partial fix for missing LastSeen in p2p topics

server/datamodel.go

@@ -399,6 +399,9 @@ type MsgTopicDesc struct {
 	// If the group topic is online.
 	Online bool `json:"online,omitempty"`
 
+	// P2P other user's last online timestamp & user agent
+	LastSeen *MsgLastSeenInfo `json:"seen,omitempty"`
+
 	DefaultAcs *MsgDefaultAcsMode `json:"defacs,omitempty"`
 	// Actual access mode
 	Acs *MsgAccessMode `json:"acs,omitempty"`
@@ -484,7 +487,7 @@ type MsgTopicSub struct {
 	// Id of the latest Delete operation
 	DelId int `json:"clear,omitempty"`
 
-	// P2P topics only:
+	// P2P topics in 'me' {get subs} response:
 
 	// Other user's last online timestamp & user agent
 	LastSeen *MsgLastSeenInfo `json:"seen,omitempty"`

server/db/mongodb/adapter.go

@@ -1335,8 +1335,10 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			uid1, uid2, _ := t.ParseP2P(sub.Topic)
 			if uid1 == uid {
 				usrq = append(usrq, uid2.String())
+				sub.SetWith(uid2.UserId())
 			} else {
 				usrq = append(usrq, uid1.String())
+				sub.SetWith(uid1.UserId())
 			}
 			topq = append(topq, tname)
 		} else {
@@ -1410,16 +1412,7 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			filter["state"] = b.M{"$ne": t.StateDeleted}
 		}
 
-		if !ims.IsZero() {
-			// Use cache timestamp if provided: get newer entries only.
-			filter["updatedat"] = b.M{"$gt": ims}
-
-			findOpts = nil
-			if limit > 0 && limit < len(topq) {
-				// No point in fetching more than the requested limit.
-				findOpts = mdbopts.Find().SetLimit(int64(limit))
-			}
-		}
+		// Ignoring ims: we need all users to get LastSeen and UserAgent.
 
 		cur, err = a.db.Collection("users").Find(a.ctx, filter, findOpts)
 		if err != nil {

server/db/mysql/adapter.go

@@ -1592,17 +1592,7 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			args = append(args, t.StateDeleted)
 		}
 
-		if !ims.IsZero() {
-			// Use cache timestamp if provided: get newer entries only.
-			q += " AND updatedat>?"
-			args = append(args, ims)
-
-			if limit > 0 && limit < len(usrq) {
-				// No point in fetching more than the requested limit.
-				q += " ORDER BY updatedat LIMIT ?"
-				args = append(args, limit)
-			}
-		}
+		// Ignoring ims: we need all users to get LastSeen and UserAgent.
 
 		q = a.db.Rebind(q)
 

server/db/rethinkdb/adapter.go

@@ -1141,8 +1141,10 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			uid1, uid2, _ := t.ParseP2P(sub.Topic)
 			if uid1 == uid {
 				usrq = append(usrq, uid2.String())
+				sub.SetWith(uid2.UserId())
 			} else {
 				usrq = append(usrq, uid1.String())
+				sub.SetWith(uid1.UserId())
 			}
 			topq = append(topq, tname)
 		} else {
@@ -1220,15 +1222,7 @@ func (a *adapter) TopicsForUser(uid t.Uid, keepDeleted bool, opts *t.QueryOpt) (
 			q = q.Filter(rdb.Row.Field("State").Eq(t.StateDeleted).Not())
 		}
 
-		if !ims.IsZero() {
-			// Use cache timestamp if provided: get newer entries only.
-			q = q.Filter(rdb.Row.Field("UpdatedAt").Gt(ims))
-
-			if limit > 0 && limit < len(topq) {
-				// No point in fetching more than the requested limit.
-				q = q.OrderBy("UpdatedAt").Limit(limit)
-			}
-		}
+		// Ignoring ims: we need all users to get LastSeen and UserAgent.
 
 		cursor, err = q.Run(a.conn)
 		if err != nil {

server/init_topic.go

@@ -276,8 +276,10 @@ func initTopicP2P(t *Topic, sreg *sessionJoin) error {
 
 			uid := types.ParseUid(subs[i].User)
 			t.perUser[uid] = perUserData{
-				// Adapter already swapped the public values
+				// Adapter has already swapped the state, public, defaultAccess, lastSeen values.
 				public:    subs[i].GetPublic(),
+				lastSeen:  subs[i].GetLastSeen(),
+				lastUA:    subs[i].GetUserAgent(),
 				topicName: types.ParseUid(subs[(i+1)%2].User).UserId(),
 
 				private:   subs[i].Private,

server/topic.go

@@ -134,6 +134,8 @@ type perUserData struct {
 
 	// P2P only:
 	public    interface{}
+	lastSeen  time.Time
+	lastUA    string
 	topicName string
 	deleted   bool
 
@@ -1875,9 +1877,24 @@ func (t *Topic) replyGetDesc(sess *Session, asUid types.Uid, asChan bool, opts *
 			desc.State = types.StateOK.String()
 		}
 
-		if t.cat == types.TopicCatGrp && (pud.modeGiven & pud.modeWant).IsPresencer() {
-			desc.Online = t.isOnline()
+		if (pud.modeGiven & pud.modeWant).IsPresencer() {
+			if t.cat == types.TopicCatGrp {
+				desc.Online = t.isOnline()
+			} else if t.cat == types.TopicCatP2P {
+				// This is the timestamp when the other user logged off last time.
+				// It does not change while the topic is loaded into memory and that's OK most of the time
+				// because to stay in memory at least one of the users must be connected to topic.
+				// FIXME(gene): it breaks when user A stays active in one session and connects-disconnects
+				// from another session. The second session will not see correct LastSeen time and UserAgent.
+				if !pud.lastSeen.IsZero() {
+					desc.LastSeen = &MsgLastSeenInfo{
+						When:      &pud.lastSeen,
+						UserAgent: pud.lastUA,
+					}
+				}
+			}
 		}
+
 		if ifUpdated {
 			desc.Private = pud.private
 		}
@@ -2299,14 +2316,6 @@ func (t *Topic) replyGetSub(sess *Session, asUid types.Uid, authLevel auth.Level
 					if t.cat == types.TopicCatGrp {
 						pud := t.perUser[uid]
 						mts.Online = pud.online > 0 && presencer
-					} else if t.cat == types.TopicCatP2P {
-						lastSeen := sub.GetLastSeen()
-						if !lastSeen.IsZero() {
-							mts.LastSeen = &MsgLastSeenInfo{
-								When:      &lastSeen,
-								UserAgent: sub.GetUserAgent(),
-							}
-						}
 					}
 				}
 			}