Updated on 2026-08-14 GMT+08:00

Uploading an Object - Browser-Based (SDK for Go)

Function

This API upload an object smaller than 5 GB to a specified bucket in HTML form. You can perform the following steps to perform a browser-based upload:

Call ObsClient.CreateBrowserBasedSignature to generate request parameters for authentication.
Prepare an HTML form page.
Enter the request parameters in the HTML page.
Select a local file and upload it in browser-based mode.

There are two request parameters generated:

policy: corresponding to the policy parameter in the form. For details, see Authentication of Signature Carried in the Table Uploaded Through a Browser.
signature: corresponding to the signature parameter in the form

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 result of ObsClient.createPostSignature.

Method

func (obsClient ObsClient) CreateBrowserBasedSignature(input *CreateBrowserBasedSignatureInput) (output *CreateBrowserBasedSignatureOutput, err error)

Request Parameters

**Table 1** List of request parameters
Parameter	Type	Mandatory (Yes/No)	Description
input	*CreateBrowserBasedSignatureInput	Yes	Explanation: Input parameters for a browser-based upload. For details, see Table 2.

**Table 2** CreateBrowserBasedSignatureInput
Parameter	Type	Mandatory (Yes/No)	Description
Bucket	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 a period (.) and a hyphen (-) 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
Key	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
Expires	int	No	Explanation: Expiration time of authentication for a browser-based upload Value range: A positive integer, in seconds Default value: 300
FormParams	map[string]string	No	Explanation: Parameters of a browser-based upload, not including key, policy, and signature Value range: acl, cache-control, content-type, content-disposition, content-encoding, and expires Default value: None

Responses

**Table 3** List of returned results
Parameter	Type	Description
output	*CreateBrowserBasedSignatureOutput	Explanation: Returned results. For details, see Table 4.
err	error	Explanation: Error messages returned by the API

**Table 4** CreateBrowserBasedSignatureOutput
Parameter	Type	Description
OriginPolicy	string	Explanation: policy not encoded by Base64. This parameter can only be used for verification. 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 policy in the form Example: eyJleHBpcmF0aW9uIjoiMjAyMy0wOS0xMlQxMjo1Mjo1OVoiLCJjb25kaXRpb25zIjpbeyJjb250ZW50LXR5cGUiOiJ0ZXh0L3BsYWluIn0seyJidWNrZXQiOiJleGFtcGxlYnVja2V0In0seyJrZXkiOiJleGFtcGxlL29iamVjdG5hbWUifSxdfQ== Default value: None
Signature	string	Explanation: signature in the form Example: g0jQr4v9VWd1Q2FOFDG6LGfV9Cw= Default value: None

Code Examples

     // Import a dependency.
import (
       "fmt"
       "obs"
)


func main() {
    //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. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    ak := os.Getenv("AccessKeyID")
    sk := os.Getenv("SecretAccessKey")
    // (Optional) If you use a temporary AK/SK pair and a security token to access OBS, you are not advised to use hard coding, which may result in information leakage. You can obtain an AK/SK pair using environment variables or import an AK/SK pair in other ways.
    // securityToken := os.Getenv("SecurityToken")
    // Enter the endpoint corresponding to the bucket. CN-Hong Kong is used here as an example. Replace it with the one currently in use.
    endPoint := "https://obs.ap-southeast-1.myhuaweicloud.com"
    // Create an obsClient instance.
    // If you use a temporary AK/SK pair and a security token to access OBS, use the obs.WithSecurityToken method to specify a security token when creating an instance.
    obsClient, _:= obs.New(ak, sk, endPoint/*, obs.WithSecurityToken(securityToken)*/)

    input := &obs.CreateBrowserBasedSignatureInput{}
    // Set form parameters.
    formParams := make(map[string]string)
    // Set the object ACL to public read.
    formParams["x-obs-acl"] = string(obs.AclPublicRead)
    // Specify the MIME type for the object.
    formParams["content-type"] = "text/plain"
    input.FormParams = formParams
    // Set the validity period of the browser-based upload request, in seconds.
    input.Expires = 3600
    output, _ := obsClient.CreateBrowserBasedSignature(input)
    // Obtain the request parameters.
    fmt.Printf("Policy:%s\n", output.Policy)
    fmt.Printf("Signature:%s\n", output.Signature)
}
 
 
  

Sample code of an HTML form is as follows:

     <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">
            <p>
                Object key
            </p>            
            <!-- Object name -->
            <input type="text" name="key" value="objectname" />
            <p>
                ACL
            </p>
            <!-- Object ACL permission -->
            <input type="text" name="x-obs-acl" value="public-read" />
            <p>
                Content-Type
            </p>
            <!-- MIME type of the object -->
            <input type="text" name="content-type" value="text/plain" />
            <p>            
                <!-- Base64-encoded policy -->
                <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 ***"/>
                <input name="file" type="file" />
                <input name="submit" value="Upload" type="submit" />
            </p>
        </form>
    </body>
</html>
 
 
  

Helpful Links

Parent topic: Object Upload Overview (SDK for Go)