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Help Center/ Object Storage Service/ SDK Reference/ Python/ Bucket-Related APIs (SDK for Python)/ Configuring CORS for a Bucket (SDK for Python)

Configuring CORS for a Bucket (SDK for Python)

Updated on 2025-02-26 GMT+08:00

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Function

Cross-origin resource sharing (CORS) is a mechanism defined by the World Wide Web Consortium (W3C) that allows a web application program in one domain to access resources located in another one. For general web page requests, website scripts and contents in one domain cannot interact with those in another because of Same Origin Policies (SOPs). OBS supports CORS rules that allow the resources in OBS to be requested by other domains.

This API configures CORS for a bucket.

Restrictions

To configure CORS for a bucket, you must be the bucket owner or have the required permission (obs:bucket:PutBucketCORS in IAM or PutBucketCORS in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Creating a Custom Bucket Policy.
The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.

Method

ObsClient.setBucketCors(bucketName, corsRuleList, extensionHeaders)

Request Parameters

Parameter	Type	Mandatory (Yes/No)	Description
bucketName	str	Yes	Explanation: Bucket name Restrictions: A bucket name must be unique across all accounts and regions. A bucket name: Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed. Cannot be formatted as an IP address. Cannot start or end with a hyphen (-) or period (.). Cannot contain two consecutive periods (..), for example, my..bucket. Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket. If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket properties comply with those set in the first creation request. Default value: None
corsRuleList	list of CorsRule	Yes	Explanation: CORS rule list of the bucket. For details, see Table 1. Restrictions: A list can have a maximum of 100 CORS rules. Default value: None
extensionHeaders	dict	No	Explanation: Extension headers. Value range: See User-defined Header (SDK for Python). Default value: None

Parameter

Type

Mandatory (Yes/No)

Description

bucketName

str

Yes

Explanation:

Bucket name

Restrictions:

A bucket name must be unique across all accounts and regions.
A bucket name:
- Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed.
- Cannot be formatted as an IP address.
- Cannot start or end with a hyphen (-) or period (.).
- Cannot contain two consecutive periods (..), for example, my..bucket.
- Cannot contain periods (.) and hyphens (-) adjacent to each other, for example, my-.bucket or my.-bucket.
If you repeatedly create buckets of the same name in the same region, no error will be reported and the bucket properties comply with those set in the first creation request.

Default value:

None

corsRuleList

list of CorsRule

Yes

Explanation:

CORS rule list of the bucket. For details, see Table 1.

Restrictions:

A list can have a maximum of 100 CORS rules.

Default value:

None

extensionHeaders

dict

Explanation:

Extension headers.

Value range:

See User-defined Header (SDK for Python).

Default value:

None

**Table 1** CorsRule
Parameter	Type	Mandatory (Yes/No)	Description
id	str	No if used as a request parameter	Explanation: CORS rule ID Value range: The value must contain 1 to 255 characters. Default value: None
allowedMethod	list of str	Yes if used as a request parameter	Explanation: The allowed HTTP methods (types of operations on buckets and objects) for a cross-origin request. Value range: The following HTTP methods are supported: GET PUT HEAD POST DELETE Default value: None
allowedOrigin	list of str	Yes if used as a request parameter	Explanation: The origin from which the requests can access the bucket. Restrictions: Domain name of the origin. Each origin can contain only one wildcard character (), for example, https://.vbs.example.com. Default value**: None
allowedHeader	list of str	No if used as a request parameter	Explanation: The allowed headers for cross-origin requests. Only CORS requests matching the allowed headers are valid. Restrictions: Each header can contain at most one wildcard character (). Spaces, ampersands (&), colons (:), less-than signs (<), and full-width characters are not allowed. Default value*: None
maxAgeSecond	int or str	No if used as a request parameter	Explanation: Time your client can cache the response for a cross-origin request Restrictions: Each CORS rule can contain at most one maxAgeSecond. Value range: An integer greater than or equal to 0, in seconds Default value: 100
exposeHeader	list of str	No if used as a request parameter	Explanation: The CORS-allowed additional headers in the response. These headers provide additional information to clients. By default, your browser can only access headers Content-Length and Content-Type. If your browser needs to access other headers, add them to a list of the allowed additional headers. Restrictions: Spaces, wildcard characters (), ampersands (&), colons (:), and less-than signs (<) are not allowed. Default value*: None

