headBucket

You can use this operation to determine if a bucket exists and if you have permission to access it. The action returns a 200 OK if the bucket exists and you have permission to access it.

If the bucket does not exist or you do not have permission to access it, the HEAD request returns a generic 400 Bad Request, 403 Forbidden or 404 Not Found code. A message body is not included, so you cannot determine the exception beyond these error codes.

**Directory buckets ** - You must make requests for this API operation to the Zonal endpoint. These endpoints support virtual-hosted-style requests in the format https://<i>bucket_name</i>.s3express-<i>az_id</i>.<i>region</i>.amazonaws.com. Path-style requests are not supported. For more information, see Regional and Zonal endpoints in the Amazon S3 User Guide.

Authentication and authorization

All HeadBucket requests must be authenticated and signed by using IAM credentials (access key ID and secret access key for the IAM identities). All headers with the x-amz- prefix, including x-amz-copy-source, must be signed. For more information, see REST Authentication.

Directory bucket - You must use IAM credentials to authenticate and authorize your access to the HeadBucket API operation, instead of using the temporary security credentials through the CreateSession API operation.

Amazon Web Services CLI or SDKs handles authentication and authorization on your behalf.

Permissions

• General purpose bucket permissions - To use this operation, you must have permissions to perform the s3:ListBucket action. The bucket owner has this permission by default and can grant this permission to others. For more information about permissions, see Managing access permissions to your Amazon S3 resources in the Amazon S3 User Guide.

• Directory bucket permissions - You must have the s3express:CreateSession permission in the Action element of a policy. By default, the session is in the ReadWrite mode. If you want to restrict the access, you can explicitly set the s3express:SessionMode condition key to ReadOnly on the bucket.For more information about example bucket policies, see Example bucket policies for S3 Express One Zone and Amazon Web Services Identity and Access Management (IAM) identity-based policies for S3 Express One Zone in the Amazon S3 User Guide.

HTTP Host header syntax

**Directory buckets ** - The HTTP Host header syntax is <i>Bucket_name</i>.s3express-<i>az_id</i>.<i>region</i>.amazonaws.com.

Samples

fun main() { 
   //sampleStart 
   // This operation checks to see if a bucket exists.
s3Client.headBucket {
    bucket = "acl1"
} 
   //sampleEnd
}