Help & Documentation>APIs>Cloud Object Storage>Object APIs>Basic Operations>HEAD Object

HEAD Object

Last updated: 2024-09-27 19:14:34

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Feature Overview

This API is used to determine whether an object exists and whether you have permission to access it. You can use this API to get the object metadata if you can access it. To call this API, you need to have permission to read the object, or the object is set to public-read (i.e., everyone can read it).


Authorization Description

In the authorization policy, set action to cos:HeadObject. View all actions.

Versioning

With versioning enabled, you can specify the versionId request parameter to get the metadata of an object of a specified version. If the version ID you specify corresponds to a delete marker, HTTP status code “404 (Not Found)” will be returned. If no version ID is specified, the metadata of the latest version will be returned.

Requests

Sample Request

HEAD /<ObjectKey> HTTP/1.1
Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
Date: GMT Date
Authorization: Auth String
Note
Host: <BucketName-APPID>.cos.<Region>.myqcloud.com, where <BucketName-APPID> is the bucket name with the APPID suffix, such as examplebucket-1250000000. You can refer to the Bucket Overview > Basic Information and Bucket Overview > Bucket Naming Convention documentation. <Region> represents the available regions for COS, which can be found in the Regions and Access Domain Names documentation.
Authorization: Auth String (For more information, see Request Signature.)

Request Parameters

Name
Description
Local Disk Types
Required
versionId
Specifies the version ID of the object if versioning is enabled; if this parameter is not specified, the latest version will be queried.
string
Not required

Request Header

In addition to common request headers, this API also supports the following request headers. For more information on the common request header, see Common Request Headers.
Name
Description
Local Disk Types
Required
If-Modified-Since
If the object is modified after the specified time, HTTP status code 200 (OK) will be returned. Otherwise, “304 (Not Modified)” will be returned.
string
Not required
If-Unmodified-Since
If the object is not modified after the specified time, HTTP status code 200 (OK) will be returned. Otherwise, “412 (Precondition Failed)” will be returned.
string
Not required
If-Match
If the ETag of the object is the same as the specified value, HTTP status code 200 (OK) will be returned. Otherwise, “412 (Precondition Failed)” will be returned.
string
Not required
If-None-Match
If the ETag of the object is different from the specified value, HTTP status code 200 (OK) will be returned. Otherwise, “304 (Not Modified)” will be returned.
string
Not required
Server-side Encryption-related Headers
If server-side encryption is used for the specified object and the encryption method is SSE-C, you will need to specify the headers related to server-side encryption to decrypt the object. For more information, see Server-side Encryption Headers.

Request Body

This API does not have a request body.

Response

Response Header

In addition to common response headers, this API also returns the following response headers. For more information on common response headers, see Common Response Headers.
Name
Description
Local Disk Types
Cache-Control
Cache directives as defined in RFC 2616, which will be returned only if it is contained in the object metadata.
string
Content-Disposition
Filename as defined in RFC 2616, which will be returned only if it is contained in the object metadata.
string
Content-Encoding
Encoding format as defined in RFC 2616, which will be returned only if it is contained in the object metadata.
string
Expires
Cache expiration time as defined in RFC 2616, which will be returned only if it is contained in the object metadata.
string
x-cos-meta-*
Includes user-defined metadata header suffixes and user-defined metadata information.
string
x-cos-storage-class
Object storage type, for enumeration values, please refer to the Storage Types documentation, such as MAZ_STANDARD, MAZ_STANDARD_IA, INTELLIGENT_TIERING, MAZ_INTELLIGENT_TIERING, STANDARD_IA, ARCHIVE, DEEP_ARCHIVE. This header will be returned only if the object is not STANDARD storage.
enum
x-cos-storage-tier
Specifies the access tier of INTELLIGENT TIERING objects. Valid values:
FREQUENT
INFREQUENT
ARCHIVE_ACCESS
DEEP_ARCHIVE_ACCESS
enum

Archived object−related headers

If the storage class of the object is ARCHIVE and POST Object restore has been called to restore it, the following response headers will be returned:
Name
Description
Local Disk Types
x-cos-restore
Indicates the current restoration operation status:
When the restoration operation is in progress, the value of this response header is ongoing-request="true"
When the object has been restored, this response header contains the time when COS will delete the temporary copy, for example: ongoing-request="false", expiry-date="Tue, 19 Nov 2019 16:00:00 GMT"
string
x-cos-restore-status
This response header will be returned if the restoration is ongoing, indicating the current restoration mode, the request time of the restoration and the expected completion time of restoration. tier="standard"; request-date="Mon, 18 Nov 2019 09:34:50 GMT";expect-restore-date="Fri, 27 Dec 2019 08:20:00 GMT". For more information on restoration modes, please see POST Object restore
Note:
Only archive-type objects support displaying the expected completion time of restoration. Deep archive objects do not support displaying the expected completion time of restoration.
string
Versioning-Related Headers
If the target object is from a versioning-enabled bucket, the following response header will be returned:
Name
Description
Local Disk Types
x-cos-version-id
Version ID of the object
string
Server-side Encryption-related Headers
If server-side encryption is used for the specified object, this API will return the server-side encryption headers. For more information, see Server-side Encryption Headers.
Bucket replication-related headers
If the object is the source or target object of bucket replication, the following response headers will be returned.
Name
Description
Type
x-cos-replication-status
Current replication status. The source object shows Pending, Failed, or Complete. The target object shows Replica.
string

Response Body

The response body of this API is empty.

