You can use HeadBucket to retrieve information about a bucket. Additionally, the HTTP Code in the returned error can be used to determine whether the bucket exists. This article describes how to obtain bucket metadata and determine whether a bucket exists.

Precautions

Before you can retrieve bucket metadata, you must have the tos:HeadBucket permission.

If the bucket does not exist, the interface will return a 404 error code; it is also commonly used to determine whether a bucket exists.

Sample Code

Determine whether the bucket exists

import { TosClient, TosClientError, TosServerError } from '@volcengine/tos_harmonyos_sdk';​
​
​
const client = new TosClient({​
  accessKeyId: "Provide your ak",​
  accessKeySecret: "Provide your sk",​
  securityToken: 'Provide your securityToken',​
  region: "Provide your region",  ​
  endpoint: "Provide your endpoint", ​
});​
​
function handleError(error: Error) {​
 if (error instanceof TosClientError) {​
   console.log('Client Err Msg:', error.message);​
   console.log('Client Err Stack:', error.stack);​
 } else if (error instanceof TosServerError) {​
   console.log('Request ID:', error.requestId);​
   console.log('Response Status Code:', error.statusCode);​
   console.log('Response Header:', error.headers);​
   console.log('Response Err Code:', error.code);​
   console.log('Response Err Msg:', error.message);​
 } else {​
   console.log('unexpected exception, message: ', error);​
 }​
}​
​
const bucketName = 'harmonyos-sdk-test-bucket';​
async function main() {​
  try {​
   ​
    const res = await client.headBucket({​
      Bucket: bucketName​
    });​
​
    console.log(`the region of ${bucketName} is`, res.Region);​
    console.log(`the storageClass of ${bucketName} is`, res.StorageClass);​
  } catch (error) {​
    if (error instanceof TosServerError) {​
      if (error.StatusCode === 404) {​
       ​
        console.log('Bucket not found.');​
        return;​
      }​
    }​
​
    handleError(error);​
  }​
}​
​
main();​

Retrieve Bucket Metadata

import { TosClient, TosClientError, TosServerError } from '@volcengine/tos_harmonyos_sdk';​
​
​
const client = new TosClient({​
  accessKeyId: "Provide your ak",​
  accessKeySecret: "Provide your sk",​
  securityToken: 'Provide your securityToken',​
  region: "Provide your region", ​
  endpoint: "Provide your endpoint", ​
});​
​
function handleError(error: Error) {​
 if (error instanceof TosClientError) {​
   console.log('Client Err Msg:', error.message);​
   console.log('Client Err Stack:', error.stack);​
 } else if (error instanceof TosServerError) {​
   console.log('Request ID:', error.requestId);​
   console.log('Response Status Code:', error.statusCode);​
   console.log('Response Header:', error.headers);​
   console.log('Response Err Code:', error.code);​
   console.log('Response Err Msg:', error.message);​
 } else {​
   console.log('unexpected exception, message: ', error);​
 }​
}​
​
const bucketName = 'harmonyos-sdk-test-bucket';​
async function main() {​
  try {​
   ​
    const res = await client.headBucket({​
      Bucket: bucketName​
    });​
​
    console.log(`the region of ${bucketName} is`, res.Region);​
    console.log(`the storageClass of ${bucketName} is`, res.StorageClass);​
    console.log(`the azRedundancy of ${bucketName} is`, res.AzRedundancy)​
  } catch (error) {​
    handleError(error);​
  }​
}​
​
main();​