Help Center> Object Storage Service> Java> Object Upload (SDK for Java)> Uploading an Object - Browser-Based (SDK for Java)
Updated on 2024-04-19 GMT+08:00

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:

  1. Call ObsClient.createPostSignature to generate request parameters for authentication.
  2. Prepare an HTML form.
  3. Enter the request parameters in the page.
  4. 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

  • 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)

Table 1 createPostSignature

Parameter

Type

Mandatory (Yes/No)

Description

request

PostSignatureRequest

Yes

Explanation:

Request parameters for a browser-based upload. For details, see Table 2.

Table 2 PostSignatureRequest

Parameter

Type

Mandatory (Yes/No)

Description

bucketName

String

No

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

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

Table 3 PostSignatureResponse

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>