我创建了一个使用swift发布和订阅实时消息的示例iOS应用程序，使用了Pubnub SDK。发布设备还订阅了发布渠道。我正面临一些延迟问题（大约1.5秒），以便在订阅者回调上获取已发布的消息。此延迟仅在两种情况下发生。
这两种情况我都有1.5秒的延迟。 但是，如果我不断发布消息，则没有延迟问题，我的延迟时间仅为0.2秒。
我正在使用Pubnub SDK版本 - 4.7.2，并在运行版本为9及更高版本的iOS设备上运行。
在印度和澳大利亚进行测试时遇到了这个问题，我没有机会在其他国家进行测试。
我正在使用pubnub客户端附加我的代码，以及我如何发布消息和订阅频道。
fileprivate let publishKey = "pub-c-2ca0-redacted"
fileprivate let subscribeKey = "sub-c-91bd-redacted"
extension Date {
static var formatter: DateFormatter = {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm:ss.SSSSz"
return dateFormatter
} ()
var stringFormat: String {
return Date.formatter.string(from: self)
}
}
class ViewController: UIViewController {
@IBOutlet weak var textField: UITextField!
@IBOutlet weak var label: UILabel!
var client : PubNub?
let publishQueue = DispatchQueue(label: "Publish Queue", qos: .userInitiated, attributes: [.concurrent])
let callbackQueue = DispatchQueue(label: "PubNubCallbackQueue", qos: .userInitiated, attributes: [.concurrent])
@IBAction func publish(_ sender: Any) {
// We NEED to get the text field contents in the main thread or we violate UIKit API
let publishStep0 = Date()
DispatchQueue.main.async {
let publishStep1 = Date()
let publishText = self.textField.text ?? "default"
self.publishQueue.async {
let publishStep2 = Date()
self.client?.publish(publishText, toChannel: "my_channel1",
compressed: false, withCompletion: { (status) in
let publishStep3 = Date()
print("****** \(#function) publish steps ******")
print("Step 1: \(#function) => Tap Button: \(publishStep0.stringFormat)")
print("Step 1: \(#function) => Get Text from TextField \(publishStep1.stringFormat)")
print("Step 2: \(#function) => Initiate Publish \(publishStep2.stringFormat)")
print("Step 3: \(#function) => Receive Publish Callback \(publishStep3.stringFormat)")
print("****************************************")
if !status.isError {
}
else{
}
})
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
let config = PNConfiguration(publishKey: publishKey, subscribeKey: subscribeKey)
config.stripMobilePayload = false
self.client = PubNub.clientWithConfiguration(config, callbackQueue: callbackQueue)
self.client?.logger.enabled = true
self.client?.logger.setLogLevel(PNLogLevel.PNVerboseLogLevel.rawValue)
// optionally add the app delegate as a listener, or anything else
// View Controllers should get the client from the App Delegate
// and add themselves as listeners if they are interested in
// stream events (subscribe, presence, status)
self.client?.addListener(self)
self.client?.subscribeToChannels(["my_channel1"], withPresence: false)
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
// MARK: - PNObjectEventListener
extension ViewController: PNObjectEventListener {
func client(_ client: PubNub, didReceive status: PNStatus) {
print("Status \(status.stringifiedCategory()) at time: \(Date().stringFormat)")
}
func client(_ client: PubNub, didReceiveMessage message: PNMessageResult) {
DispatchQueue.main.async {
print("$$$$$$$$$$$$$$$$ Message received $$$$$$$$$$$$$$$$")
print("message: \(message.debugDescription)")
print("time: \(Date().stringFormat)")
print("$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$")
// self.label.text = self.label.text?.appending(",\(message.data.message!) ") // this is bad because there might not initially be text, what is the behavior of appending when the label has no text?
let currentText = self.label.text ?? ""
let appendingText = message.data.message ?? "No text in message"
self.label.text = currentText.appending(",\(appendingText)")
self.label.setNeedsLayout() // don't forget to tell the view engine to update the label
}
}
func client(_ client: PubNub, didReceivePresenceEvent event: PNPresenceEventResult) {
// This most likely won't be used here, but in any relevant view controllers
}
}