Swift SimplePing 不起作用

Question

I'm using SimplePing to get the latency in my swift application but I don't get any result.

This is the code taken form an example here in SO:

import Foundation

public typealias SimplePingClientCallback = (String?)->()

public class SimplePingClient: NSObject {
    static let singletonPC = SimplePingClient()

    private var resultCallback: SimplePingClientCallback?
    private var pingClinet: SimplePing?
    private var dateReference: NSDate?

    public static func pingHostname(hostname: String, andResultCallback callback: SimplePingClientCallback?) {
        singletonPC.pingHostname(hostname, andResultCallback: callback)
    }

    public func pingHostname(hostname: String, andResultCallback callback: SimplePingClientCallback?) {
        resultCallback = callback
        pingClinet = SimplePing(hostName: hostname)
        pingClinet?.delegate = self
        pingClinet?.start()
    }
}

extension SimplePingClient: SimplePingDelegate {
    public func simplePing(pinger: SimplePing, didStartWithAddress address: NSData) {
        pinger.sendPingWithData(nil)
    }

    public func simplePing(pinger: SimplePing, didFailWithError error: NSError) {
        resultCallback?(nil)
    }

    public func simplePing(pinger: SimplePing!, didSendPacket packet: NSData!) {
        dateReference = NSDate()
    }

    public func simplePing(pinger: SimplePing!, didFailToSendPacket packet: NSData!, error: NSError!) {
        pinger.stop()
        resultCallback?(nil)
    }

    public func simplePing(pinger: SimplePing, didReceiveUnexpectedPacket packet: NSData) {
        pinger.stop()
        resultCallback?(nil)
    }

    public func simplePing(pinger: SimplePing!, didReceivePingResponsePacket packet: NSData!) {
        pinger.stop()

        guard let dateReference = dateReference else { return }

        //timeIntervalSinceDate returns seconds, so we convert to milis
        let latency = NSDate().timeIntervalSinceDate(dateReference) * 1000

        resultCallback?(String(format: "%.f", latency))
    }
}

And to call the SimplePing in my viewController I do that:

let simplePingClient = SimplePingClient()
        simplePingClient.pingHostname("www.apple.com") { latency in
        print("Your latency is \(latency ?? "unknown")")
        self.labelTempsReponse?.text = latency
        }

When I put a breakpoint at this line:

simplePingClient.pingHostname("www.apple.com") { latency in

all the results are nil (the resultCallBack, the pingClient and the dateReference). I made a research to solve this issue and I found a question similar to mine but in objective c.

Can anyone help me please?

Answer 1

The signatures in SimplePingClient don't match the SimplePingDelegate protocol it is trying to implement. Perhaps these once matched in some earlier version, but as of Swift 5/XCode 12.2 and using Apple's SimplePing code last updated 2016 they don't. Some datatypes are wrong, some parameter labels mismatched, and some parameters missing. This means SimplePingClient never gets its callbacks because SimplePing looks for a matching signature in the delegate object, finds none, and skips the callback.

Further, because SimplePing.h declares these delegate methods as optional you get no compiler errors.

To see the errors, and to get XCode to offer to write protocol stubs for you, comment out the @optional in the SimplePingDelegate definition in SimplePing.h (line 142).

Here are the changes to the SimplePingClient class extension I needed to make to get SimplePingClient to work:

extension SimplePingClient: SimplePingDelegate {
    
    public func simplePing(_ pinger: SimplePing, didStartWithAddress address: Data) {
        pinger.send(with: nil)
    }

    public func simplePing(_ pinger: SimplePing, didFailWithError error: Error) {
        resultCallback?(nil)
    }

    public func simplePing(_ pinger: SimplePing, didSendPacket packet: Data, sequenceNumber:UInt16) {
        dateReference = Date()
    }

    public func simplePing(_ pinger: SimplePing, didFailToSendPacket packet: Data, sequenceNumber: UInt16, error: Error) {
        pinger.stop()
        resultCallback?(nil)
    }

    public func simplePing(_ pinger: SimplePing, didReceiveUnexpectedPacket packet: Data) {
        pinger.stop()
        resultCallback?(nil)
    }

    public func simplePing(_ pinger: SimplePing, didReceivePingResponsePacket packet: Data, sequenceNumber:UInt16) {
        pinger.stop()

        guard let dateReference = dateReference else { return }

        //timeIntervalSinceDate returns seconds, so we convert to milis
        let latency = Date().timeIntervalSince(dateReference ) * 1000

        resultCallback?(String(format: "%.f", latency))
    }
}

Answer 2

could it be the case that simplePingClient is going out of scope ? In this case, the simplePing will shutdown. Try to declare as a global variable:

var simplePingClient : SimplePingClient!

and then this should work:

simplePingClient = SimplePingClient()
    simplePingClient.pingHostname("www.apple.com") { latency in
    print("Your latency is \(latency ?? "unknown")")
    self.labelTempsReponse?.text = latency
    }