HeadObject

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 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.

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:

• 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).

Note

• Encryption request headers, like x-amz-server-side-encryption, should not be sent for GET requests if your object uses server-side encryption with AWS Key Management Service (AWS KMS) keys (SSE-KMS), dual-layer server-side encryption with AWS KMS keys (DSSE-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 Bad Request 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:

• Consideration 1 – If both of the If-Match and If-Unmodified-Since headers are present in the request as follows:

  • If-Match condition evaluates to true, and;

  • If-Unmodified-Since condition evaluates to false;

  Then Amazon S3 returns 200 OK and the data requested.

• Consideration 2 – If both of the If-None-Match and If-Modified-Since headers are present in the request as follows:

  • If-None-Match condition evaluates to false, and;

  • If-Modified-Since condition evaluates to true;

  Then Amazon S3 returns the 304 Not Modified response code.

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 Actions, resources, and condition keys for Amazon S3. 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 error.

• If you don’t have the s3:ListBucket permission, Amazon S3 returns an HTTP status code 403 error.

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.

The following actions are related to HeadObject:

• GetObject

• GetObjectAttributes

Request Syntax

HEAD /Key+?partNumber=PartNumber&versionId=VersionId HTTP/1.1
Host: Bucket.s3.amazonaws.com
If-Match: IfMatch
If-Modified-Since: IfModifiedSince
If-None-Match: IfNoneMatch
If-Unmodified-Since: IfUnmodifiedSince
Range: Range
x-amz-server-side-encryption-customer-algorithm: SSECustomerAlgorithm
x-amz-server-side-encryption-customer-key: SSECustomerKey
x-amz-server-side-encryption-customer-key-MD5: SSECustomerKeyMD5
x-amz-request-payer: RequestPayer
x-amz-expected-bucket-owner: ExpectedBucketOwner
x-amz-checksum-mode: ChecksumMode

URI Request Parameters

The request uses the following URI parameters.

Bucket

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 AWS 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 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 AWS 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.

Required: Yes

If-Match

Return the object only if its entity tag (ETag) is the same as the one specified; otherwise, return a 412 (precondition failed) error.

If-Modified-Since

Return the object only if it has been modified since the specified time; otherwise, return a 304 (not modified) error.

If-None-Match

Return the object only if its entity tag (ETag) is different from the one specified; otherwise, return a 304 (not modified) error.

If-Unmodified-Since

Return the object only if it has not been modified since the specified time; otherwise, return a 412 (precondition failed) error.

Key

The object key.

Length Constraints: Minimum length of 1.

Required: Yes

partNumber

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.

Range

HeadObject returns only the metadata for an object. If the Range is satisfiable, only the ContentLength is affected in the response. If the Range is not satisfiable, S3 returns a 416 - Requested Range Not Satisfiable error.

versionId

VersionId used to reference a specific version of the object.

x-amz-checksum-mode

To retrieve the checksum, this parameter must be enabled.

In addition, if you enable ChecksumMode and the object is encrypted with AWS Key Management Service (AWS KMS), you must have permission to use the kms:Decrypt action for the request to succeed.

Valid Values: ENABLED

x-amz-expected-bucket-owner

The account ID of the expected bucket owner. If the bucket is owned by a different account, the request fails with the HTTP status code 403 Forbidden (access denied).

x-amz-request-payer

Confirms that the requester knows that they will be charged for the request. Bucket owners need not specify this parameter in their requests. If either the source or destination Amazon S3 bucket has Requester Pays enabled, the requester will pay for corresponding charges to copy the object. For information about downloading objects from Requester Pays buckets, see Downloading Objects in Requester Pays Buckets in the Amazon S3 User Guide.

Valid Values: requester

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

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

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

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.

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

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.

Request Body

The request does not have a request body.

