Uploading an Object - Browser-Based (SDK for Java)
Function
This API uploads an object up to 5 GB to a specified bucket in HTML form.
You can call ObsClient.createPostSignature to generate request parameters for a browser-based upload. You can use code to simulate a browser-based upload. For details, see PostObjectSample. You can also perform a browser-based upload with the following steps:
- Call ObsClient.createPostSignature to generate request parameters for authentication.
- Prepare an HTML form.
- Enter the request parameters in the page.
- Select a local file and upload it in browser-based mode.
There are two request parameters generated for authentication:
- Policy, which corresponds to the policy parameter in the form
- Signature, which corresponds to the signature parameter in the form
If you have any questions during development, post them on the Issues page of GitHub.
Restrictions
- To upload an object, you must be the bucket owner or have the required permission (obs:object:PutObject in IAM or PutObject in a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
- The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
- Values of policy and signature in the HTML form are obtained from the returned results of ObsClient.createPostSignature.
- During the object upload, the value of contentType needs to be manually changed to the corresponding Content-Type value.
- When configuring an object ACL, obtain the acl value in the HTML form by referring to Predefined Access Control Policies in OBS.
- You can directly download the HTML form example: PostDemo.
Method
obsClient.createPostSignature(PostSignatureRequest request)
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
request |
Yes |
Explanation: Request parameters for a browser-based upload. For details, see Table 2. |
Parameter |
Type |
Mandatory (Yes/No) |
Description |
---|---|---|---|
bucketName |
String |
No |
Explanation: Bucket name. Restrictions:
Default value: None |
objectKey |
String |
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 |
requestDate |
Date |
No |
Explanation: Time the request is initiated. Default value: None |
expiryDate |
Date |
No |
Explanation: Date of expiry. Default value: None |
expires |
long |
No |
Explanation: Validity period of authentication for a browser-based upload Value range: An integer greater than 0, in seconds. Default value: 300 |
conditions |
List<String> |
No |
Explanation: The conditions specified for the form. The SDK uses the specified value to calculate the policy and ignores the formParams. Default value: None |
formParams |
Map<String, Object> |
No |
Explanation: Form parameters in the request. String indicates the name of the form parameter, and Object indicates the value of the form parameter. Default value: None |
Responses
Parameter |
Type |
Description |
---|---|---|
OriginPolicy |
String |
Explanation: Value of Policy that is not encoded by Base64. This parameter can only be used for verification. For example: {"expiration":"2023-09-12T12:52:59Z","conditions":[{"content-type":"text/plain"},{"bucket":"examplebucket"},{"key":"example/objectname"},]}" Default value: None |
Policy |
String |
Explanation: Base64-encoded value of the policy. For example: eyJleHBpcmF0aW9uIjoiMjAyMy0wOS0xMlQxMjo1Mjo1OVoiLCJjb25kaXRpb25zIjpbeyJjb250ZW50LXR5cGUiOiJ0ZXh0L3BsYWluIn0seyJidWNrZXQiOiJleGFtcGxlYnVja2V0In0seyJrZXkiOiJleGFtcGxlL29iamVjdG5hbWUifSxdfQ== Default value: None |
Signature |
String |
Explanation: signature in the form. For example: g0jQr4v9VWd1Q2FOFDG6LGfV9Cw= Default value: None |
Code Examples
This example generates authorization parameters for a browser-based upload.
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import com.obs.services.ObsClient; import com.obs.services.exception.ObsException; import com.obs.services.model.PostSignatureRequest; import com.obs.services.model.PostSignatureResponse; import java.util.HashMap; import java.util.Map; public class PostObject001 { 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 { // Generate a request for a browser-based upload. PostSignatureRequest request = new PostSignatureRequest(); // Set form parameters. Map<String, Object> formParams = new HashMap<String, Object>(); // Set the object ACL to public-read. formParams.put("x-obs-acl", "public-read"); // Set the MIME type for an object. formParams.put("content-type", "text/plain"); request.setFormParams(formParams); // Set the validity period for the browser-based upload request, in seconds. request.setExpires(3600); PostSignatureResponse response = obsClient.createPostSignature(request); System.out.println("createPostSignature successfully"); // Obtain the request parameters. System.out.println("Policy:" + response.getPolicy()); System.out.println("Signature:" + response.getSignature()); } catch (ObsException e) { System.out.println("createPostSignature 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("createPostSignature failed"); // Print other error information. e.printStackTrace(); } } } |
This example is an HTML form.
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<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> </head> <body> <form action="http://bucketname.your-endpoint/" method="post" enctype="multipart/form-data"> Object key <!-- Object name --> <input type="text" name="key" value="objectname" /> <p> ACL <!-- Object ACL --> <input type="text" name="x-obs-acl" value="public-read" /> <p> Content-Type <!-- Object MIME type --> <input type="text" name="content-type" value="text/plain" /> <p> <!-- Use the value returned by PostSignatureResponse.getPolicy(). --> <input type="hidden" name="policy" value="*** Provide your policy ***" /> <!-- AK --> <input type="hidden" name="AccessKeyId" value="*** Provide your access key ***"/> <!-- Signature string --> <input type="hidden" name="signature" value="*** Provide your signature ***"/> <!-- If x-obs-security-token exists, remove the comment for the following line and specify the actual value of x-obs-security-token. --> <!-- <input type="hidden" name="x-obs-security-token" value="*** Provide your x-obs-security-token ***"/>--> <input name="file" type="file" /> <input name="submit" value="Upload" type="submit" /> </form> </body> </html> |
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