IoT Platform:Example

Step 1: Initialize a client

1. Add header files.

   ...
   ...
   
   #include "aiot_ntp_api.h"

2. Add the underlying dependency and configure the log output feature.

       aiot_sysdep_set_portfile(&g_aiot_sysdep_portfile);
       aiot_state_set_logcb(demo_state_logcb);

3. Call the aiot_ntp_init operation to create an NTP client instance and initialize the default parameters.

       ntp_handle = aiot_ntp_init();
       if (ntp_handle == NULL) {
           demo_mqtt_stop(&mqtt_handle);
           printf("aiot_ntp_init failed\n");
           return -1;
       }

Step 2: Configure required features

Call the aiot_ntp_setopt operation to configure the following items:

• Associate with an MQTT connection handle.
• Set a time zone.
• Configure a message callback.
• Configure a callback to monitor status.

1. Associate with an MQTT connection handle.
   Notice Before you set NTP service-specific parameters, make sure that device authentication information is specified. For more information, see Example.

   • Sample code

         aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_MQTT_HANDLE, mqtt_handle);

   • Parameters:

     Parameter	Example	Description
     AIOT_NTPOPT_MQTT_HANDLE	mqtt_handle	You must establish an MQTT connection. This parameter is used to associate with the MQTT connection handle.

2. Set a time zone.
   • Sample code

         int8_t      time_zone = 8;
         ...
         ...
         aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_TIME_ZONE, (int8_t *)&time_zone);

   • Parameters:

     Parameter	Example	Description
     AIOT_NTPOPT_TIME_ZONE	time_zone	The time zone in which the device resides. In this example, time_zone=8 indicates UTC+8. Set a time zone by specifying time_zone. Valid values: -12 to 12. For example, the value -3 indicates UTC-3.

3. Configure a message callback.
   • Sample code

         aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_RECV_HANDLER, (void *)demo_ntp_recv_handler);

   • Parameters:

     Parameter	Example	Description
     AIOT_NTPOPT_RECV_HANDLER	demo_ntp_recv_handler	This function is called when an NTP service message is received.

4. Configure status monitoring.
   1. Define the callback to monitor status.

      void demo_ntp_event_handler(void *handle, const aiot_ntp_event_t *event, void *userdata)
      {
          switch (event->type) {
              case AIOT_NTPEVT_INVALID_RESPONSE: {
                  printf("AIOT_NTPEVT_INVALID_RESPONSE\n");
              }
              break;
              case AIOT_NTPEVT_INVALID_TIME_FORMAT: {
                  printf("AIOT_NTPEVT_INVALID_TIME_FORMAT\n");
              }
              break;
              default: {
      
              }
          }
      }

   2. Specify the callbacks to monitor status.
      • Sample code

            aiot_ntp_setopt(ntp_handle, AIOT_NTPOPT_EVENT_HANDLER, (void *)demo_ntp_event_handler);

      • Parameters:

        Parameter	Example	Description
        AIOT_NTPOPT_EVENT_HANDLER	demo_ntp_event_handler	When the status of device connection changes, the callback is called to perform the required operations.

Step 3: Send a request

Call the aiot_ntp_send_request operation to send the current time of the device to the server by using the /ext/ntp/${YourProductKey}/${YourDeviceName}/request topic. For more information about the parameters, see the previous step.

Link SDK can automatically submit the current time of the device by calling the API operation.

    res = aiot_ntp_send_request(ntp_handle);
    if (res < STATE_SUCCESS) {
        aiot_ntp_deinit(&ntp_handle);
        demo_mqtt_stop(&mqtt_handle);
        return -1;
    }

Step 4: Receive a response

After the device receives the NTP service message, the demo_ntp_recv_handler callback is called to perform the required operations.

• IoT Platform sends the server time to the device by using the /ext/ntp/${YourProductKey}/${YourDeviceName}/response topic.

• aiot_ntp_recv_t indicates the data format. For more information, see the sample code.

• In this example, after the response message is parsed, the packet pointer is used to print the parsed message.

void demo_ntp_recv_handler(void *handle, const aiot_ntp_recv_t *packet, void *userdata)
{
    switch (packet->type) {
        /* TODO: Parse and store the time information in the current time zone. The time information includes the year, month, day, hour, minute, and second. */
        case AIOT_NTPRECV_LOCAL_TIME: {
            printf("local time: %llu, %02d/%02d/%02d-%02d:%02d:%02d:%d\n",
                   (long long unsigned int)packet->data.local_time.timestamp,
                   packet->data.local_time.year,
                   packet->data.local_time.mon, packet->data.local_time.day, packet->data.local_time.hour, packet->data.local_time.min,
                   packet->data.local_time.sec, packet->data.local_time.msec);
        }
        break;

        default: {

        }
    }
}

Step 5: Exit the program

Call the aiot_ntp_deinit operation to destroy the NTP client instance and release resources.

    res = aiot_ntp_deinit(&ntp_handle);
    if (res < STATE_SUCCESS) {
        demo_mqtt_stop(&mqtt_handle);
        printf("aiot_ntp_deinit failed: -0x%04X\n", -res);
        return -1;
    }