Error Codes

This API returns common error responses and error codes. For more information, see Error Codes.

Examples

Example 1: simple use case (with versioning disabled)

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:17:36 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542656;1586549856&q-key-time=1586542656;1586549856&q-header-list=date;host&q-url-param-list=&q-signature=cde88925e00d1c90ba74985ca43b610bdf6b**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:17:36 GMT
ETag: "ee8de918d05640145b18f70f4c3aa602"
Last-Modified: Fri, 10 Apr 2020 18:17:25 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MGI4NDBfNjFjODJhMDlfMzY2NjVfMjNi****

Example 2: specifying search criteria through the request headers with HTTP status code 304 (Not Modified) returned

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Wed, 29 Jul 2020 06:51:49 GMT
If-None-Match: "ee8de918d05640145b18f70f4c3aa602"
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1596005509;1596012709&q-key-time=1596005509;1596012709&q-header-list=date;host;if-none-match&q-url-param-list=&q-signature=9d087f05c259ca271efe91fc780cdced75c6**
Connection: close

Response

HTTP/1.1 304 Not Modified
Content-Type: application/xml
Content-Length: 0
Connection: close
Date: Wed, 29 Jul 2020 06:51:49 GMT
Server: tencent-cos
x-cos-request-id: NWYyMTFjODVfZDNjODJhMDlfMWU1MWVfOTUy****
x-cos-trace-id: OGVmYzZiMmQzYjA2OWNhODk0NTRkMTBiOWVmMDAxODczNTBmNjMwZmQ0MTZkMjg0NjlkNTYyNmY4ZTRkZTk0NzJmZTI0ZmJhYTZmZjYyNmU5ZGNlZDI5YjkyODkwYjNhZjhlNGQ0MDY1ZGIxNDEwMWYwOTg1NDc4Mzg4MTE3****

Example 3: specifying search criteria through the request header with HTTP status code 412 (Precondition Failed) returned

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Wed, 29 Jul 2020 06:51:50 GMT
If-Match: "aa488bb80185a6be87f4a7b936a80752"
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1596005510;1596012710&q-key-time=1596005510;1596012710&q-header-list=date;host;if-match&q-url-param-list=&q-signature=38afe94fc61ca0b3aa763e00b23fd90ac23e**
Connection: close

Response

HTTP/1.1 412 Precondition Failed
Content-Type: application/xml
Content-Length: 0
Connection: close
Date: Wed, 29 Jul 2020 06:51:50 GMT
Server: tencent-cos
x-cos-request-id: NWYyMTFjODZfMzBjMDJhMDlfMmU3ZF9kYTE4****
x-cos-trace-id: OGVmYzZiMmQzYjA2OWNhODk0NTRkMTBiOWVmMDAxODczNTBmNjMwZmQ0MTZkMjg0NjlkNTYyNmY4ZTRkZTk0NzJmZTI0ZmJhYTZmZjYyNmU5ZGNlZDI5YjkyODkwYjNhZDRkOWFlZjczOWExNjZmY2RiNjhjNGIwZWQ3YjYw****

Example 4: using server-side encryption SSE-COS

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:18:19 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542699;1586549899&q-key-time=1586542699;1586549899&q-header-list=date;host&q-url-param-list=&q-signature=6a6d4dd5b5a9e6379f300715985bfb60b947**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:18:19 GMT
ETag: "ee8de918d05640145b18f70f4c3aa602"
Last-Modified: Fri, 10 Apr 2020 18:18:08 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MGI4NmJfNmRjMDJhMDlfZGQwNl8xZmE4****
x-cos-server-side-encryption: AES256

Example 5: using server-side encryption SSE-KMS

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:18:30 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542710;1586549910&q-key-time=1586542710;1586549910&q-header-list=date;host&q-url-param-list=&q-signature=7c8a1c93b9701e653c2ab00419f976397d00**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:18:30 GMT
ETag: "00ca268468481b847fc2d8a9bd84578d"
Last-Modified: Fri, 10 Apr 2020 18:18:19 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MGI4NzZfN2FjODJhMDlfMjU3N18xYTEz****
x-cos-server-side-encryption: cos/kms
x-cos-server-side-encryption-cos-kms-key-id: 48ba38aa-26c5-11ea-855c-52540085****


