Obtaining a CORS Rule (SDK for Java)

Updated on 2024-12-11 GMT+08:00

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Function

CORS is a browser-standard mechanism defined by the W3C. It allows a web client in one origin to interact with resources in another. For general web page requests, website scripts and contents in one origin cannot interact with those in another due to SOPs. OBS supports CORS, allowing the resources in OBS to be requested across origins.

This API returns the CORS configuration of a bucket.

NOTICE:

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

Restrictions

To obtain the CORS configuration of a bucket, you must be the bucket owner or have the required permission (obs:bucket:GetBucketCORS in IAM or GetBucketCORS 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.getBucketCors(final BaseBucketRequest request)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
request	BaseBucketRequest	Yes	Explanation: Request parameters for obtaining a CORS rule. For details, see Table 2.

**Table 2** BaseBucketRequest
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 3** BucketCors
Parameter	Type	Mandatory (Yes/No)	Description
rules	List<BucketCorsRule>	Yes	Explanation: List of CORS rules of a bucket. For details, see Table 4.

**Table 4** BucketCorsRule
Parameter	Type	Mandatory (Yes/No)	Description
id	String	No	Explanation: CORS rule ID. Value range: The value must contain 1 to 255 characters. Default value: None
allowedMethod	List<String>	Yes	Explanation: The allowed HTTP methods for a cross-origin request, indicating the operation types for buckets and objects. Value range: The following HTTP methods are supported: GET PUT HEAD POST DELETE Default value: None
allowedOrigin	List<String>	Yes	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<String>	No	Explanation: The allowed cross-origin request headers. Only CORS requests matching the allowed headers are valid. Restrictions: Each header can contain only one wildcard character (). Spaces, ampersands (&), colons (:), and less-than signs (<) are not allowed. Default value*: None
maxAgeSeconds	int	No	Explanation: Duration your client can cache the response for a cross-origin request. Restrictions: Each bucket CORS rule can contain only one maxAgeSeconds. Value range: An integer greater than or equal to 0, in seconds. Default value: 100
exposeHeader	List<String>	No	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 the list of the allowed additional headers. Restrictions: Spaces, wildcard characters (), ampersands (&), colons (:), and less-than signs (<) are not allowed. Default value*: None

Code Examples

This example returns the CORS configuration of bucket examplebucket.

    
     
       
       import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.model.BucketCors;
import com.obs.services.model.BucketCorsRule;
public class GetBucketCors001 {
    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 {
            // Obtain the CORS rules.
            BucketCors cors = obsClient.getBucketCors("examplebucket");
            for(BucketCorsRule rule : cors.getRules()){
                System.out.println("Id:" + rule.getId());
                System.out.println("MaxAgeSecond:" + rule.getMaxAgeSecond());
                System.out.println("AllowedHeader:" + rule.getAllowedHeader());
                System.out.println("AllowedOrigin:" + rule.getAllowedOrigin());
                System.out.println("AllowedMethod:" + rule.getAllowedMethod());
                System.out.println("ExposeHeader:" + rule.getExposeHeader());
            }
            System.out.println("getBucketCors successfully");
        } catch (ObsException e) {
            System.out.println("getBucketCors 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("getBucketCors failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}

      

    
   