GetObjectMetadataRequest Class | AWS SDK for .NET V3

Container for the parameters to the GetObjectMetadata operation. The HEAD operation retrieves metadata from an object without returning the object itself. This operation is useful if you're interested only in an object's metadata.

A HEAD request has the same options as a GET operation 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 code, such as 400 Bad Request, 403 Forbidden, 404 Not Found, 405 Method Not Allowed, 412 Precondition Failed, or 304 Not Modified. It's not possible to retrieve the exact exception of these error codes.

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

Directory buckets - For 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://bucket_name.s3express-az_id.region.amazonaws.com/key-name. Path-style requests are not supported. For more information, see Regional and Zonal endpoints in the Amazon S3 User Guide.

Permissions

General purpose bucket permissions - To use HEAD, you must have the s3:GetObject permission. You need the relevant read object (or version) permission for this operation. For more information, see Actions, resources, and condition keys for Amazon S3 in the Amazon S3 User Guide.
If the object you request doesn't exist, the error that Amazon S3 returns depends on whether you also have the s3:ListBucket permission.
- If you have the s3:ListBucket permission on the bucket, Amazon S3 returns an HTTP status code 404 Not Found error.
- If you don’t have the s3:ListBucket permission, Amazon S3 returns an HTTP status code 403 Forbidden error.
Directory bucket permissions - To grant access to this API operation on a directory bucket, we recommend that you use the CreateSession API operation for session-based authorization. Specifically, you grant the s3express:CreateSession permission to the directory bucket in a bucket policy or an IAM identity-based policy. Then, you make the CreateSession API call on the bucket to obtain a session token. With the session token in your request header, you can make API requests to this operation. After the session token expires, you make another CreateSession API call to generate a new session token for use. Amazon Web Services CLI or SDKs create session and refresh the session token automatically to avoid service interruptions when a session expires. For more information about authorization, see CreateSession.

Encryption

Encryption request headers, like x-amz-server-side-encryption, should not be sent for HEAD requests if your object uses server-side encryption with Key Management Service (KMS) keys (SSE-KMS), dual-layer server-side encryption with Amazon Web Services KMS keys (DSSE-KMS), or server-side encryption with Amazon S3 managed encryption keys (SSE-S3). The x-amz-server-side-encryption header is used when you PUT an object to S3 and want to specify the encryption method. If you include this header in a HEAD request for an object that uses these types of keys, you’ll get an HTTP 400 Bad Request error. It's because the encryption method can't be changed when you retrieve the object.

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 to provide the encryption key for the server to be able to retrieve the object's metadata. The headers are:

x-amz-server-side-encryption-customer-algorithm
x-amz-server-side-encryption-customer-key
x-amz-server-side-encryption-customer-key-MD5

For more information about SSE-C, see Server-Side Encryption (Using Customer-Provided Encryption Keys) in the Amazon S3 User Guide.

Directory bucket permissions - For directory buckets, only server-side encryption with Amazon S3 managed keys (SSE-S3) (AES256) is supported.

Versioning

If the current version of the object is a delete marker, Amazon S3 behaves as if the object was deleted and includes x-amz-delete-marker: true in the response.
If the specified version is a delete marker, the response returns a 405 Method Not Allowed error and the Last-Modified: timestamp response header.

Directory buckets - Delete marker is not supported by directory buckets.
Directory buckets - S3 Versioning isn't enabled and supported for directory buckets. For this API operation, only the null value of the version ID is supported by directory buckets. You can only specify null to the versionId query parameter in the request.

HTTP Host header syntax

Directory buckets - The HTTP Host header syntax is Bucket_name.s3express-az_id.region.amazonaws.com.

The following actions are related to HeadObject:

Inheritance Hierarchy

System.Object
Amazon.Runtime.AmazonWebServiceRequest
Amazon.S3.Model.GetObjectMetadataRequest

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

Syntax

public class GetObjectMetadataRequest : AmazonWebServiceRequest
         IAmazonWebServiceRequest

The GetObjectMetadataRequest type exposes the following members

Constructors

	Name	Description
	GetObjectMetadataRequest()

