我像在 Firebase 事件数据库中一样实现了该系统。点赞计数器位于 EventModel -> likesInfo -> likesNumber 处。问题在于数据发散，例如，如果两个用户快速(0.5秒)喜欢/不喜欢(反之亦然)，那么可能在测试完成后，两个用户都停止在不喜欢上，likesNumber将为1 (错误)有时差异可能是 4-6 个值。一开始我是用runTransactionBlock实现到应用程序中的，后来我想通过事件中感兴趣的用户数量来统计，并使用云函数来实现这一点，但结果更糟糕比应用程序中的内容要多。我见过一些示例，包括 firebase 示例(其中 one)，但其中一些示例不适合，因为如果事件有很多数据，则有必要在事件模型中存储大量数据。喜欢。其他的我也用过，但没有什么效果。我附上下面的代码。请告诉我如何最好地实现这个系统？
来自应用程序的代码
private func likeNumber(_ eventID: String, isLike: Bool, success: ((_ isCommited: Bool) -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
let eventRef = Database.database().reference().child(self.MainPath.events.rawValue).child(eventID).child(self.SubPath.likesInfo.rawValue).child(self.SubPath.likesNumber.rawValue)
eventRef.runTransactionBlock({ (currentData) -> TransactionResult in
var likesNumber = currentData.value as? Int ?? 0
debugPrint("likesNumber", likesNumber)
if isLike {
likesNumber += 1
} else {
likesNumber -= 1
}
if likesNumber < 0 {
likesNumber = 0
}
debugPrint("sumarry likesNumber", likesNumber)
currentData.value = likesNumber
return TransactionResult.success(withValue: currentData)
}, andCompletionBlock: { (error, commited, snap) in
if let _error = error {
debugPrint("_error", _error.localizedDescription)
fail?(_error)
return
}
if commited {
debugPrint("commited", commited)
}
success?(commited)
debugPrint("snap", snap?.value ?? "")
})
}
}
云功能
var functions = require('firebase-functions');
var eventManager = require('../Managers/event-manager');
module.exports = functions.database.ref('eventLikedUsers/{eventID}/{userID}').onDelete(event => {
const eventID = event.params.eventID;
return eventManager.incrementLikesNumber(eventID, false);
});
module.exports = functions.database.ref('eventLikedUsers/{eventID}/{userID}').onCreate(event => {
const eventID = event.params.eventID;
return eventManager.incrementLikesNumber(eventID, true);
});
来自EventManager的代码
exports.incrementLikesNumber = function incrementLikesNumber(eventID, isLike) {
return new Promise((resolve, reject) => {
const eventRef = admin.database().ref()
.child('events')
.child(eventID)
.child('likesInfo')
.child('likesNumber');
const prom = eventRef.transaction(currentData => {
if (isLike) {
return (currentData || 0) + 1;
} else {
return (currentData || 1) - 1;
}
});
return prom
.then(() => {
return resolve('success operation')
}).catch(error => {
return reject(error)
})
});
};
最佳答案
我在 EventsLikeManager 中为一个事件的喜欢/不喜欢函数创建了一个队列。例如，如果为事件 id 1 执行某个功能，并且请求为事件 id 1 执行相同的功能，则第二个请求将排队并等待第一个请求被执行。代码没有重构，完全可以工作，通过了测试。
class EventsLikeManager {
// MARK: - Init
private init() { }
static let shared = EventsLikeManager()
private let MainPath = EventsPaths.MainPath.self
private let SubPath = EventsPaths.SubPath.self
private let systemQueue = DispatchQueue(label: "com.myapp.EventsLikeManager.systemQueue")
// id, time,
private var dict = [String : [EventSystemLikeDislikeModel]]()
// MARK: - Like actions
func likeEvents(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
guard newSystemEvent(event) else { return }
_likeEvents(event, success: success, fail: fail)
}
private func _likeEvents(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
FirebasePerformanceManager.shared.likeDislikeAction(true)
DispatchQueue.global(qos: .background).async {
if event.systemInfo.sourceIndex == EventSystemModel.Source.firebase.index {
self.eventLikeInternalSourceAction(event, success: success, fail: fail)
} else {
self.eventLikeOutsourceAction(event, success: success, fail: fail)
}
}
}
private func eventLikeOutsourceAction(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
Auth.auth().currentUser?.getIDTokenForcingRefresh(true, completion: { (token, error) in
guard token != nil else { return }
let timestamp = Date().currentTimestamp
event.systemTimeProperties.creationTimestamp = timestamp
event.systemTimeProperties.updateTimestamp = timestamp
event.systemInfo.sourceIndex = EventSystemModel.Source.firebase.index
self.createEvent(event, success: {
self.userLikedEvent(event.id, notExists: { self.likeAction(event, timestamp: timestamp, success: success, fail: fail)
}, success: { (likeModel) in
// dislike
self.dislikeAction(event, success: success, fail: fail)
}, fail: fail)
}, fail: { (error) in
})
})
}
}
private func eventLikeInternalSourceAction(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
userLikedEvent(event.id, notExists: {
self.likeAction(event, success: success, fail: fail)
}, success: { (likeModel) in
// dislike
self.dislikeAction(event, success: success, fail: fail)
}, fail: fail)
}
func createEvent(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
let dispatchGroup = DispatchGroup()
var commonError: Error?
