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UDP连接Swift问题

发布时间:2022-08-09 23:45:56 319
# swift# 服务器# 数据# 服务器

我试图在Swift中使用UDP连接到外部硬件,但当我尝试发送数据时,它只将数据发送到IP255.255.255.255192.168.4.1.

使用Wireshark检查数据包,它仅在IP为255.255.255.255这是行不通的,因为服务器没有收到。

服务器工作正常,因为我将其与C代码一起使用,没有任何问题。

import Foundation
import Network
import Combine

class UDPListener: ObservableObject {
    
    var listener: NWListener?
    var connection: NWConnection?
    var queue = DispatchQueue.global(qos: .userInitiated)
    /// New data will be place in this variable to be received by observers
    @Published private(set) public var messageReceived: Data?
    /// When there is an active listening NWConnection this will be `true`
    @Published private(set) public var isReady: Bool = false
    /// Default value `true`, this will become false if the UDPListener ceases listening for any reason
    @Published public var listening: Bool = true
    
    /// A convenience init using Int instead of NWEndpoint.Port
    convenience init(on port: Int) {
        self.init(on: NWEndpoint.Port(integerLiteral: NWEndpoint.Port.IntegerLiteralType(port)))
    }
    /// Use this init or the one that takes an Int to start the listener
    init(on port: NWEndpoint.Port) {
        let params = NWParameters.udp
        params.allowFastOpen = true
        params.allowLocalEndpointReuse = true
        self.listener = try? NWListener(using: params, on: port)
        self.listener?.stateUpdateHandler = { update in
            switch update {
            case .ready:
                self.isReady = true
                print("Listener connected to port \(port)")
            case .failed, .cancelled:
                // Announce we are no longer able to listen
                self.listening = false
                self.isReady = false
                print("Listener disconnected from port \(port)")
            default:
                print("Listener connecting to port \(port)...")
            }
        }
        self.listener?.newConnectionHandler = { connection in
            print("Listener receiving new message")
            self.createConnection(connection: connection)
        }
        self.listener?.start(queue: self.queue)
    }
    
    func createConnection(connection: NWConnection) {
        self.connection = connection
        self.connection?.stateUpdateHandler = { (newState) in
            switch (newState) {
            case .ready:
                print("Listener ready to receive message - \(connection)")
                self.receive()
            case .cancelled, .failed:
                print("Listener failed to receive message - \(connection)")
                // Cancel the listener, something went wrong
                self.listener?.cancel()
                // Announce we are no longer able to listen
                self.listening = false
            default:
                print("Listener waiting to receive message - \(connection)")
            }
        }
        self.connection?.start(queue: .global())
    }
    
    func receive() {
        self.connection?.receiveMessage { data, context, isComplete, error in
            if let unwrappedError = error {
                print("Error: NWError received in \(#function) - \(unwrappedError)")
                return
            }
            guard isComplete, let data = data else {
                print("Error: Received nil Data with context - \(String(describing: context))")
                return
            }
            self.messageReceived = data
            if self.listening {
                self.receive()
            }
        }
    }
    
    func cancel() {
        self.listening = false
        self.connection?.cancel()
    }
}

和SwiftUI:

//
//  ContentView.swift
//  Shared
//
//  Created by Sebas Bejenaru on 18/7/22.
//

import SwiftUI
import Network

struct ContentView: View {
    
    @State var connection: NWConnection?
        
    var host: NWEndpoint.Host = "255.255.255.255"
    var port: NWEndpoint.Port = 8080
    
    var body: some View {
        VStack {
            Spacer()
            Button("Setup") {
                NSLog("Connect pressed")
                setup()
            }
            Spacer()
            Button("Connect") {
                NSLog("Connect pressed")
                connect()
            }
            Spacer()
            Button("Send") {
                NSLog("Send pressed")
                send("S".data(using: .utf8)!)
            }
            Spacer()
        }.padding()
    }
    
    func setup() {
        let listener = UDPListener(on: 8080)
        let udpListener = NWParameters.udp
        udpListener.allowLocalEndpointReuse = true
        
        let connection = NWConnection(host: host, port: port, using: udpListener)
        listener.createConnection(connection: connection)
        listener.connection?.send(content: ("S".data(using: .utf8)!), completion: .contentProcessed({ sendError in
            if let error = sendError {
                NSLog("Unable to process and send the data: \(error)")
            } else {
                NSLog("Data has been sent")
                listener.connection!.receiveMessage { (data, context, isComplete, error) in
                    guard let myData = data else { return }
                    print("received data")
                    print(myData)
                }
            }
        }))
        listener.receive()
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}
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