AWS SDK Version 3 for .NET
API Reference

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The HEAD action retrieves metadata from an object without returning the object itself. This action is useful if you're only interested in an object's metadata. To use HEAD, you must have READ access to the object.

A HEAD request has the same options as a GET action on an object. The response is identical to the GET response except that there is no response body. Because of this, if the HEAD request generates an error, it returns a generic 404 Not Found or 403 Forbidden code. It is not possible to retrieve the exact exception beyond these error codes.

If you encrypt an object by using server-side encryption with customer-provided encryption keys (SSE-C) when you store the object in Amazon S3, then when you retrieve the metadata from the object, you must use the following headers:

For more information about SSE-C, see Server-Side Encryption (Using Customer-Provided Encryption Keys).

  • Encryption request headers, like x-amz-server-side-encryption, should not be sent for GET requests if your object uses server-side encryption with CMKs stored in Amazon Web Services KMS (SSE-KMS) or server-side encryption with Amazon S3–managed encryption keys (SSE-S3). If your object does use these types of keys, you’ll get an HTTP 400 BadRequest error.

  • The last modified property in this case is the creation date of the object.

Request headers are limited to 8 KB in size. For more information, see Common Request Headers.

Consider the following when using request headers:

For more information about conditional requests, see RFC 7232.

Permissions

You need the relevant read object (or version) permission for this operation. For more information, see Specifying Permissions in a Policy. If the object you request does not exist, the error Amazon S3 returns depends on whether you also have the s3:ListBucket permission.

The following action is related to HeadObject:

Note:

This is an asynchronous operation using the standard naming convention for .NET 4.5 or higher. For .NET 3.5 the operation is implemented as a pair of methods using the standard naming convention of BeginGetObjectMetadata and EndGetObjectMetadata.

Namespace: Amazon.S3
Assembly: AWSSDK.S3.dll
Version: 3.x.y.z

Syntax

C#
public abstract Task<GetObjectMetadataResponse> GetObjectMetadataAsync(
         String bucketName,
         String key,
         String versionId,
         CancellationToken cancellationToken
)
Parameters
bucketName
Type: System.String

The name of the bucket containing the object. When using this action with an access point, you must direct requests to the access point hostname. The access point hostname takes the form AccessPointName-AccountId.s3-accesspoint.Region.amazonaws.com. When using this action with an access point through the Amazon Web Services SDKs, you provide the access point ARN in place of the bucket name. For more information about access point ARNs, see Using access points in the Amazon S3 User Guide. When using this action with Amazon S3 on Outposts, you must direct requests to the S3 on Outposts hostname. The S3 on Outposts hostname takes the form AccessPointName-AccountId.outpostID.s3-outposts.Region.amazonaws.com. When using this action using S3 on Outposts through the Amazon Web Services SDKs, you provide the Outposts bucket ARN in place of the bucket name. For more information about S3 on Outposts ARNs, see Using S3 on Outposts in the Amazon S3 User Guide.

key
Type: System.String

The object key.

versionId
Type: System.String

VersionId used to reference a specific version of the object.

cancellationToken
Type: System.Threading.CancellationToken

A cancellation token that can be used by other objects or threads to receive notice of cancellation.

Return Value
The response from the GetObjectMetadata service method, as returned by S3.

Version Information

.NET Core App:
Supported in: 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5

See Also