MQTT如何連接阿里云訂閱主題

本篇內(nèi)容主要講解“MQTT如何連接阿里云訂閱主題”，感興趣的朋友不妨來看看。本文介紹的方法操作簡單快捷，實(shí)用性強(qiáng)。下面就讓小編來帶大家學(xué)習(xí)“MQTT如何連接阿里云訂閱主題”吧!

中移4G模塊-ML302-OpenCpu開發(fā)-(MQTT連接阿里云-訂閱主題)

模塊OpenCpu部分

cm_main.c文件里面的cm_main_task是主函數(shù),在主函數(shù)里面調(diào)用cm_test_aliyun函數(shù)。

cm_test_aliyun函數(shù)：

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);      //調(diào)用example_subscribe函數(shù)
    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函數(shù)：

example_subscribe一開始進(jìn)行字符串連接，把${YourProductKey}/${YourDeviceName}/user/get拼接出來，然后調(diào)用IOT_MQTT_Subscribe函數(shù)訂閱topic

int example_subscribe(void *handle){
    int res = 0;
    const char *fmt = "/%s/%s/user/get";    //訂閱的MQTT路徑
    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);

    //通過HAL_Snprintf函數(shù)的拼接得出最終的MQTT路徑
    //示例：${YourProductKey}/${YourDeviceName}/user/get
    //其中的：example_message_arrive函數(shù)為接收的數(shù)據(jù)的回調(diào)函數(shù)    

    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函數(shù)

example_subscribe為topic接收回調(diào)函數(shù)，當(dāng)接收到此topic的數(shù)據(jù)時(shí)會(huì)放到這里處理

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為接收到的數(shù)據(jù)

            if(strcmp(topic_info->payload,"1") == 0){
                cm_printf("開燈\n");
                cm_gpio_write(21,CM_GPIO_LOW);
            }else{
                cm_printf("關(guān)燈\n");
                cm_gpio_write(21,CM_GPIO_HIGH);
            }



            break;
        default:
            break;
    }

}

服務(wù)器部分

前端通過傳入lightState來控制GPIO21是高電平還是低電平

@GetMapping(path="hello")
    public WebResult setGPIOState(int lightState){

        // XXXXXX：ProductKey
        // YYYYYY: 設(shè)備名稱

        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");
    }

前端網(wǎng)頁部分

<div class="my-2 my-tab">
                <v-btn small @click="setLightState(1)">燈光開</v-btn>
                <v-btn small  @click="setLightState(0)">燈光關(guān)</v-btn>
            </div>

methods:{
        setLightState(state){
            console.log(state);
            // 開關(guān)燈
            axios({
                method: 'get',
                url: "/iot/hello",
                params: {
                    'lightState':state
                }
            }).then(res => {
                console.log(res)
            })
        },
    }

到此，相信大家對(duì)“MQTT如何連接阿里云訂閱主題”有了更深的了解，不妨來實(shí)際操作一番吧！這里是億速云網(wǎng)站，更多相關(guān)內(nèi)容可以進(jìn)入相關(guān)頻道進(jìn)行查詢，關(guān)注我們，繼續(xù)學(xué)習(xí)！