# 订阅主题 - SubscribeTopic
#### 功能介绍
订阅终端确认订阅主题消息。
#### 调用方法
请参见[如何调用API](https://support.huaweicloud.com/api-smn/smn_api_30000.html)。
#### 授权信息
账号具备所有API的调用权限，如果使用账号下的IAM用户调用当前API，该IAM用户需具备调用API所需的权限。
- 如果使用角色与策略授权，具体权限要求请参见[权限和授权项](https://support.huaweicloud.com/api-smn/smn_api_80000.html)。
- 如果使用身份策略授权，当前API调用无需身份策略权限。
 
#### URI
GET /v2/notifications/subscriptions/subscribe
表1Query参数 
| 参数        | 是否必选 | 参数类型   | 描述                                                                                                                                                                                  |
|:---|:---|:---|:---|
| topic_urn | 否    | String | Topic的唯一的资源标识，可通过[查询主题列表](https://support.huaweicloud.com/api-smn/smn_api_51004.html)获取该标识。当订阅类型为短信或邮件时，与token、endpoint参数组合使用，三个参数中设置任意两个或全部设置均可确认订阅成功；当订阅类型为其他时，该参数必填，需与token同时设置。 |
| endpoint  | 否    | String | 订阅终端地址。仅当订阅类型为短信或邮件时可设置，与token、topic_urn参数组合使用，三个参数中设置任意两个或全部设置均可确认订阅成功。                                                                                                            |
| token     | 是    | String | 确认订阅Token信息。（订阅链接中携带的token信息）                                                                                                                                                       |
   
#### 请求参数
无
#### 响应参数
**状态码：200**
表2响应Body参数 
| 参数               | 参数类型   | 描述           |
|:---|:---|:---|
| request_id       | String | 请求的唯一标识ID。   |
| subscription_urn | String | 订阅者的唯一的资源标识。 |
   
