解析云-LiveQueries-iOS客户端不起作用 [英] Parse Cloud - LiveQueries - iOS Client doesn't work

问题描述

我正在尝试使用Parse LiveQueries. 我使用此Parse"Bootstrap":" https://github.com/parse-community/parse-服务器"，
我可以看到日志:info: Create new client: 1，
但尽管我已订阅，但我只是未在查询中得到更新.它甚至没有到达subscription.handle的处理程序.

I'm trying to use Parse LiveQueries. I use this Parse "Bootstrap": "https://github.com/parse-community/parse-server",
I can see the logs: info: Create new client: 1,
but I just do not get the update in the query although I have subscribed it. It doesn't even reach the handler of the subscription.handle.

config.json:

{
  "appId": "",
  "masterKey": "",
  "appName": "",
  "cloud": "./cloud/main",
  "databaseURI": "",
  "publicServerURL": "",    

  // Relevant
  "startLiveQueryServer": true,
  "liveQuery": {
    "classNames": ["Channel"]
  },
}

AppDelegate.swift:

// Initialize Parse.
let configuration = ParseClientConfiguration {
    $0.applicationId = self.PARSE_APP_ID
    $0.server = self.PARSE_SERVER
}
Parse.initialize(with: configuration)

AppDelegate.liveQueryClient = ParseLiveQuery.Client()

The Subscription Code(iOS Swift):

The Subscription Code (iOS Swift):

public static func listenSubscribedChannels(handler: @escaping (_ channel: Channel) -> Void) {
    var subscription: Subscription<PFObject>?

    let query: PFQuery<PFObject> = PFQuery(className: "Channel").whereKey("subscribers", containedIn: [PFUser.current()!.objectId])

    subscription = AppDelegate.liveQueryClient!.subscribe(query).handle(Event.updated) { _, channel in
        handler(channel)
    }
}

推荐答案

此代码的问题是您将此代码var subscription: Subscription<PFObject>?放置在函数内部.

The problem with this code is that you are placing this code var subscription: Subscription<PFObject>? inside the function.

该对象必须能够保留其内存地址才能接收事件.

This object must be able to retain it's memory address in order for it to receive events.

例如.

class SomeClass {
    var objects: [PFObject] = []
    var subscription: Subscription<PFObject>?
    var subscriber: ParseLiveQuery.Client!
    let query = PFQuery(className: "Locations")

    func startListener() {
        // initialize the client
        subscriber = ParseLiveQuery.Client()

        // initialize subscriber and start subscription
        subscription = subscriber.subscribe(conversationQuery)

        // handle the event listenrs.
        _ = subscription?.handleEvent({ (_, event) in
            switch event {
            case .created(let object): 
                self.objects.append(object)
                // do stuff 

            default: 
                break // do other stuff or do nothing
            }
        })
    }
}

从这段代码中可以看到，我将变量放置在函数定义之外，以便保留Subscription的内存地址.

As you can see from this code, I've placed the variables outside the function definition in order for the Subscription's memory address to be retained.

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