Response Syntax

HTTP/1.1 200
x-amz-delete-marker: DeleteMarker
accept-ranges: AcceptRanges
x-amz-expiration: Expiration
x-amz-restore: Restore
x-amz-archive-status: ArchiveStatus
Last-Modified: LastModified
Content-Length: ContentLength
x-amz-checksum-crc32: ChecksumCRC32
x-amz-checksum-crc32c: ChecksumCRC32C
x-amz-checksum-sha1: ChecksumSHA1
x-amz-checksum-sha256: ChecksumSHA256
ETag: ETag
x-amz-missing-meta: MissingMeta
x-amz-version-id: VersionId
Cache-Control: CacheControl
Content-Disposition: ContentDisposition
Content-Encoding: ContentEncoding
Content-Language: ContentLanguage
Content-Type: ContentType
Expires: Expires
x-amz-website-redirect-location: WebsiteRedirectLocation
x-amz-server-side-encryption: ServerSideEncryption
x-amz-server-side-encryption-customer-algorithm: SSECustomerAlgorithm
x-amz-server-side-encryption-customer-key-MD5: SSECustomerKeyMD5
x-amz-server-side-encryption-aws-kms-key-id: SSEKMSKeyId
x-amz-server-side-encryption-bucket-key-enabled: BucketKeyEnabled
x-amz-storage-class: StorageClass
x-amz-request-charged: RequestCharged
x-amz-replication-status: ReplicationStatus
x-amz-mp-parts-count: PartsCount
x-amz-object-lock-mode: ObjectLockMode
x-amz-object-lock-retain-until-date: ObjectLockRetainUntilDate
x-amz-object-lock-legal-hold: ObjectLockLegalHoldStatus

Response Elements

If the action is successful, the service sends back an HTTP 200 response.

The response returns the following HTTP headers.

accept-ranges

Indicates that a range of bytes was specified.

Cache-Control

Specifies caching behavior along the request/reply chain.

Content-Disposition

Specifies presentational information for the object.

Content-Encoding

Specifies what content encodings have been applied to the object and thus what decoding mechanisms must be applied to obtain the media-type referenced by the Content-Type header field.

Content-Language

The language the content is in.

Content-Length

Size of the body in bytes.

Content-Type

A standard MIME type describing the format of the object data.

ETag

An entity tag (ETag) is an opaque identifier assigned by a web server to a specific version of a resource found at a URL.

Expires

The date and time at which the object is no longer cacheable.

Last-Modified

Date and time when the object was last modified.

x-amz-archive-status

The archive state of the head object.

Valid Values: ARCHIVE_ACCESS | DEEP_ARCHIVE_ACCESS

x-amz-checksum-crc32

The base64-encoded, 32-bit CRC32 checksum of the object. This will only be present if it was uploaded with the object. With multipart uploads, this may not be a checksum value of the object. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

x-amz-checksum-crc32c

The base64-encoded, 32-bit CRC32C checksum of the object. This will only be present if it was uploaded with the object. With multipart uploads, this may not be a checksum value of the object. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

x-amz-checksum-sha1

The base64-encoded, 160-bit SHA-1 digest of the object. This will only be present if it was uploaded with the object. With multipart uploads, this may not be a checksum value of the object. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

x-amz-checksum-sha256

The base64-encoded, 256-bit SHA-256 digest of the object. This will only be present if it was uploaded with the object. With multipart uploads, this may not be a checksum value of the object. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

x-amz-delete-marker

Specifies whether the object retrieved was (true) or was not (false) a Delete Marker. If false, this response header does not appear in the response.

x-amz-expiration

If the object expiration is configured (see PUT Bucket lifecycle), the response includes this header. It includes the expiry-date and rule-id key-value pairs providing object expiration information. The value of the rule-id is URL-encoded.

x-amz-missing-meta

This is set to the number of metadata entries not returned in x-amz-meta headers. This can happen if you create metadata using an API like SOAP that supports more flexible metadata than the REST API. For example, using SOAP, you can create metadata whose values are not legal HTTP headers.

x-amz-mp-parts-count

The count of parts this object has. This value is only returned if you specify partNumber in your request and the object was uploaded as a multipart upload.

x-amz-object-lock-legal-hold

Specifies whether a legal hold is in effect for this object. This header is only returned if the requester has the s3:GetObjectLegalHold permission. This header is not returned if the specified version of this object has never had a legal hold applied. For more information about S3 Object Lock, see Object Lock.

