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.
SSE-C headers are required if you want to obtain the metadata of an object encrypted using SSE-C. For details, see Table 2.
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
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HEAD /ObjectName HTTP/1.1 Host: bucketname.obs.region.myhuaweicloud.com Date: date Authorization: authorization |
Request Parameters
Table 1 describes the request parameters.
Request Headers
This request uses common headers. For details, see Table 3.
In addition, the request can use additional headers shown in Table 2.
Header |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
Origin |
String |
No |
Explanation: Origin specified in a preflight request that makes a cross-domain request, usually as a domain name. Restrictions: You can enter multiple origins, with one separated from another using a line break. Each origin can contain at most one wildcard character (*). Value range: The value that complies with the CORS Default value: None |
Access-Control-Request-Headers |
String |
No |
Explanation: Indicates the HTTP headers that are allowed in a request. The request can use multiple HTTP headers. Restrictions: You can enter multiple allowed headers, with one separated from another using a line break. Each header can contain at most one wildcard character (*). Spaces, ampersands (&), colons (:), less-than signs (<), and full-width characters are not allowed. Value range: The value that complies with the CORS Default value: None |
x-obs-server-side-encryption-customer-algorithm |
String |
No. This header is required when SSE-C is used. |
Explanation: Indicates the decryption algorithm used when SSE-C is used. Example: x-obs-server-side-encryption-customer-algorithm:AES256 Restrictions: This header must be used together with x-obs-server-side-encryption-customer-key and x-obs-server-side-encryption-customer-key-MD5. Value range: AES256 Default value: None |
x-obs-server-side-encryption-customer-key |
String |
No. This header is required when SSE-C is used. |
Explanation: Indicates the decryption key used when SSE-C is used. Example: x-obs-server-side-encryption-customer-key:K7QkYpBkM5+hca27fsNkUnNVaobncnLht/rCB2o/9Cw= Restrictions: This header is a Base64-encoded 256-bit key and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key-MD5. Value range: None Default value: None |
x-obs-server-side-encryption-customer-key-MD5 |
String |
No. This header is required when SSE-C is used. |
Explanation: Indicates the MD5 value of the decryption key when SSE-C is used. The MD5 value is used to check whether any error occurs during the transmission of the key. Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ== Restrictions: This header is a Base64-encoded 128-bit MD5 value and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key. Value range: Base64-encoded MD5 value of the key ID. Default value: None |
Request Elements
This request involves no elements.
Response Syntax
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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.
Header |
Type |
Description |
---|---|---|
x-obs-expiration |
String |
Explanation: Expiration details Restrictions: None Value range: 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. Default value: None |
x-obs-website-redirect-location |
String |
Explanation: Indicates where an object request is redirected. If the bucket that contains the object is configured with Website settings, this parameter can be set in the object metadata so that the request for the object can be redirected to another object in the same bucket or an external URL after the website returns a 301 redirect response. To another object in the same bucket: WebsiteRedirectLocation:/anotherPage.html To an external URL: WebsiteRedirectLocation:http://www.example.com/ OBS obtains the specified value from the header and stores it in the object metadata WebsiteRedirectLocation. Restrictions:
Default value: None |
x-obs-version-id |
String |
Explanation: Version ID of the object. If the object has no version number specified, the response does not contain this header. Restrictions: The value must contain 32 characters. Value range: None Default value: None |
Access-Control-Allow-Origin |
String |
Explanation: Returned if the request origin meets the CORS configured on the server. Restrictions: None Value range: The value that complies with the CORS Default value: None |
Access-Control-Allow-Headers |
String |
Explanation: Returned if the request headers meet the CORS configured on the server. Restrictions: At most one asterisk (*) is allowed. Spaces, ampersands (&), colons (:), less-than signs (<), and full-width characters are not allowed. Value range: The value that complies with the CORS Default value: None |
Access-Control-Max-Age |
Integer |
Explanation: MaxAgeSeconds in the CORS rules of the bucket. It specifies the time your client can cache the response for a cross-origin request. Restrictions: Each CORS rule can contain at most one MaxAgeSeconds. Value range: An integer greater than or equal to 0, in seconds Default value: 3000 |
Access-Control-Allow-Methods |
