head_object¶

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-zone-id.region-code.amazonaws.com. Path-style requests are not supported. Directory bucket names must be unique in the chosen Zone (Availability Zone or Local Zone). Bucket names must follow the format bucket-base-name--zone-id--x-s3 (for example, amzn-s3-demo-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 for general purpose buckets, you must provide the alias of the access point in place of the bucket name or specify the access point ARN. When you use this action with an access point for directory buckets, you must provide the access point name in place of the bucket name. 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.

S3 on Outposts - When you use this action with 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, the destination bucket must be the Outposts access point ARN or the access point alias. For more information about S3 on Outposts, see What is S3 on Outposts? in the Amazon S3 User Guide.

To retrieve the checksum, this parameter must be enabled.

General purpose buckets - If you enable checksum mode and the object is uploaded with a checksum and encrypted with an Key Management Service (KMS) key, you must have permission to use the kms:Decrypt action to retrieve the checksum.

Directory buckets - If you enable ChecksumMode and the object is encrypted with Amazon Web Services Key Management Service (Amazon Web Services KMS), you must also have the kms:GenerateDataKey and kms:Decrypt permissions in IAM identity-based policies and KMS key policies for the KMS key to retrieve the checksum of the object.

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).

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

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.

For more information about conditional requests, see RFC 7232.

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

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.

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

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.

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

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.

For more information about conditional requests, see RFC 7232.

The object key.

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.

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.

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 S3 bucket has Requester Pays enabled, the requester will pay for the corresponding charges. For information about downloading objects from Requester Pays buckets, see Downloading Objects in Requester Pays Buckets in the Amazon S3 User Guide.

Sets the Cache-Control header of the response.

Sets the Content-Disposition header of the response.

Sets the Content-Encoding header of the response.

Sets the Content-Language header of the response.

Sets the Content-Type header of the response.

Sets the Expires header of the response.

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

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.

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.

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

Indicates that a range of bytes was specified.

The archive state of the head object.

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

Specifies caching behavior along the request/reply chain.

The Base64 encoded, 32-bit CRC32 checksum of the object. This checksum is only present if the checksum was uploaded with the object. When you use an API operation on an object that was uploaded using multipart uploads, this value may not be a direct checksum value of the full object. Instead, it's a calculation based on the checksum values of each individual part. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 32-bit CRC32C checksum of the object. This checksum is only present if the checksum was uploaded with the object. When you use an API operation on an object that was uploaded using multipart uploads, this value may not be a direct checksum value of the full object. Instead, it's a calculation based on the checksum values of each individual part. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 64-bit CRC64NVME checksum of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 128-bit MD5 digest of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 160-bit SHA1 digest of the object. This checksum is only present if the checksum was uploaded with the object. When you use the API operation on an object that was uploaded using multipart uploads, this value may not be a direct checksum value of the full object. Instead, it's a calculation based on the checksum values of each individual part. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 256-bit SHA256 digest of the object. This checksum is only present if the checksum was uploaded with the object. When you use an API operation on an object that was uploaded using multipart uploads, this value may not be a direct checksum value of the full object. Instead, it's a calculation based on the checksum values of each individual part. For more information about how checksums are calculated with multipart uploads, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 512-bit SHA512 digest of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

The checksum type, which determines how part-level checksums are combined to create an object-level checksum for multipart objects. You can use this header response to verify that the checksum type that is received is the same checksum type that was specified in CreateMultipartUpload request. For more information, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 128-bit XXHASH128 checksum of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 64-bit XXHASH3 checksum of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

The Base64 encoded, 64-bit XXHASH64 checksum of the object. For more information, see Checking object integrity in the Amazon S3 User Guide.

Specifies presentational information for the object.

Indicates 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.

The language the content is in.

Size of the body in bytes.

The portion of the object returned in the response for a GET request.

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

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.

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

If the object expiration is configured (see PutBucketLifecycleConfiguration ), 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.

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

Date and time when the object was last modified.

A map of metadata to store with the object in S3.

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.

The event hold status for this object. This header is only returned if the requester has the s3:GetObjectRetention permission.

The event hold duration in days for this object. Only returned when the event hold is enabled.

The event hold duration in years for this object. Only returned when the event hold is enabled.

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.

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.

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

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.

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.

If present, indicates that the requester was successfully charged for the request. For more information, see Using Requester Pays buckets for storage transfers and usage in the Amazon Simple Storage Service user guide.

Metadata about the response that produced this output. Use this to recover the request identifiers a service's support team needs in order to investigate a call. Members of the metadata are individually optional.

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.

The server-side encryption algorithm used when you store this object in Amazon S3 or Amazon FSx.

If server-side encryption with a customer-provided encryption key was requested, the response will include this header to confirm the encryption algorithm that's used.

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

If present, indicates the ID of the KMS key that was used for object encryption.

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.

The number of tags, if any, on the object, when you have the relevant permission to read object tags.

You can use GetObjectTagging to retrieve the tag set associated with an object.

Version ID of the object.

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.