Help Center/ Object Storage Service/ SDK Reference/ Java/ Buckets (SDK for Java)/ Obtaining the Policy of a Bucket (SDK for Java)
Updated on 2024-06-18 GMT+08:00

Obtaining the Policy of a Bucket (SDK for Java)

Function

OBS provides access control over buckets. You can use an access policy to define whether a user can perform certain operations on a specific bucket. OBS access control can be implemented using IAM permissions, bucket policies, and ACLs. For more information, see Introduction to OBS Access Control.

This API returns the policy of a bucket.

If you have any questions during development, post them on the Issues page of GitHub.

Restrictions

  • OBS returns 404 NoSuchBucketPolicy when you call this API in the following scenarios:
    • The specified bucket policy does not exist.
    • The standard policy of the specified bucket is set to Private and no advanced policies are configured.
  • To obtain the policy of a bucket, you must be the bucket owner or have the required permission (obs:bucket:GetBucketPolicy in IAM or GetBucketPolicy 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.getBucketPolicy(String bucketName)

Request Parameters

Table 1 List of request parameters

Parameter

Type

Mandatory (Yes/No)

Description

bucketName

String

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 attributes comply with those set in the first creation request.

Default value:

None

Responses

Table 2 List of returned results

Parameter

Type

Description

policy

String

Explanation:

Policy information in JSON format

Restrictions:

  • The bucket name contained in the Resource parameter of the policy must be the same as the one specified for the current bucket policy.
  • For details about the policy format, see Bucket Policy Parameters.

Default value:

None

Code Examples

This example returns the policy of bucket exampleBucket.

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import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
public class GetBucketPolicy001 {
    public static void main(String[] args) {
        // Obtain an AK/SK pair using environment variables or import the AK/SK pair in other ways. Using hard coding may result in leakage.
        // Obtain an AK/SK pair on the management console.
        String ak = System.getenv("ACCESS_KEY_ID");
        String sk = System.getenv("SECRET_ACCESS_KEY_ID");
        // (Optional) If you are using a temporary AK/SK pair and a security token to access OBS, you are advised not to use hard coding, which may result in information leakage.
        // Obtain an AK/SK pair and a security token using environment variables or import them in other ways.
        // String securityToken = System.getenv("SECURITY_TOKEN");
        // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one in your actual situation.
        String endPoint = "https://obs.ap-southeast-1.myhuaweicloud.com";
        // Obtain an endpoint using environment variables or import it in other ways.
        //String endPoint = System.getenv("ENDPOINT");
     
        // Create an ObsClient instance.
        // Use the permanent AK/SK pair to initialize the client.
        ObsClient obsClient = new ObsClient(ak, sk,endPoint);
        // Use the temporary AK/SK pair and security token to initialize the client.
        // ObsClient obsClient = new ObsClient(ak, sk, securityToken, endPoint);

        try {
            // Example bucket name
            String exampleBucket = "examplebucket";
            String policy = obsClient.getBucketPolicy(exampleBucket);
            System.out.println("\t" + policy);
        } catch (ObsException e) {
            System.out.println("GetBucketAcl failed");
            // Request failed. Print the HTTP status code.
            System.out.println("HTTP Code:" + e.getResponseCode());
            // Request failed. Print the server-side error code.
            System.out.println("Error Code:" + e.getErrorCode());
            // Request failed. Print the error details.
            System.out.println("Error Message:" + e.getErrorMessage());
            // Request failed. Print the request ID.
            System.out.println("Request ID:" + e.getErrorRequestId());
            System.out.println("Host ID:" + e.getErrorHostId());
            e.printStackTrace();
        } catch (Exception e) {
            System.out.println("GetBucketAcl failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}