Help Center/ Object Storage Service/ SDK Reference/ Python/ Bucket-Related APIs (SDK for Python)/ Configuring CORS for a Bucket (SDK for Python)
Updated on 2024-11-26 GMT+08:00
View PDF

Configuring CORS for a Bucket (SDK for Python)

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

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
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
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.

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
 
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/eu/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. EU-Dublin is used here as an example. Replace it with the one in use.
server = "https://obs.eu-west-101.myhuaweicloud.eu" 

# 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