Valid Values: ON | OFF

x-amz-object-lock-mode

The Object Lock mode, if any, that's in effect for this object. This header is only returned if the requester has the s3:GetObjectRetention permission. For more information about S3 Object Lock, see Object Lock.

Valid Values: GOVERNANCE | COMPLIANCE

x-amz-object-lock-retain-until-date

The date and time when the Object Lock retention period expires. This header is only returned if the requester has the s3:GetObjectRetention permission.

x-amz-replication-status

Amazon S3 can return this header if your request involves a bucket that is either a source or a destination in a replication rule.

In replication, you have a source bucket on which you configure replication and destination bucket or buckets where Amazon S3 stores object replicas. When you request an object (GetObject) or object metadata (HeadObject) from these buckets, Amazon S3 will return the x-amz-replication-status header in the response as follows:

• If requesting an object from the source bucket, Amazon S3 will return the x-amz-replication-status header if the object in your request is eligible for replication.

  For example, suppose that in your replication configuration, you specify object prefix TaxDocs requesting Amazon S3 to replicate objects with key prefix TaxDocs. Any objects you upload with this key name prefix, for example TaxDocs/document1.pdf, are eligible for replication. For any object request with this key name prefix, Amazon S3 will return the x-amz-replication-status header with value PENDING, COMPLETED or FAILED indicating object replication status.

• If requesting an object from a destination bucket, Amazon S3 will return the x-amz-replication-status header with value REPLICA if the object in your request is a replica that Amazon S3 created and there is no replica modification replication in progress.

• When replicating objects to multiple destination buckets, the x-amz-replication-status header acts differently. The header of the source object will only return a value of COMPLETED when replication is successful to all destinations. The header will remain at value PENDING until replication has completed for all destinations. If one or more destinations fails replication the header will return FAILED.

For more information, see Replication.

Valid Values: COMPLETE | PENDING | FAILED | REPLICA

x-amz-request-charged

If present, indicates that the requester was successfully charged for the request.

Valid Values: requester

x-amz-restore

If the object is an archived object (an object whose storage class is GLACIER), the response includes this header if either the archive restoration is in progress (see RestoreObject or an archive copy is already restored.

If an archive copy is already restored, the header value indicates when Amazon S3 is scheduled to delete the object copy. For example:

x-amz-restore: ongoing-request="false", expiry-date="Fri, 21 Dec 2012 00:00:00 GMT"

If the object restoration is in progress, the header returns the value ongoing-request="true".

For more information about archiving objects, see Transitioning Objects: General Considerations.

x-amz-server-side-encryption

The server-side encryption algorithm used when storing this object in Amazon S3 (for example, AES256, aws:kms, aws:kms:dsse).

Valid Values: AES256 | aws:kms | aws:kms:dsse

x-amz-server-side-encryption-aws-kms-key-id

If present, specifies the ID of the AWS Key Management Service (AWS KMS) symmetric encryption customer managed key that was used for the object.

x-amz-server-side-encryption-bucket-key-enabled

Indicates whether the object uses an S3 Bucket Key for server-side encryption with AWS Key Management Service (AWS KMS) keys (SSE-KMS).

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

If server-side encryption with a customer-provided encryption key was requested, the response will include this header confirming the encryption algorithm used.

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

If server-side encryption with a customer-provided encryption key was requested, the response will include this header to provide round-trip message integrity verification of the customer-provided encryption key.

x-amz-storage-class

Provides storage class information of the object. Amazon S3 returns this header for all objects except for S3 Standard storage class objects.

For more information, see Storage Classes.

Valid Values: STANDARD | REDUCED_REDUNDANCY | STANDARD_IA | ONEZONE_IA | INTELLIGENT_TIERING | GLACIER | DEEP_ARCHIVE | OUTPOSTS | GLACIER_IR | SNOW

x-amz-version-id

Version of the object.

x-amz-website-redirect-location

If the bucket is configured as a website, redirects requests for this object to another object in the same bucket or to an external URL. Amazon S3 stores the value of this header in the object metadata.

