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Get Object Attributes

s3_get_object_attributes R Documentation

Retrieves all the metadata from an object without returning the object itself

Description

Retrieves all the metadata from an object without returning the object itself. This operation is useful if you're interested only in an object's metadata.

get_object_attributes combines the functionality of head_object and list_parts. All of the data returned with each of those individual calls can be returned with a single call to get_object_attributes.

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 get_object_attributes, you must have READ access to the object. The permissions that you need to use this operation with depend on whether the bucket is versioned. If the bucket is versioned, you need both the s3:GetObjectVersion and s3:GetObjectVersionAttributes permissions for this operation. If the bucket is not versioned, you need the s3:GetObject and s3:GetObjectAttributes permissions. For more information, see Specifying Permissions in a Policy in the Amazon S3 User Guide. If the object that you request does not exist, the error 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 ("no such key") error.

    • If you don't have the s3:ListBucket permission, Amazon S3 returns an HTTP status code ⁠403 Forbidden⁠ ("access denied") error.

  • Directory bucket permissions - To grant access to this API operation on a directory bucket, we recommend that you use the create_session 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 create_session 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 create_session 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 create_session .

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 GET 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

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.

Conditional request headers

Consider the following when using request headers:

  • If both of the If-Match and If-Unmodified-Since headers are present in the request as follows, then Amazon S3 returns the HTTP status code ⁠200 OK⁠ and the data requested:

    • If-Match condition evaluates to true.

    • If-Unmodified-Since condition evaluates to false.

    For more information about conditional requests, see RFC 7232.

  • If both of the If-None-Match and If-Modified-Since headers are present in the request as follows, then Amazon S3 returns the HTTP status code ⁠304 Not Modified⁠:

    • If-None-Match condition evaluates to false.

    • If-Modified-Since condition evaluates to true.

    For more information about conditional requests, see RFC 7232.

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 get_object_attributes:

  • get_object

  • get_object_acl

  • get_object_legal_hold

  • get_object_lock_configuration

  • get_object_retention

  • get_object_tagging

  • head_object

  • list_parts

Usage

s3_get_object_attributes(Bucket, Key, VersionId, MaxParts,
  PartNumberMarker, SSECustomerAlgorithm, SSECustomerKey,
  SSECustomerKeyMD5, RequestPayer, ExpectedBucketOwner, ObjectAttributes)

Arguments

Bucket

[required] 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-az2--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.

Key

[required] The object key.

VersionId

The version ID used to reference a specific version of the object.

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.

MaxParts

Sets the maximum number of parts to return.

PartNumberMarker

Specifies the part after which listing should begin. Only parts with higher part numbers will be listed.

SSECustomerAlgorithm

Specifies the algorithm to use when encrypting the object (for example, AES256).

This functionality is not supported for directory buckets.

SSECustomerKey

Specifies the customer-provided encryption key for Amazon S3 to use in encrypting data. This value is used to store the object and then it is discarded; Amazon S3 does not store the encryption key. The key must be appropriate for use with the algorithm specified in the x-amz-server-side-encryption-customer-algorithm header.

This functionality is not supported for directory buckets.

SSECustomerKeyMD5

Specifies the 128-bit MD5 digest of the encryption key according to RFC 1321. Amazon S3 uses this header for a message integrity check to ensure that the encryption key was transmitted without error.

This functionality is not supported for directory buckets.

RequestPayer
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).

ObjectAttributes

[required] Specifies the fields at the root level that you want returned in the response. Fields that you do not specify are not returned.

Value

A list with the following syntax: 

list(
  DeleteMarker = TRUE|FALSE,
  LastModified = as.POSIXct(
    "2015-01-01"
  ),
  VersionId = "string",
  RequestCharged = "requester",
  ETag = "string",
  Checksum = list(
    ChecksumCRC32 = "string",
    ChecksumCRC32C = "string",
    ChecksumSHA1 = "string",
    ChecksumSHA256 = "string"
  ),
  ObjectParts = list(
    TotalPartsCount = 123,
    PartNumberMarker = 123,
    NextPartNumberMarker = 123,
    MaxParts = 123,
    IsTruncated = TRUE|FALSE,
    Parts = list(
      list(
        PartNumber = 123,
        Size = 123,
        ChecksumCRC32 = "string",
        ChecksumCRC32C = "string",
        ChecksumSHA1 = "string",
        ChecksumSHA256 = "string"
      )
    )
  ),
  StorageClass = "STANDARD"|"REDUCED_REDUNDANCY"|"STANDARD_IA"|"ONEZONE_IA"|"INTELLIGENT_TIERING"|"GLACIER"|"DEEP_ARCHIVE"|"OUTPOSTS"|"GLACIER_IR"|"SNOW"|"EXPRESS_ONEZONE",
  ObjectSize = 123
)

Request syntax

svc$get_object_attributes(
  Bucket = "string",
  Key = "string",
  VersionId = "string",
  MaxParts = 123,
  PartNumberMarker = 123,
  SSECustomerAlgorithm = "string",
  SSECustomerKey = raw,
  SSECustomerKeyMD5 = "string",
  RequestPayer = "requester",
  ExpectedBucketOwner = "string",
  ObjectAttributes = list(
    "ETag"|"Checksum"|"ObjectParts"|"StorageClass"|"ObjectSize"
  )
)