iOS —— CocoaAsyncSocket

CocoaAsyncSocket为macOS、iOS和tvOS提供了易于使用且功能强大的异步套接字库。他是基于C 语言Socket的一层封装，更加的面向对象。使得原生连接状态以及接受消息等函数都以代理的方式体现。使用性极高，极大提高开发效率。

CocoaAsyncSocket中主要包含两个类:

• GCDAsyncSocket.//基于TCP/IP协议的socket网络库
• GCDAsyncUdpSocket.//基于UDP/IP协议的socket网络库

GCDAsyncSocket 的使用

@property (nonatomic, strong) GCDAsyncSocket *socket;

    // 1: 创建socekt --id -->
    if (self.socket == nil) {
        self.socket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_global_queue(0, 0)];
    }
    
    // 2: 连接socket
    if (!self.socket.isConnected) {
        NSError *error;
        [self.socket connectToHost:@"127.0.0.1" onPort:8090 error:&error];
    }

  // 发送消息
     NSData *data = [self.contentTF.text dataUsingEncoding:NSUTF8StringEncoding];
    [self.socket writeData:data withTimeout:-1 tag:10086];

   GCDAsyncSocketDelegate

//已经连接到服务器
- (void)socket:(GCDAsyncSocket *)sock didConnectToHost:(nonnull NSString *)host port:(uint16_t)port{
    
    NSLog(@"连接成功 : %@---%d",host,port);
    [self.socket readDataWithTimeout:-1 tag:10086];
}

// 连接断开
- (void)socketDidDisconnect:(GCDAsyncSocket *)sock withError:(NSError *)err{
    NSLog(@"断开 socket连接 原因:%@",err);
}

//已经接收服务器返回来的数据
- (void)socket:(GCDAsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag{
    NSLog(@"接收到tag = %ld : %ld 长度的数据",tag,data.length);
    [self.socket readDataWithTimeout:-1 tag:10086];
   // 每次发送数据必须重新开启监听，（经典问题）
}

//消息发送成功 代理函数 向服务器 发送消息
- (void)socket:(GCDAsyncSocket *)sock didWriteDataWithTag:(long)tag{
    NSLog(@"%ld 发送数据成功",tag);
}

重连和断开的操作

//重新连接
    // 1: 创建socekt --id -->
    if (self.socket == nil) {
        self.socket = [[GCDAsyncSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_global_queue(0, 0)];
    }
    
    // 2: 连接socket
    if (!self.socket.isConnected) {
        NSError *error;
        [self.socket connectToHost:@"127.0.0.1" onPort:8090 error:&error];
    }

//关闭socket
    [self.socket disconnect];
    self.socket = nil;

GCDAsyncUdpSocket

udp 在连接的时候直接绑定端口，不需要地址的连接，极大节约了时间。 在发送消息的时候，直接对着某个地址的的某个端口直接发送，类似广播形式。

@property (nonatomic, strong) GCDAsyncUdpSocket *udpSocket;

 // 1. 创建UDP
    if (!self.udpSocket) {
        self.udpSocket = [[GCDAsyncUdpSocket alloc]initWithDelegate:sender delegateQueue:dispatch_get_global_queue(0, 0)];
    }
    //2. 绑定socket
    NSError *error;
    [self.udpSocket bindToPort:8090 error:&error];
    if (error) {
        // 监听错误
    }else{
        //监听成功则开始接收消息
        [self.udpSocket beginReceiving:&error];
    }
   // 发送消息
    [self.udpSocket sendData:[NSData new] toHost:@"192.168.31.19" port:8090 withTimeout:-1 tag:10010];


#pragma mark - GCDAsyncUdpSocketDelegate

// 连接成功
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didConnectToAddress:(NSData *)address{
    NSLog(@"连接成功 --- %@",address);
}

// 连接失败
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didNotConnect:(NSError *)error{
    NSLog(@"连接失败 反馈: %@",error);
}

// 发送数据成功
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didSendDataWithTag:(long)tag{
    NSLog(@"%ld tag 发送数据成功",tag);
}

// 发送数据失败
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didNotSendDataWithTag:(long)tag dueToError:(NSError *)error{
    NSLog(@"%ld tag 发送数据失败 : %@",tag,error);
}

// 接受数据的回调
- (void)udpSocket:(GCDAsyncUdpSocket *)sock didReceiveData:(NSData *)data fromAddress:(NSData *)address withFilterContext:(id)filterContext{
    
}

// 关闭失败
- (void)udpSocketDidClose:(GCDAsyncUdpSocket *)sock withError:(NSError *)error{
    NSLog(@"关闭失败: %@",error);
}