Obtaining Bucket Metadata (SDK for Java)

Function

This API returns information about a bucket, including the storage class, region, CORS rules, and redundancy policy.

Restrictions

To obtain bucket metadata, you must be the bucket owner or have the required permission (obs:bucket:HeadBucket in IAM or HeadBucket 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.
For details about values for methods such as BucketMetadataInfoResult.getAllowMethods, see the CORS configurations of the bucket.

Method

obsClient.getBucketMetadata(BucketMetadataInfoRequest request)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
request	BucketMetadataInfoRequest	Yes	Explanation: Request parameters for obtaining bucket metadata. For details, see Table 2.

**Table 2** BucketMetadataInfoRequest
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
origin	String	No	Explanation: Origin of the cross-domain request specified by the preflight request. Generally, it is a domain name. Restrictions: You can configure one or more rules and use at most one wildcard character () in each rule. If you want to configure multiple rules, separate them using a line breaker. Default value*: None
requestHeaders	List<String>	No	Explanation: HTTP headers in a cross-origin request. Only CORS requests matching the allowed headers are valid. Restrictions: You can enter multiple allowed headers, with one separated from another using a line break. Each header can contain one wildcard character () at most. Spaces, ampersands (&), colons (:), and less-than signs (<) are not allowed. Default value*: None

Responses

**Table 3** BucketMetadataInfoResult
Parameter	Type	Description
statusCode	int	Explanation: HTTP status code. Value range: A status code is a group of digits that can be 2xx (indicating successes) or 4xx or 5xx (indicating errors). It indicates the status of a response. For more information, see Status Code. Default value: None
responseHeaders	Map<String, Object>	Explanation: HTTP response header list, composed of tuples. In a tuple, the String key indicates the name of the header, and the Object value indicates the value of the header. Default value: None
location	String	Explanation: Region where a bucket is located. Restrictions: If the used endpoint is obs.myhuaweicloud.com, this parameter is not required. If any other endpoint is used, this parameter is required. Value range: To learn about valid regions and endpoints, see Regions and Endpoints. An endpoint is the request address for calling an API. Endpoints vary depending on services and regions. To obtain the regions and endpoints, contact the enterprise administrator. Default value: If obs.myhuaweicloud.com is used as the endpoint and no region is specified, cn-north-1 (the CN North-Beijing1 region) is used by default.
obsVersion	String	Explanation: OBS version of the bucket. Value range: 3.0 indicates the latest OBS version. -- indicates any version earlier than 3.0. Default value: None
storageClass	StorageClassEnum	Explanation: Bucket storage class that can be specified at bucket creation. Value range: See Table 6. Default value: STANDARD
allowOrigin	String	Explanation: If Origin in the request meets the CORS rules of the bucket, AllowedOrigin specified in the CORS rules is returned. Restrictions: You can configure one or more rules and use at most one wildcard character () in each rule. If you want to configure multiple rules, separate them using a line breaker. Default value*: None
allowHeaders	List<String>	Explanation: If RequestHeader in the request meets the CORS rules of the bucket, AllowedHeader specified in the CORS rules is returned. Restrictions: You can enter multiple allowed headers, with one separated from another using a line break. Each header can contain one wildcard character () at most. Spaces, ampersands (&), colons (:), and less-than signs (<) are not allowed. Default value*: None
allowMethods	List<String>	Explanation: The allowed HTTP methods for a cross-origin request, indicating the operation types of buckets and objects. Value range: The following HTTP methods are supported: GET PUT HEAD POST DELETE Default value: None
exposeHeaders	List<String>	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
maxAge	int	Explanation: Time your client can cache the response for a cross-origin request Restrictions: Each CORS rule can contain only one maxAge. Value range: An integer greater than 0, in seconds Default value: 100
epid	String	Explanation: Enterprise project ID that can be specified at bucket creation. If you have enabled EPS, you can obtain the project ID from the EPS console. Restrictions: The value of Epid is a UUID. If the default enterprise project is used, 0 is passed here or Epid is not included. Epid is not required for those who have not enabled the EPS. Example: 9892d768-2d13-450f-aac7-ed0e44c2585f Value range: See How Do I Obtain an Enterprise Project ID? Default value: None
bucketType	BucketTypeEnum	Explanation: Type of the bucket Value range: See Table 4. Default value: OBJECT, indicating an object bucket
availableZone	AvailableZoneEnum	Explanation: Data redundancy policy of the bucket, indicating whether data is stored in a single AZ or multiple AZs. For details, see Table 5. Restrictions: Value 3az means that data is stored in multiple AZs in the same region. If this header is not contained, data is stored in a single AZ. Default value: None

**Table 4** BucketTypeEnum
Constant	Default Value	Description
OBJECT	OBJECT	Object buckets.
PFS	POSIX	Parallel file systems.

**Table 5** AvailableZoneEnum
Constant	Default Value	Description
MULTI_AZ	3az	Multi-AZ redundancy

**Table 6** StorageClassEnum
Constant	Default Value	Description
STANDARD	STANDARD	Standard storage class.
WARM	WARM	Infrequent Access storage class.
COLD	COLD	Archive storage class.

Code Examples

This example obtains the metadata of bucket examplebucket. The origin of the cross-origin request is http://www.exampleorigin.com.

    
     
       
       
         import com.obs.services.ObsClient;
import com.obs.services.exception.ObsException;
import com.obs.services.model.BucketMetadataInfoRequest;
import com.obs.services.model.BucketMetadataInfoResult;
public class GetBucketMetadata001 {
    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";
            //Example origin
            String exampleOrigin = "http://www.exampleorigin.com";
            BucketMetadataInfoRequest request = new BucketMetadataInfoRequest(exampleBucket);
            // Specify setOrigin only when cross origin resource sharing (CORS) is used.
            request.setOrigin(exampleOrigin);
            // Obtain the bucket metadata.
            BucketMetadataInfoResult result = obsClient.getBucketMetadata(request);
            System.out.println("GetBucketMetadata successfully");
            System.out.println("GetBucketType:" + result.getBucketType());
            System.out.println("GetLocation:" + result.getLocation());
            System.out.println("GetBucketStorageClass:" + result.getBucketStorageClass());
            System.out.println("GetObsVersion:" + result.getObsVersion());
            System.out.println("GetAllowOrigin:" + result.getAllowOrigin());
            System.out.println("GetMaxAge:" + result.getMaxAge());
            System.out.println("GetAllowHeaders:" + result.getAllowHeaders());
            System.out.println("GetAllowMethods:" + result.getAllowMethods());
            System.out.println("GetExposeHeaders:" + result.getExposeHeaders());
        } catch (ObsException e) {
            System.out.println("GetBucketMetadata 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("GetBucketMetadata failed");
            // Print other error information.
            e.printStackTrace();
        }
    }
}

        

      

    
   