HEAD Object
Suggest changes
PDFs
You can use the S3 HEAD Object request to retrieve metadata from an object without returning the object itself. If the object is stored in a Cloud Storage Pool, you can use HEAD Object to determine the object's transition state.
HEAD object and multipart objects
You can use the partNumber request parameter to retrieve metadata for a specific part of a multipart or segmented object. The x-amz-mp-parts-count response element indicates how many parts the object has.
You can set partNumber to 1 for both segmented/multipart objects and non-segmented/non-multipart objects; however, the x-amz-mp-parts-count response element is only returned for segmented or multipart objects.
Request headers for server-side encryption with customer-provided encryption keys (SSE-C)
Use all three of these headers if the object is encrypted with a unique key that you provided.
-
x-amz-server-side-encryption-customer-algorithm: SpecifyAES256. -
x-amz-server-side-encryption-customer-key: Specify your encryption key for the object. -
x-amz-server-side-encryption-customer-key-MD5: Specify the MD5 digest of the object's encryption key.
|
The encryption keys you provide are never stored. If you lose an encryption key, you lose the corresponding object. Before using customer-provided keys to secure object data, review the considerations in “Use server-side encryption.” |
UTF-8 characters in user metadata
StorageGRID does not parse or interpret escaped UTF-8 characters in user-defined metadata. HEAD requests for an object with escaped UTF-8 characters in user-defined metadata do not return the x-amz-missing-meta header if the key name or value includes unprintable characters.
Unsupported request header
The following request header is not supported and returns XNotImplemented:
-
x-amz-website-redirect-location
Response headers for Cloud Storage Pool objects
If the object is stored in a Cloud Storage Pool (see the instructions for managing objects with information lifecycle management), the following response headers are returned:
-
x-amz-storage-class: GLACIER -
x-amz-restore
The response headers provide information about the state of an object as it is moved to a Cloud Storage Pool, optionally transitioned to a non-retrievable state, and restored.
| State of object | Response to HEAD object |
|---|---|
Object ingested into StorageGRID but not yet evaluated by ILM, or object stored in a traditional storage pool or using erasure coding |
|
Object in Cloud Storage Pool but not yet transitioned to a non-retrievable state |
Until the object is transitioned to a non-retrievable state, the value for |
Object has transitioned to non-retrievable state, but at least one copy also exists on the grid |
The value for Note: If the copy on the grid is not available (for example, a Storage Node is down), you must issue a POST Object restore request to restore the copy from the Cloud Storage Pool before you can successfully retrieve the object. |
Object transitioned to a non-retrievable state, and no copy exists on the grid |
|
Object in process of being restored from a non-retrievable state |
|
Object fully restored to the Cloud Storage Pool |
The |
Multipart or segmented objects in Cloud Storage Pool
If you uploaded a multipart object or if StorageGRID split a large object into segments, StorageGRID determines whether the object is available in the Cloud Storage Pool by sampling a subset of the object's parts or segments. In some cases, a HEAD Object request might incorrectly return x-amz-restore: ongoing-request="false" when some parts of the object have already been transitioned to a non-retrievable state or when some parts of the object have not yet been restored.
Versioning
If a versionId subresource is not specified, the operation fetches the most recent version of the object in a versioned bucket. If the current version of the object is a delete marker, a “Not Found” status is returned with the x-amz-delete-marker response header set to true.