梅科尔-华为14天实战开发-网络应用开发（二）

TCP客户端

tcp客户端相关API介绍

tcp客户端创建流程

实现流程及代码

static void UDPClientTask(void)
{
    //服务器的地址信息
    struct sockaddr_in send_addr;
    socklen_t addr_length = sizeof(send_addr);
    char recvBuf[512];

    //连接Wifi
    WifiConnect("TP-LINK_65A8", "0987654321");

    //创建socket
    if ((sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
    {
        perror("create socket failed!\r\n");
        exit(1);
    }

    //初始化预连接的服务端地址
    send_addr.sin_family = AF_INET;
    send_addr.sin_port = htons(_PROT_);
    send_addr.sin_addr.s_addr = inet_addr("192.168.0.175");
    addr_length = sizeof(send_addr);

    //总计发送 count 次数据
    while (1)
    {
        bzero(recvBuf, sizeof(recvBuf));

        //发送数据到服务远端
        sendto(sock_fd, send_data, strlen(send_data), 0, (struct sockaddr *)&send_addr, addr_length);

        //线程休眠一段时间
        sleep(10);

        //接收服务端返回的字符串
        recvfrom(sock_fd, recvBuf, sizeof(recvBuf), 0, (struct sockaddr *)&send_addr, &addr_length);
        printf("%s:%d=>%s\n", inet_ntoa(send_addr.sin_addr), ntohs(send_addr.sin_port), recvBuf);
    }

    //关闭这个 socket
    closesocket(sock_fd);
}

UDP服务端

UDP相关协议API介绍

UDP服务端创建流程介绍

实现

static void TCPServerTask(void)
{
	//服务端地址信息
	struct sockaddr_in server_sock;

	//客户端地址信息
	struct sockaddr_in client_sock;
	int sin_size;

	struct sockaddr_in *cli_addr;

	//连接Wifi
	WifiConnect("TP-LINK_65A8", "0987654321");

	//创建socket
	if ((sock_fd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	{
		perror("socket is error\r\n");
		exit(1);
	}

	bzero(&server_sock, sizeof(server_sock));
	server_sock.sin_family = AF_INET;
	server_sock.sin_addr.s_addr = htonl(INADDR_ANY);
	server_sock.sin_port = htons(_PROT_);

	//调用bind函数绑定socket和地址
	if (bind(sock_fd, (struct sockaddr *)&server_sock, sizeof(struct sockaddr)) == -1)
	{
		perror("bind is error\r\n");
		exit(1);
	}

	//调用listen函数监听(指定port监听)
	if (listen(sock_fd, TCP_BACKLOG) == -1)
	{
		perror("listen is error\r\n");
		exit(1);
	}

	printf("start accept\n");

	//调用accept函数从队列中
	while (1)
	{
		sin_size = sizeof(struct sockaddr_in);

		if ((new_fd = accept(sock_fd, (struct sockaddr *)&client_sock, (socklen_t *)&sin_size)) == -1)
		{
			perror("accept");
			continue;
		}

		cli_addr = malloc(sizeof(struct sockaddr));

		printf("accept addr\r\n");

		if (cli_addr != NULL)
		{
			memcpy(cli_addr, &client_sock, sizeof(struct sockaddr));
		}

		//处理目标
		ssize_t ret;

		while (1)
		{
			if ((ret = recv(new_fd, recvbuf, sizeof(recvbuf), 0)) == -1)
			{
				printf("recv error \r\n");
			}
			printf("recv :%s\r\n", recvbuf);
			sleep(2);
			if ((ret = send(new_fd, buf, strlen(buf) + 1, 0)) == -1)
			{
				perror("send : ");
			}

			sleep(2);
		}

		close(new_fd);
	}
}

MQTT 客户端

MQTT介绍

嵌入式c语言客户端开源地址:
https://github.com/eclipse/paho.mqtt.embedded-c

Paho MQTT文件目录介绍

如何使用Paho MQTT

实现MQTT客户端

	NetworkConnect(&network, "192.168.0.176", 1883);
	printf("MQTTClientInit  ...\n");
	MQTTClientInit(&client, &network, 2000, sendBuf, sizeof(sendBuf), readBuf, sizeof(readBuf));

	MQTTString clientId = MQTTString_initializer;
	clientId.cstring = "bearpi";

	MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
  	data.clientID          = clientId;
	data.willFlag          = 0;
	data.MQTTVersion       = 3;
	data.keepAliveInterval = 0;
	data.cleansession      = 1;

	printf("MQTTConnect  ...\n");
	rc = MQTTConnect(&client, &data);
	if (rc != 0) {
		printf("MQTTConnect: %d\n", rc);
		NetworkDisconnect(&network);
		MQTTDisconnect(&client);
		osDelay(200);
		goto begin;
	}

	printf("MQTTSubscribe  ...\n");
	rc = MQTTSubscribe(&client, "substopic", 2, messageArrived);
	if (rc != 0) {
		printf("MQTTSubscribe: %d\n", rc);
		osDelay(200);
		goto begin;
	}
	while (++count)
	{
		MQTTMessage message;
		char payload[30];

		message.qos = 2;
		message.retained = 0;
		message.payload = payload;
		sprintf(payload, "message number %d", count);
		message.payloadlen = strlen(payload);

		if ((rc = MQTTPublish(&client, "pubtopic", &message)) != 0){
			printf("Return code from MQTT publish is %d\n", rc);
			NetworkDisconnect(&network);
			MQTTDisconnect(&client);
			goto begin;
		}
		osDelay(50);	
	}

最后