The head_object interface retrieves object metadata without returning the object itself. This article explains how to use the head_object interface in the Rust SDK to perform this operation and handle encryption scenarios such as SSE-C.

Notes

You need to fill in the region and access domain in the sample code according to your actual conditions. For details, see region and access domain.

To prevent key leakage, the sample code reads the Access Key ID and Secret Access Key from environment variables. Before using the SDK, you need to configure long-term credentials. For details, see configure long-term credentials.

If the object is encrypted with SSE-TOS or SSE-KMS, the head_object request must not include x_tos_server_side_encryption headers; otherwise, it returns 400 BadRequest.

If the object is encrypted with SSE-C, the head_object request must include x_tos_server_side_encryption_customer_algorithm, x_tos_server_side_encryption_customer_key, and x_tos_server_side_encryption_customer_key_md5. All three are mandatory.

For symlink objects, ETag, x_tos_storage_class, x_tos_hash_crc64ecma, and x_tos_symlink_target_size return the target object's values; Last-Modified is the later of the symlink and target object; other headers return the symlink object's values.

When the request header includes the version_id parameter, head_object returns metadata for the specified version of the object; if the version does not exist, it responds with 404 Not Found.

Permissions required

The Volcengine main account has all permissions by default, but an IAM user has no permissions by default. If you need a sub-account to perform the head_object operation, the Volcengine main account must grant the following permissions to the sub-account through the IAM policy and bucket policy:

tos:GetObject

Code example

Query object metadata information

Torch Object Storage