Updated on 2026-09-22 GMT+08:00

Performing a Form-based Upload

If you have any questions during development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see API Reference.

Performing a form-based upload is to upload objects to a specified bucket in HTML form. The maximum size of an object is 5 GB.

You can call ObsClient->createPostSignature to generate request parameters for form-based upload. You can also perform a form-based according to the following procedure:

  1. Call ObsClient->createPostSignature to generate request parameters for authentication.
  2. Prepare an HTML form page.
  3. Enter the request parameters in the HTML page.
  4. Select a local file and upload it in form-based mode.

There are two request parameters generated:

  • Policy, which corresponds to the policy field in the form
  • Signature: which corresponds to the signature field in the form

The following sample code shows how to generate the parameters in a form-based upload request.

<?php
// Import the dependency library.
require 'vendor/autoload.php';
// Import the SDK code library during the installation with the source code.
// require 'obs-autoloader.php';
// Declare the namespace.
use Obs\ObsClient;
use Obs\ObsException;

// Create an ObsClient instance.
$obsClient = new ObsClient([
    // Obtain an AK/SK pair using environment variables (recommended) or import an AK/SK pair in other ways. Using hard coding may result in leakage.
    // Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    'key' => getenv('ACCESS_KEY_ID'),
    'secret' => getenv('SECRET_ACCESS_KEY'),
    'endpoint' => 'https://your-endpoint',
    'signature' => 'obs'
]);

// Generate a signature for form-based upload.
try {
    $resp = $obsClient->createPostSignature([
        // Set the validity period of the form-based upload request, in seconds.
        'Expires' => 3600,
        // Set form parameters.
        'FormParams' => [
            // Set the object ACL to public read.
            'x-obs-acl' => ObsClient::AclPublicRead,
            // Set the object MIME type.
            'content-type' => 'text/plain',
        ]
    ]);

    // Obtain the request parameters for the form-based upload.
    printf("Policy:%s\n", $resp['Policy']);
    printf("Signature:%s\n", $resp['Signature']);
} catch (ObsException $e) {
    // If the operation fails, obtain the exception details.
    printf("CreatePostSignatureFailed: Status:%d, Code:%s, Message:%s\n",
        $e->getStatusCode(), $e->getExceptionCode(), $e->getExceptionMessage());
} finally {
    // Close ObsClient to release resources.
    $obsClient->close();
}

Code of an HTML form example is as follows:

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
</head>
<body>

<form action="https://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>
<!-- Base64 code of the policy -->
<input type="hidden" name="policy" value="*** Provide your policy ***" />
<!-- AK -->
<input type="hidden" name="AccessKeyId" value="*** Provide your access key ***"/>
<!-- Signature information -->
<input type="hidden" name="signature" value="*** Provide your signature ***"/>

<input name="file" type="file" />
<input name="submit" value="Upload" type="submit" />
</form>
</body>
</html>
  • Values of policy and signature in the HTML form are obtained from the returned results of ObsClient->createPostSignature.
  • You can directly download the HTML form example: PostDemo.