Querying Object Metadata

Functions

Users with the read permission on objects can perform the HeadObject operation to obtain metadata of objects. The object metadata is included in the response.

Versioning

By default, this operation returns the latest metadata of an object. If the object has a delete marker, status code 404 is returned. To obtain the object metadata of a specified version, the versionId parameter can be used to specify the desired version.

Request Syntax

    
         HEAD /ObjectName HTTP/1.1 
Host: bucketname.obs.region.example.com
Date: date
Authorization: authorization

Request Parameters

Table 1 describes the request parameters.

**Table 1** Request parameters
Parameter	Description	Mandatory
versionId	Object version ID Type: string	No

Request Headers

This request uses common headers. For details, see Table 3.

In addition, the request can use additional headers, as shown in Table 2.

**Table 2** Request headers
Header	Description	Mandatory
Origin	Origin of the cross-domain request specified by the pre-request. Generally, it is a domain name. Type: string	No
Access-Control-Request-Headers	Indicates the HTTP headers of a request. The request can use multiple HTTP headers. Type: string	No

Request Elements

This request involves no elements.

Response Syntax

    
         HTTP/1.1 status_code
Content-Type: type
Date: date
Content-Length: length
Etag: etag
Last-Modified: time

Response Headers

The response to the request uses common headers. For details, see Table 1.

In addition to the common response headers, the headers listed in Table 3 may be used.

**Table 3** Additional response headers
Header	Description
x-obs-expiration	When an object has its lifecycle rule, the object expiration time is subject to its lifecycle rule. This header field is use expiry-date to describe the object expiration date. If the lifecycle rule is configured only for the entire bucket not individual objects, the object expiration time is subject to the bucket lifecycle rule. This header field uses the expiry-date and rule-id to describe the detailed expiration information of objects. If no lifecycle rule is configured, this header field is not contained in the response. Type: string
x-obs-website-redirect-location	Indicates the redirected-to location. If the bucket is configured with website information, this parameter can be set for the object metadata 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-obs-version-id	Object version ID. If the object has no version number specified, the response does not contain this header. Type: string Default value: none
Access-Control-Allow-Origin	Indicates that the origin is included in the response if the origin in the request meets the CORS configuration requirements when CORS is configured for buckets. Type: string
Access-Control-Allow-Headers	Indicates that the headers are included in the response if headers in the request meet the CORS configuration requirements when CORS is configured for buckets. Type: string
Access-Control-Max-Age	Value of MaxAgeSeconds in the CORS configuration of the server when CORS is configured for buckets. Type: integer
Access-Control-Allow-Methods	Indicates that methods in the rule are included in the response if Access-Control-Request-Method in the request meets the CORS configuration requirements when CORS is configured for buckets. Type: string Value options: GET, PUT, HEAD, POST, DELETE
Access-Control-Expose-Headers	Value of ExposeHeader in the CORS configuration of a server when CORS is configured for buckets. Type: string
x-obs-object-type	If the object is not a normal one, this header field is returned. The value can be Appendable. Type: string
x-obs-next-append-position	This header field is returned when the object is an appendable object. Type: integer
x-obs-uploadId	This header is returned if the object is a combination of multiple parts. The header value indicates the ID of the corresponding multipart upload task. Type: string

Response Elements

This response contains no elements.

Error Responses

No special error responses are returned. For details about error responses, see Table 2.

Sample Request

    
         HEAD /object1 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 04:19:25 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:/cARjk81l2iExMfQqn6iT3qEZ74=

Sample Response

    
         HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 8DF400000163D3E4BB5905C41B6E65B6
Accept-Ranges: bytes
ETag: "3b46eaf02d3b6b1206078bb86a7b7013"
Last-Modified: WED, 01 Jul 2015 01:19:21 GMT
Content-Type: binary/octet-stream
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCSD3nAiTaBoeyt9oHp9vTYtXnLDmwV6D
Date: WED, 01 Jul 2015 04:19:21 GMT
Content-Length: 4572