doc-exports/docs/obs/s3api/en-us_topic_0125560379.html

HEAD Object

You can use this operation to view an object's metadata, as long as you have READ permission for the object.

This operation makes server-side encryption available.

Versioning

By default, the metadata of the object of the latest version is obtained. If the version ID of the object is a deletion mark, 404 is returned. You can specify versionId to obtain the metadata of an object of the desired version.

Request Syntax

HEAD /ObjectName HTTP/1.1 
 User-Agent: agent
 Host: bucketname.obs.example.com 
 Accept: */*
 Date: date 
 Authorization: authorization

Request Parameters

Table 1 describes the request parameter.

Table 1 Request parameter

Parameter	Description	Remarks
versionId	Indicates the version ID of an object. Type: String	Optional

Request Headers

This request uses common headers. For details about common request headers, see section Common Request Headers.

If you want to obtain CORS configuration information, you must use the headers in Table 2.

Table 2 Request headers of CORS configuration

Header	Description	Remarks
Origin	Indicates an origin specified by a pre-request. Generally, it is a domain name. Type: String	Mandatory
Access-Control-Request-Headers	Indicates the HTTP headers of a request. The request can use multiple HTTP headers. Type: String	Optional
x-amz-server-side-encryption-customer-algorithm	Indicates a decryption algorithm. The header is used in SSE-C mode. Type: string Example: x-amz-server-side-encryption-customer-algorithm:AES256 Constraints: This header must be used together with x-amz-server-side-encryption-customer-key and x-amz-server-side-encryption-customer-key-MD5.	No. This header is mandatory when SSE-C is used.
x-amz-server-side-encryption-customer-key	Indicates a key used to decrypt objects. The header is used in SSE-C mode. Type: string Example: x-amz-server-side-encryption-customer-key:K7QkYpBkM5+hcs27fsNkUnNVaobncnLht/rCB2o/9Cw= Constraints: This header is a base64-encoded 256-bit or 512-bit key and must be used together with x-amz-server-side-encryption-customer-algorithm and x-amz-server-side-encryption-customer-key-MD5.	No. This header is mandatory when SSE-C is used.
x-amz-server-side-encryption-customer-key-MD5	Indicates the MD5 value of a key used to decrypt objects. The header is used in SSE-C mode. The MD5 value is used to check whether any error occurs during the transmission of the key. Type: string Example: x-amz-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ== Constraints: This header is a base64-encoded 128-bit MD5 value and must be used together with x-amz-server-side-encryption-customer-algorithm and x-amz-server-side-encryption-customer-key.	No. This header is mandatory when SSE-C is used.
x-amz-security-token	Header field used to identify the request of a federated user. When the federal authentication function is enabled, users sending such requests are identified as federated users. Type: string	Optional. This parameter must be carried in the request sent by federated users.

Request Elements

This request involves no elements.

Response Syntax

HTTP/1.1 status_code 
 Server: Server Name 
 x-amz-request-id: request id 
 x-amz-id-2: id 
 x-reserved: amazon, aws and amazon web services are trademarks or registered trademarks of Amazon Technologies, Inc 
 Accept-Ranges: bytes
 Content-Type: type 
 Date: date 
 Content-Length: length 
 Etag: etag 
 Last-Modified: time

Response Headers

This response uses common headers. For details about common response headers, see section Common Response Headers.

This response can also include an optional header. Table 3 describes the header.

Table 3 Optional response header

Header	Description
x-amz-expiration	This header is included in the response if the object expiration is configured. This header includes expiry-date and rule-id key value pairs to provide object expiration information. Type: String
x-amz-website-redirect-location	When a bucket is configured as a website, you can set this metadata for the object so that the website endpoint will evaluate the request for the object as a 301 redirect to another object in the same bucket or an external URL. Type: String
x-amz-version-id	Indicates the version ID of an object. If an object has no version ID specified, this header is not returned. Valid values: String Default: None
Access-Control-Allow-Origin	CORS is configured for buckets. If Origin in the request meets the CORS configuration requirements, Origin is included in the response. Type: String
Access-Control-Allow-Headers	CORS is configured for buckets. If headers in the request meet the CORS configuration requirements, headers are included in the response. Type: String
Access-Control-Max-Age	Indicates MaxAgeSeconds in the CORS configuration of a server when CORS is configured for buckets. Type: Integer
Access-Control-Allow-Methods	CORS is configured for buckets. If Access-Control-Request-Method in the request meets the CORS configuration requirements, methods in the rule are included in the response. Type: String Valid values: GET, PUT, HEAD, POST, and DELETE
Access-Control-Expose-Headers	Indicates ExposeHeader in the CORS configuration of a server when CORS is configured for buckets. Type: String
x-amz-server-side-encryption	This header is included in a response if SSE-KMS is used. Type: string Example: x-amz-server-side-encryption:aws:kms
x-amz-server-side-encryption-aws-kms-key-id	Indicates the master key ID. This header is included in a response if SSE-KMS is used. Example: x-amz-server-side-encryption-aws-kms-key-id:arn:aws:kms:sichuan:domainiddomainiddomainiddoma0001:key/4f1cd4de-ab64-4807-920a-47fc42e7f0d0
x-amz-server-side-encryption-customer-algorithm	Indicates a decryption algorithm. This header is included in a response if SSE-C is used. Type: string Example: x-amz-server-side-encryption-customer-algorithm:AES256
x-amz-server-side-encryption-customer-key-MD5	Indicates the MD5 value of a key used to decrypt objects. This header is included in a response if SSE-C is used. Type: string Example: x-amz-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ==
x-amz-storage-class	This header is returned when the storage class of an object is not Standard. Type: String Valid values: STANDARD_IA and GLACIER
x-amz-restore	The following provides examples of object restoration status: ongoing-request="true"indicates that the object is being restored. ongoing-request="false"indicates that the object has been restored. In expiry-date="Wed, 07 Nov 2012 00:00:00 GMT", expiry-date indicates the expiry date of the restored object. Type: String

Response elements

This response involves no elements.