String |
Explanation: 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. Value range:
|
Access-Control-Expose-Headers |
String |
Explanation: ExposeHeader in the CORS rules of the bucket. It specifies additional headers allowed in the response by a CORS rule, which are used to provide extra information to clients. By default, a browser can access only headers Content-Length and Content-Type. If the browser needs to access other headers, you need to configure them as additional headers. Restrictions: Spaces, asterisks (*), ampersands (&), colons (:), less-than signs (<), and full-width characters are not allowed. Value range: None Default value: None |
x-obs-server-side-encryption |
String |
Explanation: The encryption method used by the server. Example: x-obs-server-side-encryption:kms Restrictions: This header is included in a response if SSE-KMS is used. Value range:
Default value: None |
x-obs-server-side-encryption-kms-key-id |
String |
Explanation: ID of a specified key used for SSE-KMS encryption. For details about how to obtain a key ID, see Viewing a Key. Restrictions: This header can only be used when you specify kms for the x-obs-server-side-encryption header. Default value: If you specify kms for encryption but do not specify a key ID, the default master key will be used. If there is not a default master key, OBS will create one and use it. |
x-obs-server-side-encryption-customer-algorithm |
String |
Explanation: Indicates a decryption algorithm. This header is included in a response if SSE-C is used. Example: x-obs-server-side-encryption-customer-algorithm:AES256 Restrictions: None Value range: AES256 Default value: None |
x-obs-server-side-encryption-customer-key-MD5 |
String |
Explanation: Indicates the MD5 value of a key used to decrypt objects. This header is included in a response if SSE-C is used. Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ== Restrictions: Base64-encoded MD5 value of the key, for example, 4XvB3tbNTN+tIEVa0/fGaQ==. Value range: Base64-encoded MD5 value of the key ID. Default value: None |
x-obs-storage-class |
String |
Explanation: Storage class of an object. Restrictions: This header is returned only when the storage class of an object is not Standard. Value range:
Default value: None |
x-obs-restore |
String |
Explanation: Restore status of an object. For example, ongoing-request="true" indicates that the object is being restored. ongoing-request="false", expiry-date="Wed, 7 Nov 2012 00:00:00 GMT" indicates that the object has been restored, where expiry-date indicates when the restored object expires. Restrictions: This header is returned only when an Archive or Deep Archive object is being restored or has been restored. Value range: None Default value: None |
x-obs-object-type |
String |
Explanation: Object type Restrictions: This header is returned only when the object is not a Normal object. Value range: Appendable Default value: None |
x-obs-next-append-position |
Integer |
Explanation: Indicates the position that should be provided in the next request. Restrictions: This header is returned only when the object is an Appendable object. Value range: None Default value: None |
x-obs-uploadId |
String |
Explanation: Indicates the ID of a multipart task. Restrictions: This header is returned only when the object is created from a multipart upload. Value range: None Default value: None |
x-obs-object-lock-mode |
String |
Explanation: WORM mode applied to the object. Example: x-obs-object-lock-mode:COMPLIANCE Restrictions:
Value range: Currently, only COMPLIANCE (compliance mode) is supported. Default value: None |
x-obs-object-lock-retain-until-date |
String |
Explanation: When an object lock expires. Example: x-obs-object-lock-retain-until-date:2015-07-01T04:11:15Z Restrictions:
Value range: The value must be later than the current time. Default value: None |
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
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HEAD /object1 HTTP/1.1 User-Agent: curl/7.29.0 Host: examplebucket.obs.region.myhuaweicloud.com Accept: */* Date: WED, 01 Jul 2015 04:19:25 GMT Authorization: OBS H4IPJX0TQTHTHEBQQCEC:/cARjk81l2iExMfQqn6iT3qEZ74= |
Sample Response
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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 |
Sample Request: Obtaining Object Metadata from a Versioning-enabled Bucket
HEAD /object1?versionId=G001118A49821905FFFFD28739D419DA HTTP/1.1 Authorization: OBS H4IPJX0TQTHTHEBQQCEC:iqSPeUBl66PwXDApxjRKk6hlcN4= User-Agent: curl/7.29.0 Host: examplebucket.obs.region.myhuaweicloud.com Date: WED, 01 Jul 2015 02:37:22 GMT Content-Type: application/xml
Sample Response: Obtaining Object Metadata from a Versioning-enabled Bucket
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCShLiL70qeT0g5qpMquCeztsnr1jJmRs Accept-Ranges: bytes x-obs-request-id: 0000018A4986DDCDD24538ACF6B54255 Server: OBS ETag: \ x-obs-tagging-count: 0 Last-Modified: Thu, 31 Aug 2013 02:52:57 GMT Content-Length: 0 Date: WED, 01 Jul 2015 02:37:22 GMT Content-Type: text/plain x-obs-version-id: G001118A49821905FFFFD28739D419DA
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