Errors

NoSuchKey

The specified key does not exist.

HTTP Status Code: 400

Examples

Sample Request

The following request returns the metadata of an object.

            HEAD /my-image.jpg HTTP/1.1
            Host: bucket.s3.<Region>.amazonaws.com
            Date: Wed, 28 Oct 2009 22:32:00 GMT
            Authorization: AWS AKIAIOSFODNN7EXAMPLE:02236Q3V0RonhpaBX5sCYVf1bNRuU=
         

Sample Response

This example illustrates one usage of HeadObject.

            HTTP/1.1 200 OK
            x-amz-id-2: ef8yU9AS1ed4OpIszj7UDNEHGran
            x-amz-request-id: 318BC8BC143432E5
            x-amz-version-id: 3HL4kqtJlcpXroDTDmjVBH40Nrjfkd
            Date: Wed, 28 Oct 2009 22:32:00 GMT
            Last-Modified: Sun, 1 Jan 2006 12:00:00 GMT
            ETag: "fba9dede5f27731c9771645a39863328"
            Content-Length: 434234
            Content-Type: text/plain
            Connection: close
            Server: AmazonS3
         

Sample Response: With an expiration tag

If the object is scheduled to expire according to a lifecycle configuration set on the bucket, the response returns the x-amz-expiration tag with information about when Amazon S3 will delete the object. For more information, see Transitioning Objects: General Considerations.

            HTTP/1.1 200 OK
            x-amz-id-2: azQRZtQJ2m1P8R+TIsG9h0VuC/DmiSJmjXUMq7snk+LKSJeurtmfzSlGhR46GzSJ
            x-amz-request-id: 0EFF61CCE3F24A26
            Date: Mon, 17 Dec 2012 02:26:39 GMT
            Last-Modified: Mon, 17 Dec 2012 02:14:10 GMT
            x-amz-expiration: expiry-date="Fri, 21 Dec 2012 00:00:00 GMT", rule-id="Rule for testfile.txt"
            ETag: "54b0c58c7ce9f2a8b551351102ee0938"
            Accept-Ranges: bytes
            Content-Type: text/plain
            Content-Length: 14
            Server: AmazonS3
         

Sample Request: Getting metadata from a specified version of an object

The following request returns the metadata of the specified version of an object.

            HEAD /my-image.jpg?versionId=3HL4kqCxf3vjVBH40Nrjfkd HTTP/1.1
            Host: bucket.s3.<Region>.amazonaws.com
            Date: Wed, 28 Oct 2009 22:32:00 GMT
            Authorization: AWS AKIAIOSFODNN7EXAMPLE:02236Q3V0WpaBX5sCYVf1bNRuU=
         

Sample Response: To a versioned HEAD request

This example illustrates one usage of HeadObject.

            HTTP/1.1 200 OK
            x-amz-id-2: eftixk72aD6Ap51TnqcoF8epIszj7UDNEHGran
            x-amz-request-id: 318BC8BC143432E5
            x-amz-version-id: 3HL4kqtJlcpXrof3vjVBH40Nrjfkd
            Date: Wed, 28 Oct 2009 22:32:00 GMT
            Last-Modified: Sun, 1 Jan 2006 12:00:00 GMT
            ETag: "fba9dede5f27731c9771645a39863328"
            Content-Length: 434234
            Content-Type: text/plain
            Connection: close
            Server: AmazonS3
         

Sample Request: For an S3 Glacier object

For an archived object, the x-amz-restore header provides the date when the restored copy expires, as shown in the following response. Even if the object is stored in S3 Glacier, all object metadata is still available.

            HEAD /my-image.jpg HTTP/1.1
            Host: bucket.s3.<Region>.amazonaws.com
            Date: 13 Nov 2012 00:28:38 GMT
            Authorization: AWS AKIAIOSFODNN7EXAMPLE:02236Q3V0RonhpaBX5sCYVf1bNRuU=
         

Sample Response: S3 Glacier object

If the object is already restored, the x-amz-restore header provides the date when the restored copy will expire, as shown in the following response.