**状态码：400**
表3响应Body参数 
| 参数      | 参数类型   | 描述    |
|:---|:---|:---|
| message | String | 响应信息。 |
   
**状态码：403**
表4响应Body参数 
| 参数      | 参数类型   | 描述    |
|:---|:---|:---|
| message | String | 响应信息。 |
   
**状态码：404**
表5响应Body参数 
| 参数      | 参数类型   | 描述    |
|:---|:---|:---|
| message | String | 响应信息。 |
   
**状态码：500**
表6响应Body参数 
| 参数      | 参数类型   | 描述    |
|:---|:---|:---|
| message | String | 响应信息。 |
   
#### 请求示例
订阅主题
```
GET https://{SMN_Endpoint}/v2/notifications/subscriptions/subscribe?topic_urn=urn:smn:regionId:f96188c7ccaf4ffba0c9aa149ab2bd57:test_topic_v2&token=b02df9b03fb84ace995caa6a21c56326b8c9f9e6f3734f2695f3ed2234edbfd90e6d046e93264bd083356abd46bc1217daa483eaf46c469883f91871928bddc6493f34dd49cf4ea2851af5f49bf95297
```
#### 响应示例
**状态码：200**
```
{
  "request_id" : "a10468986ae745f0b3b17683d872f2ef",
  "subscription_urn" : "urn:smn:regionId:240489644ad14ace8e022869d34411a4:test11:b46ac8ad72104818bab55fe5f361e5ca"
}
```
#### SDK代码示例
SDK代码示例如下。
- [Java]
  ```
  package com.huaweicloud.sdk.test;
  import com.huaweicloud.sdk.core.auth.ICredential;
  import com.huaweicloud.sdk.core.auth.BasicCredentials;
  import com.huaweicloud.sdk.core.exception.ConnectionException;
  import com.huaweicloud.sdk.core.exception.RequestTimeoutException;
  import com.huaweicloud.sdk.core.exception.ServiceResponseException;
  import com.huaweicloud.sdk.smn.v2.region.SmnRegion;
  import com.huaweicloud.sdk.smn.v2.*;
  import com.huaweicloud.sdk.smn.v2.model.*;
  public class SubscribeTopicSolution {
      public static void main(String[] args) {
          // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
          // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
          String ak = System.getenv("CLOUD_SDK_AK");
          String sk = System.getenv("CLOUD_SDK_SK");
          ICredential auth = new BasicCredentials()
                  .withAk(ak)
                  .withSk(sk);
          SmnClient client = SmnClient.newBuilder()
                  .withCredential(auth)
                  .withRegion(SmnRegion.valueOf("<YOUR REGION>"))
                  .build();
          SubscribeTopicRequest request = new SubscribeTopicRequest();
          try {
              SubscribeTopicResponse response = client.subscribeTopic(request);
              System.out.println(response.toString());
          } catch (ConnectionException e) {
              e.printStackTrace();
          } catch (RequestTimeoutException e) {
              e.printStackTrace();
          } catch (ServiceResponseException e) {
              e.printStackTrace();
              System.out.println(e.getHttpStatusCode());
              System.out.println(e.getRequestId());
              System.out.println(e.getErrorCode());
              System.out.println(e.getErrorMsg());
          }
      }
  }
  ```
- [Python]
  ```
  # coding: utf-8
  import os
  from huaweicloudsdkcore.auth.credentials import BasicCredentials
  from huaweicloudsdksmn.v2.region.smn_region import SmnRegion
  from huaweicloudsdkcore.exceptions import exceptions
  from huaweicloudsdksmn.v2 import *
  if __name__ == "__main__":
      # The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
      # In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
      ak = os.environ["CLOUD_SDK_AK"]
      sk = os.environ["CLOUD_SDK_SK"]
      credentials = BasicCredentials(ak, sk)
      client = SmnClient.new_builder() \
          .with_credentials(credentials) \
          .with_region(SmnRegion.value_of("<YOUR REGION>")) \
          .build()
      try:
          request = SubscribeTopicRequest()
          response = client.subscribe_topic(request)
          print(response)
      except exceptions.ClientRequestException as e:
          print(e.status_code)
          print(e.request_id)
          print(e.error_code)
          print(e.error_msg)
  ```
- [Go]
  ```
  package main
  import (
  "fmt"
  "github.com/huaweicloud/huaweicloud-sdk-go-v3/core/auth/basic"
      smn "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/smn/v2"
  "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/smn/v2/model"
      region "github.com/huaweicloud/huaweicloud-sdk-go-v3/services/smn/v2/region"
  )
  func main() {
      // The AK and SK used for authentication are hard-coded or stored in plaintext, which has great security risks. It is recommended that the AK and SK be stored in ciphertext in configuration files or environment variables and decrypted during use to ensure security.
      // In this example, AK and SK are stored in environment variables for authentication. Before running this example, set environment variables CLOUD_SDK_AK and CLOUD_SDK_SK in the local environment
      ak := os.Getenv("CLOUD_SDK_AK")
      sk := os.Getenv("CLOUD_SDK_SK")
      auth, err := basic.NewCredentialsBuilder().
          WithAk(ak).
          WithSk(sk).
          SafeBuild()
      if err != nil {
          fmt.Println(err)
          return
      }
      hcClient, err := smn.SmnClientBuilder().
           WithRegion(region.ValueOf("<YOUR REGION>")).
           WithCredential(auth).
           SafeBuild()
      if err != nil {
          fmt.Println(err)
          return
      }
      client := smn.NewSmnClient(hcClient)
      request := &model.SubscribeTopicRequest{}
  response, err := client.SubscribeTopic(request)
  if err == nil {
          fmt.Printf("%+v\n", response)
      } else {
          fmt.Println(err)
      }
  }
  ```
- [更多]
  更多编程语言的SDK代码示例，请参见[API Explorer](https://console.huaweicloud.com/apiexplorer/#/openapi/SMN/sdk?api=SubscribeTopic&version=v2)的代码示例页签，可生成自动对应的SDK代码示例。
#### 状态码
| 状态码 | 描述                    |
|:---|:---|
| 200 | OK                    |
| 400 | Bad Request           |
| 403 | Unauthorized          |
| 404 | Not Found             |
| 500 | Internal Server Error |
   
#### 错误码
请参见[错误码](https://support.huaweicloud.com/api-smn/ErrorCode.html)。