tencent cloud


Querying Object Metadata

Last updated: 2022-05-11 12:10:08


    This document provides an overview of APIs and SDK code samples for querying object metadata.

    API Operation Description
    HEAD Object Querying object metadata Queries the metadata of an object.

    Querying Object Metadata


    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 logging
    # In most cases, set the log level to INFO. If you need to debug, you can set it to DEBUG and the SDK will print the communication information of the client.
    logging.basicConfig(level=logging.INFO, stream=sys.stdout)
    # 1. Set user attributes such as secret_id, secret_key, and region. Appid has been removed from CosConfig and thus needs to be specified in Bucket, which is formatted as BucketName-Appid.
    secret_id = 'SecretId'     # Replace it with the actual SecretId, which can be viewed and managed at https://console.tencentcloud.com/cam/capi
    secret_key = 'SecretKey'     # Replace it with the actual SecretKey, which can be viewed and managed at https://console.tencentcloud.com/cam/capi
    region = 'ap-beijing'      # Replace it with the actual region, which can be viewed in the console at https://console.tencentcloud.com/cos5/bucket
                             # For the list of regions supported by COS, see https://www.tencentcloud.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, visit https://www.tencentcloud.com/document/product/436/14048
    scheme = 'https'           # Specify whether to use HTTP or HTTPS protocol to access COS. This field 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(

    Sample request with all parameters

    response = client.head_object(
      IfModifiedSince='Wed, 28 Oct 2020 20:30:00 GMT',

    Parameter description

    Parameter Description Type Required
    Bucket Bucket name in the format of BucketName-APPID String Yes
    Key Object key, which uniquely identifies an object in a bucket. For example, if an object’s access endpoint is examplebucket-1250000000.cos.ap-guangzhou.myqcloud.com/doc/pic.jpg, its key is doc/pic.jpg. String Yes
    VersionId Version ID of the object if versioning is enabled String No
    IfModifiedSince Required modification time. Metadata is returned only if the object has been modified after the specified time. String No

    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',
      'x-cos-meta-test': 'test',
      'x-cos-version-id': 'MTg0NDUxODMzMTMwMDM2Njc1ODA',
      'x-cos-request-id': 'NTg3NzQ3ZmVfYmRjMzVfMzE5N182NzczMQ=='
    Parameter Description Type
    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 when the object was last modified String
    Cache-Control Cache policy. Standard HTTP header String
    Content-Type Content type. Standard HTTP header String
    Content-Disposition Filename. Standard HTTP header String
    Content-Encoding Encoding type. Standard HTTP header String
    Content-Language Language type. Standard HTTP header String
    Content-Length Object size String
    Expires Cache expiration time. Standard HTTP header String
    x-cos-meta-* User-defined object metadata. This parameter must start with x-cos-meta; otherwise, it will be ignored. String
    x-cos-version-id Version ID of the object if versioning is enabled String
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