Swift udp实现根据端口号监听广播数据（利用GCDAsyncUdpSocket实现）

有个小需求，app需要监听pc广播的数据：

代码实现思路：

使用三方库：CocoaAsyncSocket

1、开启udp监听：

udpSocket.beginReceiving()

2、读取udp的数据，包括对方设备的ip

func udpSocket(_ sock: GCDAsyncUdpSocket, didReceive data: Data, fromAddress address: Data, withFilterContext filterContext: Any?)

实现参考代码：

1、申明变量

var udpSocket : GCDAsyncUdpSocket!

2、根据port端口开启监听

udpSocket = GCDAsyncUdpSocket(delegate: self, delegateQueue: DispatchQueue.main)
        do{
            try udpSocket.bind(toPort: )
            try udpSocket.beginReceiving()

        }catch{
            print("bind error")
        };

其中60001是定义好的端口号

3、实现代理

func udpSocket(_ sock: GCDAsyncUdpSocket, didReceive data: Data, fromAddress address: Data, withFilterContext filterContext: Any?) {
        //Optional("{\"Port\":61312,\"LPort\":61313,\"HostName\":\"Lucifer-PC\"}")"

        var hostname = [CChar].init(repeating: , count: Int(NI_MAXHOST))
        do{
            try address.withUnsafeBytes({ (pointer:UnsafePointer<sockaddr>) -> Void in
                guard getnameinfo(pointer, socklen_t(data.count), &hostname, socklen_t(hostname.count), nil, , NI_NUMERICHOST) ==  else{
                    throw NSError(domain: "domain", code: , userInfo: ["error":"unable to get ip address"])
                }
            })
        }catch(let error){
            print(error.localizedDescription)
        }
        var newAddress = String.init(cString: hostname)
        let addArry = newAddress.components(separatedBy: ":")
        if addArry.count >  {
            newAddress = addArry[addArry.count-]
        }
        print("IP:\(newAddress)")

        let dict = data.toDictionary()  //data转字典
        if let _port = dict["Port"] as? Int,let _lport = dict["LPort"] as? Int, let _name = dict["HostName"] as? String{
            //根据广播的信息，构造模型
            let model = SocketConnectModel(_ip: newAddress, _port: _port, _lport: _lport, _hostName: _name, _isconnect: false)
            addWifiArry(model: model)

        }

    }

这里解释一下：

一般情况下，我们可能只需要得到广播的内容就足够，也就是上面的 didReceive data: Data，我们直接将data转换我们需要的格式即可。

我这里比较特殊，还需要知道对方设备的ip，所以需要对 fromAddress address: Data，处理。

4、结束监听

udpSocket?.close()

退出页面，或需要结束时，记得调用close方法。

enjoy～