我使用 Firebase 离线功能，特别是我用它来确定用户上次在线或他在线的时间。我在测试的时候遇到这样一个问题，如果我注销了，Disconnect 功能就不起作用了，虽然我没有取消Disconnect 功能。我明白在注销之前，我可以自己发送这个数据，但是之后这个函数的意思就会从盒子里消失。告诉我如何解决这个问题？

此函数确定用户的事件，我在 MainTabBarController 中调用它(它用作根 Controller )

func setupLastSeenActivity() {
        DispatchQueue.main.async {
            let realmManager = RealmManager()
            guard let currentUserID = realmManager.getCurrentUser()?.id else { return }
            DispatchQueue.global(qos: .background).async {
                let ref = Database.database().reference().child(MainGateways.users.rawValue).child(currentUserID)
                let userSearchLocationRef = Database.database().reference().child(UserSearchLocationKeys.userSearchLocationModel.rawValue).child(currentUserID)

                let parameters = [UserSubgateways.isOnline.rawValue : true]
                ref.updateChildValues(parameters, withCompletionBlock: { (error, ref) in

                })

                userSearchLocationRef.updateChildValues(parameters, withCompletionBlock: { (error, ref) in

                })

                let disconnectParameters = [UserSubgateways.isOnline.rawValue : false, UserSubgateways.lastSeenTimeStamp.rawValue : ServerValue.timestamp()] as [String : Any]

                ref.onDisconnectUpdateChildValues(disconnectParameters, withCompletionBlock: { (error, ref) in
                    guard let _error = error else { return }
                    debugPrint(_error.localizedDescription)
                })

                userSearchLocationRef.onDisconnectUpdateChildValues(disconnectParameters, withCompletionBlock: { (error, ref) in
                    guard let _error = error else { return }
                    debugPrint(_error.localizedDescription)
                })
            }
        }
    }

来自 FirebaseAuthManager 的注销功能

  func logOut(completion: (() -> Void)?) {
        DispatchQueue.main.async {
            do {
                let pushNotificationManager = PushNotificationManager()
                pushNotificationManager.unregisterPushNotification()
                pushNotificationManager.removeTokenWhenLogOut(success: nil)
                // Observers
                FIRFriendsDatabaseManager.shared.observeNewFriend(false, success: nil, fail: nil)
                FIRFriendsDatabaseManager.shared.observeFriendRemoved(false, success: nil, fail: nil)
                let firChatCardManager = FIRChatCardManager()
                firChatCardManager.syncChatCardModels(false)

                FacebookManager.logOut()
                Database.database().reference().removeAllObservers()

                let firebaseGeneralDatabaseManager = FirebaseDatabaseGeneralManager()
                firebaseGeneralDatabaseManager.logOut()
                try Auth.auth().signOut()
                let realmManager = RealmManager()
                realmManager.logOut()
                let appManager = AppManager()
                appManager.logOut(isDeleteAccount: false, completion: completion)
            } catch {
                debugPrint(error.localizedDescription)
            }
        }
    }

最佳答案

我做了一个计算连接设备数量的云函数，如果连接设备数量为0，那么我设置值isOnline = false并设置lastSeenTimeStamp

const functions = require('firebase-functions');
const admin = require('firebase-admin');

module.exports = functions.database.ref('userOnlineDevices/{userID}/{onlineSystemModelID}')
    .onWrite(event => {

        const snapshot = event.data;
        const userID = event.params.userID;
        const onlineSystemModelID = event.params.onlineSystemModelID;

        const currentData = event.data.current;
        const previousData = event.data.previous;

        console.log("currentData.val()", currentData.val(), "previousData.val()", previousData.val());

        if (currentData.val() && !previousData.val()) {
            // value created

            const checkUserRef = admin.database().ref("users").child(userID);
            const checkUserRefPromise = checkUserRef.once("value", function(checkUserRefSnap, error) {
                if (error) {
                    return console.log("created checkUserRefPromise error", error);
                }
                if (checkUserRefSnap.val()) {
                    const checkUserID = checkUserRefSnap.val()["id"];
                    if (checkUserID == null) {
                        return console.log("checkUserID == null")
                    } else {
                        console.log("checkUserID", checkUserID)
                    }

                    const recentActivityTimeStamp = Math.floor(Date.now() / 1000);
                    const userRef = admin.database().ref("users").child(userID);
                    const userRefPromise = userRef.update({
                        "isOnline": true
                    });

                    const userSearchLocationModelRef = admin.database().ref("userSearchLocationModel").child(userID);
                    const userSearchLocationModelRefPromise = userSearchLocationModelRef.update({
                        "isOnline": true,
                        "recentActivityTimeStamp": recentActivityTimeStamp
                    });

                    return Promise.all([userRefPromise, userSearchLocationModelRefPromise]);
                } else {
                    return console.log("checkUserRefSnap.val() == null")
                }
            });

            return Promise.all([checkUserRefPromise]);
        } else if (!currentData.val() && previousData.val()) {
            // value removed
            const checkUserRef = admin.database().ref("users").child(userID);
            const checkUserRefPromise = checkUserRef.once("value", function(checkUserRefSnap, error) {
                if (error) {
                    return console.log(error);
                }

                if (checkUserRefSnap.val()) {
                    const checkUserID = checkUserRefSnap.val()["id"];
                    if (checkUserID == null) {
                        return console.log("checkUserID == null")
                    } else {
                        console.log("checkUserID", checkUserID)
                    }

                    if (userID) {
                        const removedTimeStamp = new Date() / 1000;
                        const userRef = admin.database().ref("users").child(userID);
                        const userRefPromise = userRef.update({
                            "isOnline": false,
                            "lastSeenTimeStamp": removedTimeStamp
                        });

                        const userSearchLocationModelRef = admin.database().ref("userSearchLocationModel").child(userID);
                        const userSearchLocationModelRefPromise = userSearchLocationModelRef.update({
                            "isOnline": false,
                            "lastSeenTimeStamp": removedTimeStamp
                        });

                        return Promise.all([userRefPromise, userSearchLocationModelRefPromise]);
                    } else {
                        return console.log("removed, userID == null");
                    }
                } else {
                    return console.log("removed, checkUserRefSnap.val() == null");
                }
            });

           return Promise.all([checkUserRefPromise]);
        } else {
            // updated
            const checkUserRef = admin.database().ref("users").child(userID);
            const checkUserRefPromise = checkUserRef.once("value", function(checkUserRefSnap, error) {
                if (error) {
                    return console.log(error);
                }

                if (checkUserRefSnap.val()) {
                    const checkUserID = checkUserRefSnap.val()["id"];
                    if (checkUserID == null) {
                        return console.log("checkUserID == null")
                    } else {
                        console.log("checkUserID", checkUserID)
                    }

                    const recentActivityTimeStamp = Math.floor(Date.now() / 1000);
                    const userRef = admin.database().ref("users").child(userID);
                    const userRefPromise = userRef.update({
                        "isOnline": true
                    });

                    const userSearchLocationModelRef = admin.database().ref("userSearchLocationModel").child(userID);
                    const userSearchLocationModelRefPromise = userSearchLocationModelRef.update({
                        "isOnline": true,
                        "recentActivityTimeStamp": recentActivityTimeStamp
                    });

                    return Promise.all([userRefPromise, userSearchLocationModelRefPromise]);
                } else {
                    return console.log("updated checkUserRefSnap.val() == null");
                }
            });

            return Promise.all([checkUserRefPromise]);
        }
    });

关于ios - iOS 上的 Firebase 离线功能，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/44472968/