Creating a Signed URL (SDK for Python)

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

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Function

This API creates a URL whose Query parameters are carried with authentication information by specifying the AK and SK, HTTP method, and request parameters. You can provide other users with this URL for temporary access. When generating a URL, you need to specify the validity period of the URL to restrict the access duration of visitors.

If you want to grant other users the permission to perform other operations on buckets or objects (for example, upload or download objects), generate a URL with the corresponding request (for example, to upload an object using the URL that generates the PUT request) and provide the URL for other users.

Restrictions

The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.

If a CORS or signature mismatch error occurs, refer to the following steps to troubleshoot the issue:
1. If CORS is not configured, you need to configure CORS rules on OBS Console. For details, see Configuring CORS.
2. If the signatures do not match, check whether signature parameters are correct. For details, see Authentication of Signature in a URL. For example, during an object upload, the backend uses Content-Type to calculate the signature and generate an authorized URL, but if Content-Type is not set or is set to an incorrect value when the frontend uses the authorized URL, a CORS error occurs. To avoid this issue, ensure that Content-Type fields at both the frontend and backend are kept consistent.

Method

ObsClient.createSignedUrl(method, bucketName, objectKey, specialParam, expires, headers, queryParams)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
method	str	Yes	Explanation: HTTP methods Value range: GET POST PUT DELETE HEAD Default value: None
bucketName	str	No	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 attributes comply with those set in the first creation request. Default value: None
objectKey	str	No	Explanation: Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path that does not contain the bucket name. For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt. Value range: The value must contain 1 to 1,024 characters. Default value: None
specialParam	str	No	Explanation: Special operator, which indicates the sub-resource to be operated Value range: versions uploads location storageinfo quota storagePolicy acl append logging policy lifecycle website versioning cors notification tagging delete restore Default value: None
expires	int	No	Explanation: Expiration time of the signed URL Value range: The value of this parameter for temporary credentials ranges from 0 to 86400, in seconds. The value of this parameter for permanent keys ranges from 0 to 31536000, in seconds. Default value: 300
headers	dict	No	Explanation: Headers in the request Default value: None
queryParams	dict	No	Explanation: Query parameters in the request Default value: None

CAUTION:

If a CORS or signature mismatch error occurs, refer to the following steps to troubleshoot the issue:

If CORS is not configured, you need to configure CORS rules on OBS Console. For details, see Configuring CORS.
If the signatures do not match, check whether signature parameters are correct. For details, see Authentication of Signature in a URL. For example, during an object upload, the backend uses Content-Type to calculate the signature and generate an authorized URL, but if Content-Type is not set or is set to an incorrect value when the frontend uses the authorized URL, a CORS error occurs. To avoid this issue, ensure that Content-Type fields at both the frontend and backend are kept consistent.

Responses

**Table 2** List of returned results
Parameter	Type	Description
signedUrl	str	Explanation: Signed URL Default value: None
actualSignedRequestHeaders	dict	Explanation: Actual headers in the request initiated by using the signed URL Default value: None

Code Examples

This example creates temporary signed URLs.

    
     
       
       from obs import ObsClient
import os
import traceback
import base64

# 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:
    # Create a signed URL for creating a bucket.
    res1 = obsClient.createSignedUrl(method='PUT', bucketName='bucketname', expires=3600)
    print('signedUrl:', res1.signedUrl)
    print('actualSignedRequestHeaders:', res1.actualSignedRequestHeaders)

    # Create a signed URL for uploading an object.
    res2 = obsClient.createSignedUrl(method='PUT', bucketName='bucketname', objectKey='objectkey', expires=3600,
                                     headers={'Content-Type': 'text/plain'})
    print('signedUrl:', res2.signedUrl)
    print('actualSignedRequestHeaders:', res2.actualSignedRequestHeaders)

    # Create a signed URL for setting an object ACL.
    res3 = obsClient.createSignedUrl(method='PUT', bucketName='bucketname', objectKey='objectkey', specialParam='acl',
                                     expires=3600, headers={'x-obs-acl': 'private'})
    print('signedUrl:', res3.signedUrl)
    print('actualSignedRequestHeaders:', res3.actualSignedRequestHeaders)

    # Create a signed URL for downloading an object.
    res4 = obsClient.createSignedUrl(method='GET', bucketName='bucketname', objectKey='objectkey', expires=3600)
    print('signedUrl:', res4.signedUrl)
    print('actualSignedRequestHeaders:', res4.actualSignedRequestHeaders)

    # Create a signed URL for deleting an object.
    res5 = obsClient.createSignedUrl(method='DELETE', bucketName='bucketname', objectKey='objectkey', expires=3600)
    print('signedUrl:', res5.signedUrl)
    print('actualSignedRequestHeaders:', res5.actualSignedRequestHeaders)

    # Create a signed URL for deleting a bucket.
    res6 = obsClient.createSignedUrl(method='DELETE', bucketName='bucketname', expires=3600)
    print('signedUrl:', res6.signedUrl)
    print('actualSignedRequestHeaders:', res6.actualSignedRequestHeaders)

    # Create a signed URL for initiating a multipart task.
    res7 = obsClient.createSignedUrl(method='POST', bucketName='bucketname', objectKey='objectkey',
                                     specialParam='uploads', expires=3600)
    print('signedUrl:', res7.signedUrl)
    print('actualSignedRequestHeaders:', res7.actualSignedRequestHeaders)

    # Create a signed URL for uploading a part.
    res8 = obsClient.createSignedUrl(method='PUT', bucketName='bucketname', objectKey='objectkey', expires=3600,
                                     queryParams={'partNumber': '1', 'uploadId': '00000*****'})
    print('signedUrl:', res8.signedUrl)
    print('actualSignedRequestHeaders:', res8.actualSignedRequestHeaders)

    # Create a signed URL for assembling parts.
    res9 = obsClient.createSignedUrl(method='POST', bucketName='bucketname', objectKey='objectkey', expires=3600,
                                     queryParams={'uploadId': '00000*****'})
    print('signedUrl:', res9.signedUrl)
    print('actualSignedRequestHeaders:', res9.actualSignedRequestHeaders)

    # Create a signed URL for image persistency.
    # Name of the bucket that stores the source object
    bucketName = 'originBucketName'; 
    # Source object name before the processing
    objectKey = 'test.png';

    # Name of the object after processing
    targetObjectName ="save.png"
    # (Optional) Name of the bucket that stores the new object
    targetBucketName ="saveBucketName"
    queryParams={}
    queryParams["x-image-process"]="image/resize,w_100"
    queryParams["x-image-save-object"]=base64.b64encode(targetObjectName .encode("utf-8")).decode()
    # Optional parameter
    queryParams["x-image-save-bucket"]=base64.b64encode(targetBucketName .encode("utf-8")).decode()

    res10 = obsClient.createSignedUrl(method='GET', bucketName=bucketName, objectKey=objectKey, queryParams=queryParams, expires=3600)
    print('signedUrl:', res10.signedUrl)
    print('actualSignedRequestHeaders:', res10.actualSignedRequestHeaders)
except:
    print(traceback.format_exc())

      

    
   

Parent topic: Other APIs (SDK for Python)

Previous topic: Other APIs (SDK for Python)

Next topic: Generating Authentication Parameters for Browser-Based Uploads (SDK for Python)

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