Error Responses

No special error responses are returned. For details about error responses, see Table 1.

Sample Request

HEAD /test HTTP/1.1 
 User-Agent: Jakarta Commons-HttpClient/3.1 
 Host: bucketname.obs.example.com 
 Accept: */*
 Date: Sat, 03 Dec 2011 09:17:57 +0000 
 Authorization: AWS BF6C09F302931425E9A7:++6NkzwVhw4qccNfIqf4G2vMggg=

Sample Response

HTTP/1.1 200 OK  
 Server: OBS 
 x-amz-request-id: 001B21A61C6C0000013403373811529D 
 x-amz-id-2: MDAxQjIxQTYxQzZDMDAwMDAxMzQwMzM3MzgxMTUyOURBQUFBQUFBQWJiYmJiYmJi 
 x-reserved: amazon, aws and amazon web services are trademarks or registered trademarks of Amazon Technologies, Inc 
 Accept-Ranges: bytes
 ETag: "507e3fff69b69bf57d303e807448560b" 
 Last-Modified: Sat, 03 Dec 2011 08:47:50 GMT 
 Content-Length: 30 
 Content-Type: binary/octet-stream 
 Date: Sat, 03 Dec 2011 09:17:57 GMT  

Sample Request (Getting the Metadata of an Object with Version ID Specified)

HEAD /object?versionId=AAABQ4-glIvc0vycq3gAAAAVVURTRkha HTTP/1.1 
 User-Agent: Jakarta Commons-HttpClient/3.1 
 Host: bucketname.obs.example.com 
 Accept: */* 
 Date: Tue, 14 Jan 2014 07:22:17 +0000 
 Authorization: AWS C9590CEB8EC051BDEC9D:CTunmEJMuOBqUa4zfJNz6zxkjBE=

Sample Response (Getting the Metadata of an Object with Version ID Specified)

HTTP/1.1 200 OK 
 Server: OBS 
 x-amz-request-id: DCD2FC9CAB78000001438FA11E6CBB07 
 x-amz-id-2: SSfKQyh2Gr6ygerqHhJLZ6rxPiv+ucjWabr48RssNJMWmGyKh9gDdXC0jvo1JmFs 
 x-reserved: amazon, aws and amazon web services are trademarks or registered trademarks of Amazon Technologies, Inc 
 Accept-Ranges: bytes 
 ETag: "ba1f2511fc30423bdbb183fe33f3dd0f" 
 Last-Modified: Tue, 14 Jan 2014 07:21:42 GMT 
 Content-Length: 4 
 x-amz-version-id: AAABQ4-glIvc0vycq3gAAAAVVURTRkha 
 Content-Type: binary/octet-stream 
 Date: Tue, 14 Jan 2014 07:22:17 GMT

Sample Request (Getting Object Metadata and CORS Configuration when CORS is properly configured)

HEAD /object HTTP/1.1
User-Agent: curl/7.19.0 (x86_64-suse-linux-gnu) libcurl/7.19.0 OpenSSL/0.9.8{ zlib/1.2.3 libidn/1.10
Host: bucketname.obs.example.com
Accept: */*
Date: Tue, 28 Apr 2015 14:03:45 +0000
Authorization: AWS D13E0C94E722DD69423C:YcuaA/lJkmWn8AqjfWvIodNJ/yM=
Origin:www.example.com
Access-Control-Request-Headers:AllowedHeader_1

Sample Response (Getting Object Metadata and CORS Configuration when CORS is properly configured)

HTTP/1.1 200 OK
x-amz-request-id: D168613B12D6EE5744A69C524D3AA876
x-amz-id-2: 35Sas+J9yUY4xz3PrL0O938UKDg+Dc8EfSw0m9LtfoqB7s0wiMc44TOGguSLNyOv
x-reserved: amazon, aws and amazon web services are trademarks or registered trademarks of Amazon Technologies, Inc
Access-Control-Allow-Origin: www.example.com
Access-Control-Allow-Methods: POST,GET,HEAD,PUT,DELETE
Access-Control-Allow-Headers: AllowedHeader_1
Access-Control-Max-Age: 100
Access-Control-Expose-Headers: ExposeHeader_1
Accept-Ranges: bytes
ETag: "6bcb16084a88ae550811429c0c1e8bc7"
Last-Modified: Tue, 28 Apr 2015 13:38:05 GMT
Content-Length: 264
Content-Type: binary/octet-stream
Date: Tue, 28 Apr 2015 14:03:45 GMT

Parent topic: Operations on Objects