MQTT如何连接阿里云订阅主题
本篇内容主要讲解“MQTT如何连接阿里云订阅主题”,感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷,实用性强。下面就让小编来带大家学习“MQTT如何连接阿里云订阅主题”吧!
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中移4G模块-ML302-OpenCpu开发-(MQTT连接阿里云-订阅主题)
模块OpenCpu部分
cm_main.c文件里面的cm_main_task是主函数,在主函数里面调用cm_test_aliyun函数。
cm_test_aliyun函数:
void cm_test_aliyun(){ cm_printf("[ALIYUN]: aliyun demo start\n"); void *pclient = NULL; int res = 0; int rpc_res = 0; int loop_cnt = 0; iotx_mqtt_param_t mqtt_params; HAL_GetProductKey(DEMO_PRODUCT_KEY); HAL_GetDeviceName(DEMO_DEVICE_NAME); HAL_GetDeviceSecret(DEMO_DEVICE_SECRET); memset(&mqtt_params, 0x0, sizeof(mqtt_params)); mqtt_params.handle_event.h_fp = example_event_handle; pclient = IOT_MQTT_Construct(&mqtt_params); if (NULL == pclient) { cm_printf("[ALIYUN]: MQTT construct failed\n"); return -1; } res = example_subscribe(pclient); //调用example_subscribe函数 if (res < 0) { IOT_MQTT_Destroy(&pclient); return -1; } while (1) { if (0 == loop_cnt % 20) { example_publish(pclient); } IOT_MQTT_Yield(pclient, 200); loop_cnt += 1; if(loop_cnt >= 100) { //break; } } cm_printf("[ALIYUN]: aliyun demo end\n"); }
example_subscribe函数:
example_subscribe一开始进行字符串连接,把${YourProductKey}/${YourDeviceName}/user/get拼接出来,然后调用IOT_MQTT_Subscribe函数订阅topic
int example_subscribe(void *handle){ int res = 0; const char *fmt = "/%s/%s/user/get"; //订阅的MQTT路径 char *topic = NULL; int topic_len = 0; topic_len = strlen(fmt) + strlen(DEMO_PRODUCT_KEY) + strlen(DEMO_DEVICE_NAME) + 1; topic = HAL_Malloc(topic_len); if (topic == NULL) { cm_printf("[ALIYUN]: memory not enough\n"); return -1; } memset(topic, 0, topic_len); HAL_Snprintf(topic, topic_len, fmt, DEMO_PRODUCT_KEY, DEMO_DEVICE_NAME); //通过HAL_Snprintf函数的拼接得出最终的MQTT路径 //示例:${YourProductKey}/${YourDeviceName}/user/get //其中的:example_message_arrive函数为接收的数据的回调函数 res = IOT_MQTT_Subscribe(handle, topic, IOTX_MQTT_QOS0, example_message_arrive, NULL); if (res < 0) { cm_printf("[ALIYUN]: subscribe failed\n"); HAL_Free(topic); return -1; } HAL_Free(topic); return 0; }
example_message_arrive函数
example_subscribe为topic接收回调函数,当接收到此topic的数据时会放到这里处理
void example_message_arrive(void *pcontext, void *pclient, iotx_mqtt_event_msg_pt msg){ iotx_mqtt_topic_info_t *topic_info = (iotx_mqtt_topic_info_pt) msg->msg; cm_printf("example_message_arrive \n"); switch (msg->event_type) { case IOTX_MQTT_EVENT_PUBLISH_RECEIVED: /* print topic name and topic message */ cm_printf("[ALIYUN]: Message Arrived:"); cm_printf("Topic : %.*s", topic_info->topic_len, topic_info->ptopic); cm_printf("Payload: %.*s", topic_info->payload_len, topic_info->payload); cm_printf("\n"); // topic_info->payload为接收到的数据 if(strcmp(topic_info->payload,"1") == 0){ cm_printf("开灯\n"); cm_gpio_write(21,CM_GPIO_LOW); }else{ cm_printf("关灯\n"); cm_gpio_write(21,CM_GPIO_HIGH); } break; default: break; } }
服务器部分
前端通过传入lightState来控制GPIO21是高电平还是低电平
@GetMapping(path="hello") public WebResult setGPIOState(int lightState){ // XXXXXX:ProductKey // YYYYYY: 设备名称 PubRequest request = new PubRequest(); request.setProductKey("XXXXXXXXXXXX"); request.setMessageContent(Base64.encodeBase64String((Integer.toString(lightState)).getBytes())); request.setTopicFullName("/XXXXXXXXXX/YYYYYYYYYYY/user/get"); request.setQos(0); //目前支持QoS0和QoS1。 try { PubResponse response = defaultAcsClient.getAcsResponse(request); //System.out.println(response.getSuccess()); //System.out.println(response.getErrorMessage()); } catch (ServerException e) { e.printStackTrace(); } catch (ClientException e) { e.printStackTrace(); } return WebResult.success(1,"hello"); }
前端网页部分
灯光开 灯光关
methods:{ setLightState(state){ console.log(state); // 开关灯 axios({ method: 'get', url: "/iot/hello", params: { 'lightState':state } }).then(res => { console.log(res) }) }, }
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