前提條件

• 已創建網關與子設備。具體操作，請參見網關與子設備。

  • 為網關創建對應的產品和設備，創建產品時，節點類型選擇為網關設備。

  • 為子設備創建對應的產品和設備，創建產品時，節點類型選擇為網關子設備。

• 已下載C LinkSDK Extended。具體操作，請參見獲取SDK。

使用流程

如下功能時序圖，以設備的應用程序demos/gateway_sync_demo.c和demos/gateway_async_demo.c為例，介紹網關模塊的基礎功能。

步驟1：初始化網關設備

1. 添加頭文件。

   #include "aiot_gateway_api.h"
   
       /* 配置SDK的底層依賴 */
       aiot_sysdep_init(aiot_sysdep_get_portfile());

2. 實現網關設備初始化函數。

   該函數包含創建設備句柄、連接參數配置、網關設備建連。

   static void* demo_gateway_device_init(char *product_key, char *device_name, char *device_secret, char *host, uint16_t port)
   {
       int32_t res = STATE_SUCCESS;
       /* 創建設備 */
       void *device = aiot_device_create(product_key, device_name);
       if (device == NULL) {
           printf("device create failed\n");
           return NULL;
       }
       /* 設置設備密鑰 */
       aiot_device_set_device_secret(device, device_secret);
   
       /* 連接配置參數初始化 */
       aiot_linkconfig_t* config = aiot_linkconfig_init(protocol);
       /* 設置服務器的host、port */
       aiot_linkconfig_host(config, host, port);
   
       /* 設置設備連接參數 */
       aiot_device_set_linkconfig(device, config);
       
       /* 設備建連 */
       res = aiot_device_connect(device);
       if (res < STATE_SUCCESS) {
           /* 嘗試建立連接失敗, 銷毀MQTT實例, 回收資源 */
           aiot_linkconfig_deinit(&config);
           aiot_device_delete(&device);
           printf("aiot_device_connect failed: -0x%04X\n\r\n", -res);
           return NULL;
       }
   
       /* 建連成功返回設備對象 */
       aiot_linkconfig_deinit(&config);
       return device;
   }

3. 實現網關模塊回調函數。

   /* 網關模塊的消息回調 */
   void demo_gateway_msg_callback(void *device, const aiot_gateway_msg_t *msg, void *userdata)
   {
       switch(msg->type){
           case AIOT_GWRECV_CONNECT_REPLY:{
               /* 子設備批量建連返回 */
           }
           break;
           case AIOT_GWRECV_DISCONNECT_REPLY:{
               /* 子設備批量斷連結果返回 */
           }
           break;
           case AIOT_GWRECV_ADD_TOPO_REPLY:{
               /* 子設備添加topo關系結果返回 */
           }
           break;
           case AIOT_GWRECV_DELETE_TOPO_REPLY:{
               /* 子設備刪除topo關系結果返回 */
           }
           break;
           case AIOT_GWRECV_TOPO_CHANGE_NOTICE:{
               printf("type[%d] subdev_num %d status %d\r\n", msg->type, msg->subdev_num, msg->data.topo_change.status);
           }
           break;
       }
   }

4. 網關設備正常建連后，會設置網關模塊的回調函數。

    /* 網關設備完成初始化，啟動建連，如果失敗返回NULL */
       void *gateway_device = demo_gateway_device_init(gateway_product_key, gateway_device_name, gateway_device_secret, host, port);
       if(gateway_device == NULL) {
           return -1;
       }
       /* 設置網關消息回調 */
       aiot_gateway_set_msg_callback(gateway_device, demo_gateway_msg_callback, NULL);

步驟2：批量添加拓撲關系

• 使用同步接口aiot_gateway_batch_add_topo添加拓撲關系，返回值為STATE_SUCCESS表示添加成功。

   /* 子設備添加topo */
      res = aiot_gateway_batch_add_topo(gateway_device, sub_device_meta, subdev_num);
      if(res >= STATE_SUCCESS) {
          printf("aiot_gateway_batch_add_topo success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_add_topo error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          return -1;
      }

• 使用異步接口aiot_gateway_batch_add_topo_async添加拓撲關系，需在網關模塊的回調函數中監聽類型為AIOT_GWRECV_ADD_TOPO_REPLY的消息，msg->data.reply.code為200表示添加成功。

      /* 子設備添加topo,異步調用 */
      res = aiot_gateway_batch_add_topo_async(gateway_device, sub_device_meta, subdev_num);
      if(res >= STATE_SUCCESS && 0 == demo_wait_expect_resp(&resp.add_topo_resp, 200, timeout_ms)) {
          printf("aiot_gateway_batch_add_topo_async success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_add_topo_async error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          return -1;
      }