Example 6: using server-side encryption SSE-C

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:18:41 GMT
x-cos-server-side-encryption-customer-algorithm: AES256
x-cos-server-side-encryption-customer-key: MDEyMzQ1Njc4OUFCQ0RFRjAxMjM0NTY3ODlBQkNE****
x-cos-server-side-encryption-customer-key-MD5: U5L61r7jcwdNvT7frmUG****
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542721;1586549921&q-key-time=1586542721;1586549921&q-header-list=date;host;x-cos-server-side-encryption-customer-algorithm;x-cos-server-side-encryption-customer-key;x-cos-server-side-encryption-customer-key-md5&q-url-param-list=&q-signature=99ad258fc295f43feb0546bb2346c8269dc5**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:18:41 GMT
ETag: "582d9105f71525f3c161984bc005efb5"
Last-Modified: Fri, 10 Apr 2020 18:18:31 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MGI4ODFfN2NiODJhMDlfMmFmYTVfMWRh****
x-cos-server-side-encryption-customer-algorithm: AES256
x-cos-server-side-encryption-customer-key-MD5: U5L61r7jcwdNvT7frmUG****

Example 7: requesting the latest version of an object (with versioning enabled)

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:19:15 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542755;1586549955&q-key-time=1586542755;1586549955&q-header-list=date;host&q-url-param-list=&q-signature=7909dc19780873dfaa51c8b238254098ca1a**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 26
Connection: close
Date: Fri, 10 Apr 2020 18:19:15 GMT
ETag: "22e024392de860289f0baa7d6cf8a549"
Last-Modified: Fri, 10 Apr 2020 18:19:04 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 11596229263574363878
x-cos-request-id: NWU5MGI4YTNfZDZjODJhMDlfYmU0MV8xM2Y5****
x-cos-version-id: MTg0NDUxNTc1MzA5NjQ2ODI5MTg

Example 8: requesting a specific version of an object (with versioning enabled)

Requests

HEAD /exampleobject?versionId=MTg0NDUxNTc1MzA5NzU4ODg1Mjg HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 10 Apr 2020 18:19:04 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1586542744;1586549944&q-key-time=1586542744;1586549944&q-header-list=date;host&q-url-param-list=versionid&q-signature=1307acd3e8649087c738ecca452a54fa5a79**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:19:04 GMT
ETag: "ee8de918d05640145b18f70f4c3aa602"
Last-Modified: Fri, 10 Apr 2020 18:18:53 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MGI4OThfN2RiNDBiMDlfMTk1MTBfMWZj****
x-cos-version-id: MTg0NDUxNTc1MzA5NzU4ODg1Mjg

Example 9: requesting an archived object that is being restored

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Fri, 27 Dec 2019 08:19:35 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1577434775;1577441975&q-key-time=1577434775;1577441975&q-header-list=date;host&q-url-param-list=&q-signature=72408a09a5fc00d77d389559a0cfa5c98e31**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 13
Connection: close
Date: Fri, 27 Dec 2019 08:19:35 GMT
ETag: "b62e10bcab55a88240bd9c436cffdcf9"
Last-Modified: Fri, 27 Dec 2019 08:19:23 GMT
Server: tencent-cos
x-cos-request-id: NWUwNWJlOTdfN2VjODJhMDlfOGI1N18yYjYz****
x-cos-restore: ongoing-request="true"
x-cos-restore-status: tier="expedited"; request-date="Fri, 27 Dec 2019 08:19:29 GMT"
x-cos-storage-class: ARCHIVE

Example 10: requesting an archived object which has been restored

Requests

HEAD /exampleobject HTTP/1.1
Host: examplebucket-1250000000.cos.ap-beijing.myqcloud.com
Date: Thu, 02 Jan 2020 18:09:51 GMT
Authorization: q-sign-algorithm=sha1&q-ak=AKID8A0fBVtYFrNm02oY1g1JQQF0c3JO**&q-sign-time=1577988591;1577995791&q-key-time=1577988591;1577995791&q-header-list=date;host&q-url-param-list=&q-signature=ff23b3a44945f019916450add646e963c29b**
Connection: close

Response

HTTP/1.1 200 OK
Content-Type: image/jpeg
Content-Length: 16
Connection: close
Date: Fri, 10 Apr 2020 18:17:36 GMT
ETag: "ee8de918d05640145b18f70f4c3aa602"
Last-Modified: Fri, 10 Apr 2020 18:17:25 GMT
Server: tencent-cos
x-cos-hash-crc64ecma: 16749565679157681890
x-cos-request-id: NWU5MWRiZjFfMmViMDJhMDlfNjIwOF8zNTU0****
x-cos-restore: ongoing-request="false", expiry-date="Mon, 13 Apr 2020 16:00:00 GMT"
x-cos-storage-class: ARCHIVE

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