W5100S_EVB_PICO快速入门之MQTT篇（十二）

4.2 相关代码

        我们打开例程中库文件的mqttx_client.c文件用到几个函数和定义：

        1.首先我们是对收发缓存大小和收发缓存数组进行定义

        2.然后创建一个 MQTTCONNECTION结构体，里面的参数有mqttHostUrl服务器网址，port端口号，clientid客户端id，username用户名，password密码，server_ip服务器ip，pubtopic发布主题，subtopic1订阅主题，QOS发布服务质量等级。

        3.接下就是定义了一个mqtt_params结构体，将结构体的参数填写进去，其中mqttHostUrl服务器网址和server_ip服务器ip填写其中一个就可以，端口固定为1883，clientid客户端id，clientid客户端id不能与同一个服务器下的clientid客户端id重名，username用户名，password密码可以任意填，也可以选择不填，订阅和发布根据自己来定，保证与另一端客户端进行通信并且不受到别人干扰。服务质量等级也是根据自己的需求来定，这里定义的是0，消息最多传送一次。如果当前客户端不可用，它将丢失这条消息

#define SOCKET_ID 0
#define ETHERNET_BUF_MAX_SIZE (1024 * 2)#define MQTT_SEND_BUFF_SIZE 2048
#define MQTT_RECV_BUFF_SIZE 2048
uint8_t mqtt_send_buff[MQTT_SEND_BUFF_SIZE] = {0};
uint8_t mqtt_recv_buff[MQTT_RECV_BUFF_SIZE] = {0};
typedef struct MQTTCONNECTION
{char mqttHostUrl[1024];int port;char clientid[1024];char username[1024];char passwd[1024];uint8_t server_ip[4];char pubtopic[255];char subtopic1[255];int QOS;
} mqttconn;
mqttconn mqtt_params = {.server_ip = {54,244,173,190},.port = 1883,.clientid = "9a1d7719a8ac40d29311f26c5c5469dc",.username = "mqtt_username",.passwd = "123456",.pubtopic = "1234",.subtopic1 = "2345",.QOS = 0,
};

void network_init(void);
wiz_NetInfo net_info = {.mac = {0x00, 0x08, 0xdc, 0x16, 0xed, 0x2e},.ip = {192, 168, 124, 10},.sn = {255, 255, 255, 0},.gw = {192, 168, 124, 1},.dns = {8, 8, 8, 8},.dhcp = NETINFO_STATIC};
MQTTClient c = {0};  

void mqtt_init(void)
{NewNetwork(&n, 1);                                                /*Obtain network configuration information*/ConnectNetwork(&n, mqtt_params.server_ip, 1883);                  /*Connect to the MQTT server*/MQTTClientInit(&c, &n, 1000, mqtt_send_buff, MQTT_SEND_BUFF_SIZE, mqtt_recv_buff, MQTT_RECV_BUFF_SIZE);data.willFlag = 0;data.MQTTVersion = 4;data.clientID.cstring = mqtt_params.clientid;data.username.cstring = mqtt_params.username;data.password.cstring = mqtt_params.passwd;data.keepAliveInterval = 30;data.cleansession = 1;sleep_ms(300);}