let eventRef = Database.database().reference().child(self.MainPath.events.rawValue).child(event.id)
dispatchGroup.enter()
eventRef.runTransactionBlock({ (currentData) -> TransactionResult in
if (currentData.value as? [String : Any]) != nil {
debugPrint("TransactionResult.abort()")
return TransactionResult.abort()
} else {
dispatchGroup.enter()
self.createEventLocation(event, success: {
dispatchGroup.leave()
}, fail: { (error) in
dispatchGroup.leave()
})
currentData.value = event.toJSON()
return TransactionResult.success(withValue: currentData)
}
}, andCompletionBlock: { (error, isCommited, snap) in
commonError = error
debugPrint("isCommited", isCommited)
dispatchGroup.leave()
})
dispatchGroup.notify(queue: .global(qos: .background), execute: {
if let error = commonError {
fail?(error)
} else {
success?()
}
})
}
}
private func createEventLocation(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
let eventLocationRef = Database.database().reference().child(self.MainPath.eventsLocations.rawValue)
guard let geofire = GeoFire(firebaseRef: eventLocationRef) else { return }
let coordinate = event.location.coordinate
let location = CLLocation(latitude: coordinate.latitude, longitude: coordinate.longitude)
geofire.setLocation(location, forKey: event.id, withCompletionBlock: { (error) in
if let _error = error {
fail?(_error)
} else {
success?()
}
})
}
}
}
// MARK: - Likes' functions
extension EventsLikeManager {
private func likeAction(_ event: EventModel, timestamp: Double? = nil, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
var finalTimestamp = Date().currentTimestamp
if let _timestamp = timestamp {
finalTimestamp = _timestamp
}
var commonError: Error?
let dispatchGroup = DispatchGroup()
dispatchGroup.enter()
self.likeNumber(event.id, isLike: true, success: { (isCommited) in
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.enter()
self.addEventToUserList(event, timestamp: finalTimestamp, success: {
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.enter()
self.addUserToEventUsersList(event.id, timestamp: finalTimestamp, success: {
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.notify(queue: .main, execute: {
self.checkSystemEventQueue(event)
if let error = commonError {
fail?(error)
} else {
success?()
}
FirebasePerformanceManager.shared.likeDislikeAction(false)
})
}
}
private func likeNumber(_ eventID: String, isLike: Bool, success: ((_ isCommited: Bool) -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
let eventRef = Database.database().reference().child(self.MainPath.events.rawValue).child(eventID).child(self.SubPath.likesInfo.rawValue).child(self.SubPath.likesNumber.rawValue)
eventRef.runTransactionBlock({ (currentData) -> TransactionResult in
var likesNumber = currentData.value as? Int ?? 0
debugPrint("likesNumber", likesNumber)
if isLike {
likesNumber += 1
} else {
likesNumber -= 1
}
if likesNumber < 0 {
likesNumber = 0
}
debugPrint("sumarry likesNumber", likesNumber)
currentData.value = likesNumber
return TransactionResult.success(withValue: currentData)
}, andCompletionBlock: { (error, commited, snap) in
if let _error = error {
debugPrint("_error", _error.localizedDescription)
fail?(_error)
return
}
if commited {
debugPrint("commited", commited)
}
success?(commited)
debugPrint("snap", snap?.value ?? "")
})
}
}
private func addEventToUserList(_ event: EventModel, timestamp: Double, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.main.async {
guard let userID = RealmManager().getCurrentUser()?.id else { return }
DispatchQueue.global(qos: .background).async {
let ref = Database.database().reference().child(self.MainPath.userLikedEvents.rawValue).child(userID).child(event.id)
let eventUserLike = EventUserLikeModel(eventID: event.id, systemInfo: event.systemInfo, dateInfo: event.dateProperties, systemTimestamp: timestamp)
let json = eventUserLike.toJSON()
ref.setValue(json, withCompletionBlock: { (error, ref) in
if let _error = error {
fail?(_error)
} else {
success?()
}
})
}
}
}
private func addUserToEventUsersList(_ eventID: String, timestamp: Double, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.main.async {
guard let userID = RealmManager().getCurrentUser()?.id else { return }
DispatchQueue.global(qos: .background).async {
let ref = Database.database().reference().child(self.MainPath.eventLikedUsers.rawValue).child(eventID).child(userID)
let json = ["userID" : userID, "timestamp" : timestamp] as [String : Any]
ref.setValue(json, withCompletionBlock: { (error, ref) in
if let _error = error {
fail?(_error)
} else {
success?()
}
})
}
}
}
}
// MARK: - Dislikes' functions
extension EventsLikeManager {
private func dislikeAction(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.global(qos: .background).async {
var commonError: Error?
