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～