Common Response Headers - Amazon Simple Storage Service
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Common Response Headers

The following table describes response headers that are common to most Amazon S3 responses.

Name Description
Content-Length

The length in bytes of the body in the response.

Type: String

Default: None

Content-Type

The MIME type of the content. For example, Content-Type: text/html; charset=utf-8.

Type: String

Default: None

Connection

A value that specifies whether the connection to the server is open or closed.

Type: Enum

Valid Values: open | close

Default: None

Date

The date and time that Amazon S3 responded; for example, Wed, 01 Mar 2006 12:00:00 GMT.

Type: String

Default: None

ETag

The entity tag (ETag) represents a specific version of the object. The ETag reflects changes only to the contents of an object, not its metadata. The ETag might or might not be an MD5 digest of the object data. Whether or not it is depends on how the object was created and how it is encrypted, as follows:

  • Objects created through the Amazon Web Services Management Console or by the PUT Object, POST Object, or Copy operation:

    • Objects that are plaintext or encrypted by server-side encryption with Amazon S3 managed keys (SSE-S3) have ETags that are an MD5 digest of their data.

    • Objects encrypted by server-side encryption with customer-provided keys (SSE-C) or Amazon Key Management Service (Amazon KMS) keys (SSE-KMS) have ETags that are not an MD5 digest of their object data.

  • Objects created by either the Multipart Upload or Upload Part Copy operation have ETags that are not MD5 digests, regardless of the method of encryption.

Type: String

Server

The name of the server that created the response.

Type: String

Default: AmazonS3

x-amz-delete-marker

A value that specifies whether the object returned was (true) or was not (false) a delete marker.

Type: Boolean

Valid Values: true | false

Default: false

x-amz-id-2

A special token that is used together with the x-amz-request-id header to help Amazon troubleshoot problems. For information about Amazon Web Services Support using these request IDs, see Troubleshooting Amazon S3.

Type: String

Default: None

x-amz-request-id

A value created by Amazon S3 that uniquely identifies the request. This value is used together with the x-amz-id-2 header to help Amazon troubleshoot problems. For information about Amazon Web Services Support using these request IDs, see Troubleshooting Amazon S3.

Type: String

Default: None

x-amz-server-side-encryption

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

Valid Values: AES256 | aws:kms

x-amz-version-id

The version of the object. When you enable versioning, Amazon S3 generates a random number for objects added to a bucket. The value is UTF-8 encoded and URL ready. When you PUT an object in a bucket where versioning has been suspended, the version ID is always null.

Type: String

Valid Values: null | any URL-ready, UTF-8 encoded string

Default: null