当服务器发布消息的时候，会进入此函数，对数据进行解析数据，数据格式为json格式，如代码所示。
u8 MQTT_Publish(unsigned char* data,int len)
{
int buflen = sizeof(buf);
int rc = 0;
unsigned char dup;
int qos;
unsigned char retained = 0;
unsigned short msgid = 1;
int payloadlen_in;
unsigned char* payload_in;
MQTTString receivedTopic;
cJSON *json , *json_params, *json_id, *json_led, *json_display;
memcpy(buf,data,len);
rc = MQTTDeserialize_publish(&dup, &qos, &retained, &msgid, &receivedTopic,&payload_in, &payloadlen_in, (unsigned char*)buf, buflen); //服务器有推送信息
printf("message arrived : %s\r\n", payload_in);
json = cJSON_Parse((char *)payload_in); //解析数据包
if (!json)
{
printf("Error before: [%s]\r\n",cJSON_GetErrorPtr());
}
else
{
json_id = cJSON_GetObjectItem(json , "id");
if(json_id->type == cJSON_String)
{
printf("id:%s\r\n", json_id->valuestring);
}
json_params = cJSON_GetObjectItem(json , "params");
if(json_params)
{
if(cJSON_GetObjectItem(json_params, "LED0"))
{
json_led = cJSON_GetObjectItem(json_params, "LED0");
if(json_led->type == cJSON_Number)
{
printf("LED:%d\r\n", json_led->valueint);
if(json_led->valueint == 1)
{
LED0 = 0;
}
else
{
LED0 = 1;
}
}
}
if(cJSON_GetObjectItem(json_params, "display"))
{
json_display = cJSON_GetObjectItem(json_params, "display");
if (json_display->type == cJSON_String)
{
//暂不处理
}
}
}
}
cJSON_Delete(json);
return TRUE;
}
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