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Querying object metadata

Last updated: 2023-09-13 11:04:14

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Feature Overview

This document provides an overview of APIs and SDK code samples for querying object metadata.
API
Operation
Description
Querying object metadata
Queries the metadata of an object

Querying object metadata

Note

This API is used to query object metadata.

Method prototype

head_object(Bucket, Key, **kwargs)

Sample Request

# -*- coding=utf-8
from qcloud_cos import CosConfig
from qcloud_cos import CosS3Client
import sys
import os
import logging

# Under normal circumstances, use the INFO log level. To locate issues, change it to DEBUG, and the SDK will print communication information with the server.
logging.basicConfig(level=logging.INFO, stream=sys.stdout)

# 1. Set user properties, including secret_id, secret_key, region, etc. Appid has been removed from CosConfig, please include Appid in the Bucket parameter. Bucket is composed of BucketName-Appid.
secret_id = os.environ['COS_SECRET_ID']     # User <1>SecretId</1>. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For more information on how to obtain a sub-account key, visit https://cloud.tencent.com/document/product/598/37140.
secret_key = os.environ['COS_SECRET_KEY']   # User <1>SecretKey</1>. We recommend that you use a sub-account key and follow the principle of least privilege to reduce risks. For more information on how to obtain a sub-account key, visit https://cloud.tencent.com/document/product/598/37140.
region = 'ap-beijing'      # Replace it with the actual region, which can be viewed in the console at https://console.cloud.tencent.com/cos5/bucket.
                           For a list of all regions supported by COS, visit https://cloud.tencent.com/document/product/436/6224
token = None               # Token is required for temporary keys but not permanent keys. For more information about how to generate and use a temporary key, see https://cloud.tencent.com/document/product/436/14048.
scheme = 'https'           # Specify whether to use HTTP or HTTPS protocol to access COS. This is optional and is https by default.

config = CosConfig(Region=region, SecretId=secret_id, SecretKey=secret_key, Token=token, Scheme=scheme)
client = CosS3Client(config)

response = client.head_object(
    Bucket='examplebucket-1250000000',
    Key='exampleobject'
)
print(response)

Sample request with all parameters

response = client.head_object(
    Bucket='examplebucket-1250000000',
    Key='exampleobject',
    VersionId='string',
    IfModifiedSince='Wed, 28 Oct 2020 20:30:00 GMT',
)

Description

Parameter name
ParameterDescription
Local Disk Types
Required
Bucket
Bucket name in the format of BucketName-APPID
String
Required
Key
ObjectKey is the unique identifier of the object in the bucket. For example, in the object's access domain name examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg, the ObjectKey is doc/pic.jpg
String
Required
VersionId
Version ID of the object if versioning is enabled
String
Not required
IfModifiedSince
Returns the object metadata only if the object is modified after the time specified in GMT format
String
Not required

Response description

The response contains object metadata in dict format:
{
    'ETag': '"9a4802d5c99dafe1c04da0a8e7e166bf"',
    'Last-Modified': 'Wed, 28 Oct 2014 20:30:00 GMT',
    'Cache-Control': 'max-age=1000000',
    'Content-Type': 'application/octet-stream',
    'Content-Disposition': 'attachment; filename="filename.jpg"',
    'Content-Encoding': 'gzip',
    'Content-Language': 'zh-cn',
    'Content-Length': '16807',
    'Expires': 'Wed, 28 Oct 2019 20:30:00 GMT',
    'Connection': 'keep-alive',
    'Accept-Ranges': 'bytes',
    'Server': 'tencent-cos',
    'Date': 'Wed, 28 Oct 2019 20:20:00 GMT',
    'x-cos-meta-test': 'test',
    'x-cos-version-id': 'MTg0NDUxODMzMTMwMDM2Njc1ODA',
    'x-cos-hash-crc64ecma': '1220413902487941276',
    'x-cos-request-id': 'NTg3NzQ3ZmVfYmRjMzVfMzE5N182NzczMQ=='
}
Parameter name
ParameterDescription
Local Disk Types
ETag
For multipart uploads, this value does not represent the MD5 checksum of the object content, but is used only to verify the uniqueness of the object.
String
Last-Modified
Time the object was last modified
String
Cache-Control
Cache policy. Standard HTTP header
String
Content-Type
Content type. Standard HTTP header
String
Content-Disposition
File name. Standard HTTP header
String
Content-Encoding
Encoding format. Standard HTTP header
String
Content-Language
Language type. HTTP standard header
String
Content-Length
Object size
String
Expires
Cache expiration time. HTTP standard header
String
Connection
Connection method. Standard HTTP header
String
Accept-Ranges
Range request flag. Standard HTTP header
String
Server
Server flag. Standard HTTP header
String
Date
Request date. Standard HTTP header
String
x-cos-meta-*
User-defined object metadata. It must start with x-cos-meta; otherwise, it will be ignored
String
x-cos-hash-crc64ecma
CRC64 checksum of the file
String
x-cos-version-id
Version ID of the object if versioning is enabled
String
x-cos-request-id
Request ID
String

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