
-	err = tt.RetryWithBackOff(func() error {
-		response, err = s.alice.RetrieveAll()
-		if err != nil {
-			return err
-		}
-		if len(response.Communities()) == 0 {
-			return errors.New("message not received")
-		}
-		return nil
-	})
-
-	s.Require().NoError(err)
+	s.advertiseCommunityTo(community, s.bob, s.alice)
 
 	request := &requests.RequestToJoinCommunity{CommunityID: community.ID()}
 	// We try to join the org
@@ -3514,6 +3491,82 @@ func (s *MessengerCommunitiesSuite) TestCommunityBanUserRequestToJoin() {
 	s.Require().ErrorContains(err, "can't request access")
 }
 
+func (s *MessengerCommunitiesSuite) TestCommunityMaxNumberOfMembers() {
+	john := s.newMessenger()
+	_, err := john.Start()
+	s.Require().NoError(err)
+
+	defer TearDownMessenger(&s.Suite, john)
+
+	// Bring back the original values
+	defer communities.SetMaxNbMembers(5000)
+	defer communities.SetMaxNbPendingRequestedMembers(100)
+
+	community, _ := s.createCommunity()
+
+	communities.SetMaxNbMembers(2)
+	communities.SetMaxNbPendingRequestedMembers(1)
+
+	s.advertiseCommunityTo(community, s.owner, s.alice)
+	s.advertiseCommunityTo(community, s.owner, s.bob)
+	s.advertiseCommunityTo(community, s.owner, john)
+
+	// Alice joins the community correctly
+	s.joinCommunity(community, s.owner, s.alice)
+
+	// Bob also tries to join, but he will be put in the requests to join to approve and won't join
+	request := &requests.RequestToJoinCommunity{CommunityID: community.ID()}
+	response, err := s.bob.RequestToJoinCommunity(request)
+	s.Require().NoError(err)
+	s.Require().NotNil(response)
+	s.Require().Len(response.RequestsToJoinCommunity(), 1)
+	requestID := response.RequestsToJoinCommunity()[0].ID
+
+	response, err = WaitOnMessengerResponse(
+		s.owner,
+		func(r *MessengerResponse) bool {
+			for _, req := range r.RequestsToJoinCommunity() {
+				if reflect.DeepEqual(req.ID, requestID) {
+					return true
+				}
+			}
+			return false
+		},
+		"no request to join",
+	)
+	s.Require().NoError(err)
+	s.Require().Len(response.RequestsToJoinCommunity(), 1)
+	s.Require().Equal(communities.RequestToJoinStatePending, response.RequestsToJoinCommunity()[0].State)
+
+	// We confirm that there are still 2 members only and the access setting is now manual
+	updatedCommunity, err := s.owner.communitiesManager.GetByID(community.ID())
+	s.Require().NoError(err)
+	s.Require().Len(updatedCommunity.Members(), 2)
+	s.Require().Equal(protobuf.CommunityPermissions_MANUAL_ACCEPT, updatedCommunity.Permissions().Access)
+
+	// John also tries to join, but he his request will be ignored as it exceeds the max number of pending requests
+	requestJohn := &requests.RequestToJoinCommunity{CommunityID: community.ID()}
+	response, err = john.RequestToJoinCommunity(requestJohn)
+	s.Require().NoError(err)
+	s.Require().NotNil(response)
+	s.Require().Len(response.RequestsToJoinCommunity(), 1)
+	requestJohnID := response.RequestsToJoinCommunity()[0].ID
+
+	_, err = WaitOnMessengerResponse(
+		s.owner,
+		func(r *MessengerResponse) bool {
+			for _, req := range r.RequestsToJoinCommunity() {
+				if reflect.DeepEqual(req.ID, requestJohnID) {
+					return true
+				}
+			}
+			return false
+		},
+		"no request to join",
+	)
+	s.Require().Error(err)
+}
+
 func (s *MessengerCommunitiesSuite) TestHandleImport() {
 	community, chat := s.createCommunity()