步驟3：初始化子設備

初始化子設備包含創建設備句柄、設置設備密鑰、設置子設備回調函數，可以通過回調參數userdata區分具體設備。

void *demo_sub_device_init(aiot_subdev_meta_info_t *device)
{
    /* 創建設備 */
    void *sub_device = aiot_device_create(device->product_key, device->device_name);
    if (sub_device == NULL) {
        printf("subdev_device failed\n");
        return NULL;
    }
    /* 設置設備密鑰 */
    aiot_device_set_device_secret(sub_device, device->device_secret);
    /* 設置設備消息回調及狀態變化回調
     * demo中子設備與網關設備使用的相同回調函數，最后的參數userdata可設置不同參數以做區分
     * */
    aiot_device_set_event_callback(sub_device, demo_msg_callback, demo_status_callback, demo_result_callback, NULL);
    return sub_device;
}

步驟4：子設備接入物聯網平臺

• 使用同步接口aiot_gateway_batch_connect_subdev接入物聯網平臺，返回值為STATE_SUCCESS表示接入成功。

   /* 子設備建連，同步接口 */
      res = aiot_gateway_batch_connect_subdev(gateway_device, subdev_table, subdev_num);
      if(res >= STATE_SUCCESS) {
          printf("aiot_gateway_batch_connect_subdev success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_connect_subdev error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

• 使用異步接口aiot_gateway_batch_connect_subdev_async接入物聯網平臺，需在網關模塊的回調函數中監聽類型為AIOT_GWRECV_CONNECT_REPLY的消息，msg->data.reply.code為200表示接入成功。

   /* 子設備建連，異步接口 */
      res = aiot_gateway_batch_connect_subdev_async(gateway_device, subdev_table, subdev_num);
      if(res >= STATE_SUCCESS && 0 == demo_wait_expect_resp(&resp.connect_resp, 200, timeout_ms)) {
          printf("aiot_gateway_batch_connect_subdev_async success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_connect_subdev_async error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

步驟5：子設備發送物模型消息

 char *property_params = "{\"LightSwitch\": 0}";
    for(i = 0; i < sizeof(sub_device_meta) / sizeof(aiot_subdev_meta_info_t); i++) {
        /* 子設備發送物模型消息 */
        aiot_device_dm_property_post(subdev_table[i], property_params, 1);
    }
    /* 網關發送物模型消息 */
    aiot_device_dm_property_post(gateway_device, property_params, 1);

步驟6：子設備退出物聯網平臺

• 使用同步接口aiot_gateway_batch_disconnect_subdev退出物聯網平臺，返回值為STATE_SUCCESS表示退出成功。

    /* 子設備斷開連接 */
      res = aiot_gateway_batch_disconnect_subdev(gateway_device, subdev_table, subdev_num);
      if(res >= STATE_SUCCESS) {
          printf("aiot_gateway_batch_disconnect_subdev success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_disconnect_subdev error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

• 使用異步接口aiot_gateway_batch_disconnect_subdev_async退出物聯網平臺，需在網關模塊的回調函數中監聽類型為AIOT_GWRECV_DISCONNECT_REPLY的消息，msg->data.reply.code為200表示退出成功。

   /* 子設備斷開連接 */
      res = aiot_gateway_batch_disconnect_subdev_async(gateway_device, subdev_table, subdev_num);
      if(res >= STATE_SUCCESS && 0 == demo_wait_expect_resp(&resp.disconnect_resp, 200, timeout_ms)) {
          printf("aiot_gateway_batch_disconnect_subdev_async success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_disconnect_subdev_async error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

步驟7：批量刪除拓撲關系

• 使用同步接口aiot_gateway_batch_delete_topo刪除拓撲關系，返回值為STATE_SUCCESS表示刪除成功。

   /* 子設備刪除topo */
      res = aiot_gateway_batch_delete_topo(gateway_device, sub_device_meta, subdev_num);
      if(res >= STATE_SUCCESS) {
          printf("aiot_gateway_batch_delete_topo success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_delete_topo error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

• 使用異步接口aiot_gateway_batch_delete_topo_async刪除拓撲關系，需在網關模塊的回調函數中監聽類型為AIOT_GWRECV_DELETE_TOPO_REPLY的消息，msg->data.reply.code為200表示刪除成功。

   /* 子設備刪除topo */
      res = aiot_gateway_batch_delete_topo_async(gateway_device, sub_device_meta, subdev_num);
      if(res >= STATE_SUCCESS && 0 == demo_wait_expect_resp(&resp.delete_topo_resp, 200, timeout_ms)) {
          printf("aiot_gateway_batch_delete_topo_async success %d\r\n", res);
      } else {
          printf("aiot_gateway_batch_delete_topo_async error %d\r\n", res);
          demo_gateway_device_deinit(gateway_device);
          demo_sub_device_deinit(subdev_table, subdev_num);
          return -1;
      }

步驟8：反初始化子設備

刪除子設備前，將子設備和網關中斷連接，否則會出現內存異常。

void demo_sub_device_deinit(void **subdev_table, int32_t num)
{
    int i = 0;
    for(i = 0; i < num; i++) {
        aiot_device_delete(&subdev_table[i]);
    }

    free(subdev_table);
}

步驟9：反初始化網關設備

static void demo_gateway_device_deinit(void *device)
{
    int32_t res = STATE_SUCCESS;
    res = aiot_device_disconnect(device);
    if (res < STATE_SUCCESS) {
        printf("aiot_device_disconnect failed: -0x%04X\n", -res);
    }
    aiot_device_delete(&device);
}