Go

Scenarios

To use Go to call an API through app authentication, obtain the Go SDK, create a new project, and then call the API by referring to the API calling example.

This section uses IntelliJ IDEA 2022.2.1 as an example.

Prerequisites

• You have obtained API calling information. For details, see Preparation.
• You have installed Go 1.14 or a later version. If not, download the Go installation package from the official Go website and install it.
• You have installed IntelliJ IDEA 2022.2.1 or a later version. If not, download the installation package from the official IntelliJ IDEA website and install it.
• You have installed the Go plug-in on IntelliJ IDEA. If not, install the Go plug-in according to Figure 1.
  Figure 1 Installing the Go plug-in
  

Obtaining the SDK

Log in to the APIG console, and download the SDK on the SDKs page by referring to section "SDKs" in the API Gateway User Guide.

Alternatively, download the latest SDK version. Then obtain the ApiGateway-go-sdk.zip package. The following table shows the files decompressed from the package.

Creating a Project

1. Start IntelliJ IDEA and choose File > New > Project.

   In the displayed New Project dialog box, set Name to the name of the folder in the SDK package, Location to the decompression path of the folder, Language to Go, and click Create.

   Figure 2 Go
   

2. View the directory structure shown in the following figure.
   Figure 3 Directory structure of the new project go
   

   Modify the parameters in sample code demo.go as required. For details about the sample code, see API Calling Example.

API Calling Example

1. Import the Go SDK (signer.go) to the project.

   import "apig-sdk/go/core"

2. Generate a new signer and enter the AppKey and AppSecret.
   1. In this example, the AK and SK stored in the environment variables are used. Specify the environment variables HUAWEICLOUD_SDK_AK and HUAWEICLOUD_SDK_SK in the local environment first. The following uses Linux as an example to describe how to set the obtained AK/SK as environment variables.
      1. Open the terminal and run the following command to open the environment variable configuration file:

         vi ~/.bashrc

      2. Set environment variables, save the file, and exit the editor.

         export HUAWEICLOUD_SDK_AK="Obtained AK"
         export HUAWEICLOUD_SDK_SK="Obtained SK"

      3. Run the following command to apply the modification:

         source ~/.bashrc

   2. Generate a new signer and enter the configured environment variables.

      s := core.Signer{
      // Directly writing AK/SK in code is risky. For security, encrypt your AK/SK and store them in the configuration file or environment variables.
      // In this example, the AK/SK are stored in environment variables for identity authentication. Before running this example, set environment variables HUAWEICLOUD_SDK_AK and HUAWEICLOUD_SDK_SK.
              Key: os.Getenv("HUAWEICLOUD_SDK_AK"),
              Secret: os.Getenv("HUAWEICLOUD_SDK_SK"),
      }

3. Generate a new request, and specify the domain name, method, request URL, query parameters, and body.

   r, _ := http.NewRequest("POST", "http://c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com/api?a=1&b=2",
                            ioutil.NopCloser(bytes.NewBuffer([]byte("foo=bar"))))

4. Add the x-stage header to the request to specify an environment name. Add other headers to be signed as necessary.

   r.Header.Add("x-stage", "RELEASE")

5. Execute the following function to add the X-Sdk-Date and Authorization headers for signing:

   s.Sign(r)

6. Access the API and view the access result.

   resp, err := http.DefaultClient.Do(r)
   body, err := ioutil.ReadAll(resp.Body)