            HTTP/1.1 200 OK
            x-amz-id-2: FSVaTMjrmBp3Izs1NnwBZeu7M19iI8UbxMbi0A8AirHANJBo+hEftBuiESACOMJp
            x-amz-request-id: E5CEFCB143EB505A
            Date: Tue, 13 Nov 2012 00:28:38 GMT
            Last-Modified: Mon, 15 Oct 2012 21:58:07 GMT
            x-amz-restore: ongoing-request="false", expiry-date="Wed, 07 Nov 2012 00:00:00 GMT"
            ETag: "1accb31fcf202eba0c0f41fa2f09b4d7"
            Accept-Ranges: bytes
            Content-Type: binary/octet-stream
            Content-Length: 300
            Server: AmazonS3
         

Sample Response: In-progress restoration

If the restoration is in progress, the x-amz-restore header returns a message accordingly.

            HTTP/1.1 200 OK
            x-amz-id-2: b+V2mDiMHTdy1myoUBpctvmJl95H9U/OSUm/jRtHxjh0+pCk5SvByL4xu2TDv4GM
            x-amz-request-id: E2E7B6AEE4E9BD2B
            Date: Tue, 13 Nov 2012 00:43:32 GMT
            Last-Modified: Sat, 20 Oct 2012 21:28:27 GMT
            x-amz-restore: ongoing-request="true"
            ETag: "1accb31fcf202eba0c0f41fa2f09b4d7"
            Accept-Ranges: bytes
            Content-Type: binary/octet-stream
            Content-Length: 300
            Server: AmazonS3
         

Sample Response: Object archived using S3 Intelligent-Tiering

If an object is stored using the S3 Intelligent-Tiering storage class and is currently in one of the archive tiers, then this action shows the current tier using the x-amz-archive-status header.

            HTTP/1.1 200 OK
            x-amz-id-2: FSVaTMjrmBp3Izs1NnwBZeu7M19iI8UbxMbi0A8AirHANJBo+hEftBuiESACOMJp
            x-amz-request-id: E5CEFCB143EB505A
            Date: Fri, 13 Nov 2020 00:28:38 GMT
            Last-Modified: Mon, 15 Oct 2012 21:58:07 GMT
            ETag: "1accb31fcf202eba0c0f41fa2f09b4d7"
	    x-amz-storage-class: 'INTELLIGENT_TIERING'
            x-amz-archive-status: 'ARCHIVE_ACCESS'
            Accept-Ranges: bytes
            Content-Type: binary/octet-stream
            Content-Length: 300
            Server: AmazonS3
         

Sample Response: Object archived using S3 Intelligent-Tiering with restore in progress

If an object is stored using the S3 Intelligent-Tiering storage class and is currently in the process of being restored from one of the archive tiers, then this action shows the current tier using the x-amz-archive-status header and the current restore status using the x-amz-restore header.

            HTTP/1.1 200 OK
            x-amz-id-2: FSVaTMjrmBp3Izs1NnwBZeu7M19iI8UbxMbi0A8AirHANJBo+hEftBuiESACOMJp
            x-amz-request-id: E5CEFCB143EB505A
            Date: Fri, 13 Nov 2020 00:28:38 GMT
            Last-Modified: Mon, 15 Oct 2012 21:58:07 GMT
            ETag: "1accb31fcf202eba0c0f41fa2f09b4d7"
	    x-amz-storage-class: 'INTELLIGENT_TIERING'
	    x-amz-archive-status: 'ARCHIVE_ACCESS'
	    x-amz-restore: 'ongoing-request="true"'
            x-amz-restore-request-date: 'Fri, 13 Nov 2020 00:20:00 GMT'
            Accept-Ranges: bytes
            Content-Type: binary/octet-stream
            Content-Length: 300
            Server: AmazonS3
         

See Also

For more information about using this API in one of the language-specific AWS SDKs, see the following:

• AWS Command Line Interface

• AWS SDK for .NET

• AWS SDK for C++

• AWS SDK for Go

• AWS SDK for Java V2

• AWS SDK for JavaScript

• AWS SDK for PHP V3

• AWS SDK for Python

• AWS SDK for Ruby V3