Initialization

Updated at：2025-11-11

Confirm Endpoint

The service domain name of Cloud Smart Network API is: csn.baidubce.com

The API supports both HTTP and HTTPS call methods. For enhanced data security, it is advised to use HTTPS for communication.

Retrieve access key

To utilize Baidu AI Cloud Object Storage (CSN), you need a valid AK (Access Key ID) and SK (Secret Access Key) for signature verification. AK and SK are system-generated strings used to identify users and perform certified authentication with CSN.

Your AK/SK information can be obtained and understood through the following steps:

Create AK/SK

Create a new CSN client

The CSN client acts as the interface for CSN services, offering developers various methods to interact with the CSN services.

Create a new CSN client with AK/SK

Users can refer to the following code to create a new CSN Client to access CSN with AK/SK:

1import (
2	"github.com/baidubce/bce-sdk-go/services/csn"
3)
4func main() {
5 // User’s Access Key ID and Secret Access Key
6	ACCESS_KEY_ID, SECRET_ACCESS_KEY := <your-access-key-id>, <your-secret-access-key>
7	
8 // User-specified Endpoint
9	ENDPOINT := <domain-name>
10 // Initialize a CSNClient
11	csnClient, err := csn.NewClient(AK, SK, ENDPOINT)
12}

In the code above, ACCESS_KEY_ID corresponds to “Access Key ID” in the console. SECRET_ACCESS_KEY corresponds to “Access Key Secret” in the console. Refer to the Guide - How to Retrieve AKSK. The third parameter ENDPOINT takes the value csn.baidubce.com. If set to an empty string, the default domain name will be used as the service address for CSN.

Create a CSN client with STS

Request STS Token

CSN provides temporary third-party access authorization via the STS mechanism. STS (Security Token Service) is a temporary authorization service provided by Baidu AI Cloud. Through STS, you can issue access credentials with customizable validity periods and permissions for third-party users. These users can then use the credentials to call Baidu AI Cloud APIs or SDKs directly to access cloud resources.

To access CSN via STS, users must first request an authentication token from the STS client.

Create CSN Client with STS Token

Once the STS token is obtained, configure it within the CSN Client to enable the creation of an STS-enabled CSN client.

Code example

The GO SDK implements the STS service API. Below is a complete example for requesting an STS Token and creating an CSN Client object:

1import (
2	"fmt"
3 "github.com/baidubce/bce-sdk-go/auth"                    //Import the authentication module
4 "github.com/baidubce/bce-sdk-go/services/csn" //Import CSN service module
5 "github.com/baidubce/bce-sdk-go/services/sts"            //Import the Baige service module
6)
7func main() {
8 //Create a Client object for the STS service, using the default Endpoint
9	AK, SK := <your-access-key-id>, <your-secret-access-key>
10	stsClient, err := sts.NewClient(AK, SK)
11	if err != nil {
12		fmt.Println("create sts client object :", err)
13		return
14	}
15 //Obtain a temporary authentication token with a validity period of 60 seconds and an empty ACL
16	stsObj, err := stsClient.GetSessionToken(60, "")
17	if err != nil {
18		fmt.Println("get session token failed:", err)
19		return
20    }
21	fmt.Println("GetSessionToken result:")
22	fmt.Println("  accessKeyId:", stsObj.AccessKeyId)
23	fmt.Println("  secretAccessKey:", stsObj.SecretAccessKey)
24	fmt.Println("  sessionToken:", stsObj.SessionToken)
25	fmt.Println("  createTime:", stsObj.CreateTime)
26	fmt.Println("  expiration:", stsObj.Expiration)
27	fmt.Println("  userId:", stsObj.UserId)
28 //Create a CSN Client object using the requested temporary STS, with the default endpoint
29	csnClient, err := csn.NewClient(stsObj.AccessKeyId, stsObj.SecretAccessKey, "csn.baidubce.com")
30	if err != nil {
31		fmt.Println("create csn client failed:", err)
32		return
33	}
34	stsCredential, err := auth.NewSessionBceCredentials(
35		stsObj.AccessKeyId,
36		stsObj.SecretAccessKey,
37		stsObj.SessionToken)
38	if err != nil {
39		fmt.Println("create sts credential object failed:", err)
40		return
41	}
42	csnClient.Config.Credentials = stsCredential
43}

Note: Currently, when configuring a CSN Client using STS, the endpoint of STS must be configured as http://sts.bj.baidubce.com.