let dispatchGroup = DispatchGroup()
dispatchGroup.enter()
self.likeNumber(event.id, isLike: false, success: { (isCommited) in
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.enter()
self.removeEventFromUserList(event.id, success: {
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.enter()
self.removeUserFromEventUsersList(event.id, success: {
dispatchGroup.leave()
}, fail: { (error) in
commonError = error
dispatchGroup.leave()
})
dispatchGroup.notify(queue: .main, execute: {
self.checkSystemEventQueue(event)
if let error = commonError {
fail?(error)
} else {
success?()
}
FirebasePerformanceManager.shared.likeDislikeAction(false)
})
}
}
private func removeEventFromUserList(_ eventID: String, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.main.async {
guard let currentUserID = RealmManager().getCurrentUser()?.id else { return }
DispatchQueue.global(qos: .background).async {
let ref = Database.database().reference().child(self.MainPath.userLikedEvents.rawValue).child(currentUserID).child(eventID)
ref.removeValue(completionBlock: { (error, ref) in
if let _error = error {
fail?(_error)
} else {
success?()
}
})
}
}
}
private func removeUserFromEventUsersList(_ eventID: String, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.main.async {
guard let userID = RealmManager().getCurrentUser()?.id else { return }
DispatchQueue.global(qos: .background).async {
let ref = Database.database().reference().child(self.MainPath.eventLikedUsers.rawValue).child(eventID).child(userID)
ref.removeValue(completionBlock: { (error, ref) in
if let _error = error {
fail?(_error)
} else {
success?()
}
})
}
}
}
}
// MARK: - Check events
extension EventsLikeManager {
private func userLikedEvent(_ eventID: String, notExists: (() -> Void)?, success: ((_ userLike: EventUserLikeModel) -> Void)?, fail: ((_ error: Error) -> Void)?) {
DispatchQueue.main.async {
guard let currentUserID = RealmManager().getCurrentUser()?.id else { return }
DispatchQueue.global(qos: .background).async {
let userLikedEventRef = Database.database().reference().child(self.MainPath.userLikedEvents.rawValue).child(currentUserID).child(eventID)
userLikedEventRef.observeSingleEvent(of: .value, with: { (snap) in
guard snap.exists() else {
notExists?()
return
}
guard let json = snap.value as? [String : Any] else { return }
guard let likedEvent = Mapper<EventUserLikeModel>().map(JSON: json) else { return }
success?(likedEvent)
}, withCancel: { (error) in
fail?(error)
})
}
}
}
}
// MARK: - Like Actions Helpers
extension EventsLikeManager {
private func getEventbriteAdditionalInfo(_ event: EventModel, success: (() -> Void)?, fail: ((_ error: Error) -> Void)?) {
let eventbriteAPIManager = EventbriteAPIManager()
eventbriteAPIManager.getAdditionalInfo(event, success: { (updatedEvent) in
self.eventLikeOutsourceAction(updatedEvent, success: success, fail: fail)
}, fail: fail)
}
}
// MARK: - System
extension EventsLikeManager {
private func newSystemEvent(_ event: EventModel) -> Bool {
let timestamp = Date().currentTimestamp
if dict[event.id] == nil {
dict[event.id] = [EventSystemLikeDislikeModel(timestamp: timestamp)]
} else if dict[event.id]?.count == 0 {
dict[event.id] = [EventSystemLikeDislikeModel(timestamp: timestamp)]
} else if var systemEvents = dict[event.id], systemEvents.count > 0 {
debugPrint("systemEvents", systemEvents.count)
let systemEvent = EventSystemLikeDislikeModel(timestamp: timestamp)
systemEvents.append(systemEvent)
dict[event.id] = systemEvents
return false
}
return true
}
private func checkSystemEventQueue(_ event: EventModel) {
systemQueue.sync {
guard var array = dict[event.id] else { return }
guard array.first != nil else { return }
array.removeFirst()
debugPrint("checkSystemEventQueue array.count", array.count)
if array.count > 0 {
dict[event.id] = array
} else {
dict[event.id] = nil
return
}
_likeEvents(event, success: nil, fail: nil)
}
}
}
关于ios - Firebase 喜欢/不喜欢系统，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/47792315/