Responses

Type	Description
GetResult	Explanation: SDK common results

Type

Description

GetResult

Explanation:

SDK common results

**Table 2** GetResult
Parameter	Type	Description
status	int	Explanation: HTTP status code Value range: A status code is a group of digits ranging from 2xx (indicating successes) to 4xx or 5xx (indicating errors). It indicates the status of a response. For more information, see Status Code. Default value: None
reason	str	Explanation: Reason description. Default value: None
errorCode	str	Explanation: Error code returned by the OBS server. If the value of status is less than 300, this parameter is left blank. Default value: None
errorMessage	str	Explanation: Error message returned by the OBS server. If the value of status is less than 300, this parameter is left blank. Default value: None
requestId	str	Explanation: Request ID returned by the OBS server Default value: None
indicator	str	Explanation: Error indicator returned by the OBS server. Default value: None
hostId	str	Explanation: Requested server ID. If the value of status is less than 300, this parameter is left blank. Default value: None
resource	str	Explanation: Error source (a bucket or an object). If the value of status is less than 300, this parameter is left blank. Default value: None
header	list	Explanation: Response header list, composed of tuples. Each tuple consists of two elements, respectively corresponding to the key and value of a response header. Default value: None
body	object	Explanation: Result content returned after the operation is successful. If the value of status is larger than 300, the value of body is null. The value varies with the API being called. For details, see Bucket-Related APIs (SDK for Python) and Object-Related APIs (SDK for Python). Default value: None

Code Examples

This example configures CORS rules for bucket examplebucket.

    
     
       
       from obs import ObsClient
from obs import CorsRule
import os
import traceback

# Obtain an AK and SK pair using environment variables or import the AK and SK pair in other ways. Using hard coding may result in leakage.
# Obtain an AK and SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
ak = os.getenv("AccessKeyID")
sk = os.getenv("SecretAccessKey")
# (Optional) If you use a temporary AK and SK pair and a security token to access OBS, obtain them from environment variables.
# security_token = os.getenv("SecurityToken")
# Set server to the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in use.
server = "https://obs.ap-southeast-1.myhuaweicloud.com"

# Create an obsClient instance.
# If you use a temporary AK and SK pair and a security token to access OBS, you must specify security_token when creating an instance.
obsClient = ObsClient(access_key_id=ak, secret_access_key=sk, server=server)
try:
    # Specify CORS rules.
    cors1 = CorsRule(id='rule1', allowedMethod=['PUT', 'POST', 'GET', 'DELETE', 'HEAD'],
                     allowedOrigin=['obs.hostname', 'obs.hostname1'], allowedHeader=['obs-header-1'],
                     maxAgeSecond=60)
    cors2 = CorsRule(id='rule2', allowedMethod=['PUT', 'POST', 'GET'],
                     allowedOrigin=['obs.hostname', 'obs.hostname1'], allowedHeader=['header-1', 'header-2'],
                     maxAgeSecond=50, exposeHeader=['head1'])
    corsList = [cors1, cors2]
    bucketName = "examplebucket"
    # Configure CORS for the bucket.
    resp = obsClient.setBucketCors(bucketName, corsList)

    # If status code 2xx is returned, the API is called successfully. Otherwise, the API call fails.
    if resp.status < 300:
        print('Set Bucket Cors Succeeded')
        print('requestId:', resp.requestId)
    else:
        print('Set Bucket Cors Failed')
        print('requestId:', resp.requestId)
        print('errorCode:', resp.errorCode)
        print('errorMessage:', resp.errorMessage)
except:
    print('Set Bucket Cors Failed')
    print(traceback.format_exc())

      

    
   

Helpful Links

Parent topic: Bucket-Related APIs (SDK for Python)

Previous topic: Obtaining the Versioning Status of a Bucket (SDK for Python)

Next topic: Obtaining the CORS Configuration of a Bucket (SDK for Python)

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