Configure HTTPS access to CSN

CSN supports the HTTPS transport protocol. To use HTTPS to access CSN services with the CSN Go SDK, specify HTTPS in the endpoint when creating the CSN client object.

1// import "github.com/baidubce/bce-sdk-go/services/csn"
2 NDPOINT := "https://csn.baidubce.com " //Specify the use of HTTPS protocol
3AK, SK := <your-access-key-id>, <your-secret-access-key>
4csnClient, _ := csn.NewClient(AK, SK, ENDPOINT)

Configure the CSN client

If users need to configure specific parameters for the CSN Client, they can customize the configuration using the exported Config field of the CSN Client object after its creation. This allows for configuring parameters such as proxy and maximum number of connections for the client.

Use a proxy

The following code snippet enables the client to access CSN service using a proxy:

1// import "github.com/baidubce/bce-sdk-go/services/csn"
2 // Create an CSN Client object
3AK, SK := <your-access-key-id>, <your-secret-access-key>
4ENDPOINT := "csn.baidubce.com"
5client, _ := csn.NewClient(AK, SK, ENDPOINT)
6 // Use the local port 8080 for the proxy
7client.Config.ProxyUrl = "127.0.0.1:8080"

Set network parameters

Users can configure network parameters using the following example code:

1// import "github.com/baidubce/bce-sdk-go/services/csn"
2AK, SK := <your-access-key-id>, <your-secret-access-key>
3ENDPOINT := "csn.baidubce.com"
4client, _ := csn.NewClient(AK, SK, ENDPOINT)
5 // Configure to not retry, default: Back Off retry
6client.Config.Retry = bce.NewNoRetryPolicy()
7 // Configure connection timeout to 30 seconds
8client.Config.ConnectionTimeoutInMillis = 30 * 1000

Configure options for generating signature strings

1// import "github.com/baidubce/bce-sdk-go/services/csn"
2AK, SK := <your-access-key-id>, <your-secret-access-key>
3ENDPOINT := "csn.baidubce.com"
4client, _ := csn.NewClient(AK, SK, ENDPOINT)
5 // Configure the HTTP request header Host for signing
6headersToSign := map[string]struct{}{"Host": struct{}{}}
7client.Config.SignOption.HeadersToSign = HeadersToSign
8 // Configure the validity period of the signature to 30 seconds
9client.Config.SignOption.ExpireSeconds = 30

Parameter description

When using the GO SDK to access CSN, the Config field of the created CSN Client object supports the following parameters, as shown in the table below:

ConfigMap name	Types	Meaning
Endpoint	string	Domain name for service requests
ProxyUrl	string	The proxy address for client requests
Region	string	Region for resource requests
UserAgent	string	User name, HTTP request’s User-Agent header
Credentials	*auth.BceCredentials	Authentication object for requests, divided into regular AK/SK and STS
SignOption	*auth.SignOptions	Options for authentication string signing
Retry	RetryPolicy	Retry policy for connections
ConnectionTimeoutInMillis	int	Connection timeout, in milliseconds, defaulting to 20 minutes

Description:

The Credentials is created using the auth.NewBceCredentials and auth.NewSessionBceCredentials functions. The former is used by default, while the latter is used for STS certification. See "Create a CSN client with STS" for details.
The SignOption field represents options when generating a signature string, as detailed in the table below:

Name	Types	Meaning
HeadersToSign	map[string]struct{}	HTTP headers used when generating the signature string
Timestamp	int64	Timestamp used in the generated signature string, defaulting to the value at the time of sending request
ExpireSeconds	int	Validity period of the signature string

Plain Text

1 Among configuration options, HeadersToSign defaults to `Host`, `Content-Type`, `Content-Length` and `Content-MD5`; TimeStamp is typically set to zero, indicating that the timestamp at the time of generating the certification string shall be used, and users generally shall not explicitly specify the value for this field; ExpireSeconds defaults to 1,800 seconds or 30 minutes.

The Retry field specifies the retry policy, currently supporting two types: NoRetryPolicy and BackOffRetryPolicy. By default, the latter is used. This retry policy specifies the maximum number of retries, the maximum retry duration, and the retry base. Retries increase exponentially based on the retry base multiplied by 2 until the maximum number of retries or the maximum retry duration is reached.

Exception handling

Install