Properties

Name	Type	Description
BucketName	System.String	Gets and sets the property BucketName. The name of the bucket that contains the object. Directory buckets - When you use this operation with a directory bucket, you must use virtual-hosted-style requests in the format `Bucket_name.s3express-az_id.region.amazonaws.com`. Path-style requests are not supported. Directory bucket names must be unique in the chosen Availability Zone. Bucket names must follow the format `bucket_base_name--az-id--x-s3` (for example, `DOC-EXAMPLE-BUCKET--usw2-az1--x-s3`). For information about bucket naming restrictions, see Directory bucket naming rules in the Amazon S3 User Guide. Access points - When you use this action with an access point, you must provide the alias of the access point in place of the bucket name or specify the access point ARN. When using the access point ARN, 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. Access points and Object Lambda access points are not supported by directory buckets. S3 on Outposts - When you use 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 you use this action with S3 on Outposts through the Amazon Web Services SDKs, you provide the Outposts access point ARN in place of the bucket name. For more information about S3 on Outposts ARNs, see What is S3 on Outposts? in the Amazon S3 User Guide.
ChecksumMode	Amazon.S3.ChecksumMode	Gets and sets the property ChecksumMode. This must be enabled to retrieve the checksum. In addition, if you enable `ChecksumMode` and the object is KMS encrypted, you must have permission to the `kms:Decrypt` action for the request to succeed.
EtagToMatch	System.String	ETag to be matched as a pre-condition for returning the object, otherwise a PreconditionFailed signal is returned.
EtagToNotMatch	System.String	ETag that should not be matched as a pre-condition for returning the object, otherwise a NotModified (304) signal is returned.
ExpectedBucketOwner	System.String	Gets and sets the property ExpectedBucketOwner. The account ID of the expected bucket owner. If the account ID that you provide does not match the actual owner of the bucket, the request fails with the HTTP status code `403 Forbidden` (access denied).
Key	System.String	The key of the object.
ModifiedSinceDate	System.DateTime	This property is deprecated. Setting this property results in non-UTC DateTimes not being marshalled correctly. Use ModifiedSinceDateUtc instead. Setting either ModifiedSinceDate or ModifiedSinceDateUtc results in both ModifiedSinceDate and ModifiedSinceDateUtc being assigned, the latest assignment to either one of the two property is reflected in the value of both. ModifiedSinceDate is provided for backwards compatibility only and assigning a non-Utc DateTime to it results in the wrong timestamp being passed to the service. Returns the object only if it has been modified since the specified time, otherwise returns a PreconditionFailed.
ModifiedSinceDateUtc	System.DateTime	Returns the object only if it has been modified since the specified time, otherwise returns a PreconditionFailed.
PartNumber	System.Nullable<System.Int32>	Part number of the object being read. This is a positive integer between 1 and 10,000. Effectively performs a 'ranged' HEAD request for the part specified. Useful querying about the size of the part and the number of parts in this object.
RequestPayer	Amazon.S3.RequestPayer	Confirms that the requester knows that she or he will be charged for the request. Bucket owners need not specify this parameter in their requests.
ServerSideEncryptionCustomerMethod	Amazon.S3.ServerSideEncryptionCustomerMethod	The Server-side encryption algorithm to be used with the customer provided key. This functionality is not supported for directory buckets.
ServerSideEncryptionCustomerProvidedKey	System.String	The base64-encoded encryption key for Amazon S3 to use to decrypt the object Using the encryption key you provide as part of your request Amazon S3 manages both the encryption, as it writes to disks, and decryption, when you access your objects. Therefore, you don't need to maintain any data encryption code. The only thing you do is manage the encryption keys you provide. When you retrieve an object, you must provide the same encryption key as part of your request. Amazon S3 first verifies the encryption key you provided matches, and then decrypts the object before returning the object data to you. Important: Amazon S3 does not store the encryption key you provide. This functionality is not supported for directory buckets.
ServerSideEncryptionCustomerProvidedKeyMD5	System.String	The MD5 of the customer encryption key specified in the ServerSideEncryptionCustomerProvidedKey property. The MD5 is base 64 encoded. This field is optional, the SDK will calculate the MD5 if this is not set.
UnmodifiedSinceDate	System.DateTime	This property is deprecated. Setting this property results in non-UTC DateTimes not being marshalled correctly. Use UnmodifiedSinceDateUtc instead. Setting either UnmodifiedSinceDate or UnmodifiedSinceDateUtc results in both UnmodifiedSinceDate and UnmodifiedSinceDateUtc being assigned, the latest assignment to either one of the two property is reflected in the value of both. UnmodifiedSinceDate is provided for backwards compatibility only and assigning a non-Utc DateTime to it results in the wrong timestamp being passed to the service. Returns the object only if it has not been modified since the specified time, otherwise returns a PreconditionFailed.
UnmodifiedSinceDateUtc	System.DateTime	Returns the object only if it has not been modified since the specified time, otherwise returns a PreconditionFailed.
VersionId	System.String	Gets and sets the property VersionId. Version ID used to reference a specific version of the object. For directory buckets in this API operation, only the `null` value of the version ID is supported.

Version Information

.NET Core App:
Supported in: 3.1

.NET Standard:
Supported in: 2.0

.NET Framework:
Supported in: 4.5, 4.0, 3.5