Configuring a CORS Rule (SDK for Java)
Function
Cross-origin resource sharing (CORS) is a browser-standard mechanism defined by the World Wide Web Consortium (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 Same Origin Policies (SOPs). OBS supports CORS, allowing the resources in OBS to be requested across origins.
You can call ObsClient.setBucketCors to set CORS rules for a bucket. The configured CORS rules follow the principle of new ones overwriting old ones.
If you have any questions during development, post them on the Issues page of GitHub.
Restrictions
- To configure CORS for a bucket, you must be the bucket owner or have the required permission (obs:bucket:PutBucketCORS in IAM or PutBucketCORS 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.setBucketCors(final SetBucketCorsRequest request)
Request Parameters
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
request |
Yes |
Request parameters for setting a CORS rule. For details, see Table 2. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
bucketName |
String |
Yes |
Explanation: Bucket name. Restrictions:
Default value: None |
bucketCors |
Yes |
Explanation: List of CORS rules of a bucket. For details, see Table 3. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
rules |
List<BucketCorsRule> |
Yes |
Explanation: List of CORS rules of a bucket. For details, see Table 4. |
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:
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 |
Responses
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 |
Code Examples
This example configures CORS rules for bucket examplebucket.
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import com.obs.services.ObsClient; import com.obs.services.exception.ObsException; import com.obs.services.model.BucketCors; import com.obs.services.model.BucketCorsRule; import com.obs.services.model.DeleteObjectsRequest; import com.obs.services.model.DeleteObjectsResult; import com.obs.services.model.KeyAndVersion; import java.util.ArrayList; import java.util.List; public class SetBucketCors001 { 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 { //Configure CORS rules. BucketCors cors = new BucketCors(); List<BucketCorsRule> rules = new ArrayList<BucketCorsRule>(); BucketCorsRule rule = new BucketCorsRule(); ArrayList<String> allowedOrigin = new ArrayList<String>(); // Specify the origin of the cross-origin request. allowedOrigin.add( "http://www.a.com"); allowedOrigin.add( "http://www.b.com"); rule.setAllowedOrigin(allowedOrigin); ArrayList<String> allowedMethod = new ArrayList<String>(); // Specify the request method, which can be GET, PUT, DELETE, POST, or HEAD. allowedMethod.add("GET"); allowedMethod.add("HEAD"); allowedMethod.add("PUT"); rule.setAllowedMethod(allowedMethod); ArrayList<String> allowedHeader = new ArrayList<String>(); // Specify whether headers specified in Access-Control-Request-Headers in the OPTIONS request can be used. allowedHeader.add("x-obs-header"); rule.setAllowedHeader(allowedHeader); ArrayList<String> exposeHeader = new ArrayList<String>(); // Specify response headers that users can access using application programs. exposeHeader.add("x-obs-expose-header"); rule.setExposeHeader(exposeHeader); // Specify the browser's cache time of the returned results of OPTIONS requests for specific resources, in seconds. rule.setMaxAgeSecond(10); rules.add(rule); cors.setRules(rules); obsClient.setBucketCors("examplebucket", cors); System.out.println("setBucketCors successfully"); } catch (ObsException e) { System.out.println("setBucketCors 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("setBucketCors failed"); // Print other error information. e.printStackTrace(); } } } |
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