JavaScript

Updated on 2025-02-19 GMT+08:00

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Scenarios

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

The JavaScript SDK can run in a Node.js or browser environment.

This section describes the procedure of using IntelliJ IDEA 2018.3.5 to establish a Node.js environment. It also provides examples of calling APIs using a browser.

Preparing the Environment

You have obtained API calling information. For details, see Preparation.
You have installed Node.js 15.10.0 or a later version. If not, download it from the official Node.js website and install it.
You have installed IntelliJ IDEA 2018.3.5 or a later version. If not, download it from the official IntelliJ IDEA website and install it.
You have installed the Node.js plug-in on IntelliJ IDEA. If not, install the Node.js plug-in according to Figure 1.
Figure 1 Installing the Node.js plug-in

Obtaining the SDK

On the APIG console, choose Help Center > Using SDKs, and download the SDK of the desired language.

Then obtain the ApiGateway-javascript-sdk.zip package. The following table shows the files decompressed from the package.

Name	Description
signer.js	SDK code
node_demo.js	Node.js sample code
demo.html	Browser sample code
demo_require.html	Browser sample code (loaded using require)
test.js	Test case
js\hmac-sha256.js	Dependencies
licenses\license-crypto-js	Third-party licenses
licenses\license-node	Third-party licenses

Creating a Project

Start IntelliJ IDEA and choose File > New > Project.

In the New Project dialog box, choose Static Web and click Next.

Figure 2 Static Web
Click ..., select the directory where the SDK is decompressed, and click Finish.

Figure 3 Selecting the SDK directory of JavaScript after decompression
View the directory structure shown in the following figure.

Figure 4 Directory structure of the new project JavaScript
- node_demo.js: Sample code in Node.js. Modify the parameters in the sample code as required. For details about the sample code, see API Calling Example (Node.js).
- demo.html: Browser sample code. Modify the parameters in the sample code as required. For details about the sample code, see API Calling Example (Browser).
Click Edit Configurations.

Figure 5 Click Edit Configurations
Click + and select Node.js.

Figure 6 Selecting Node.js
Set JavaScript file to node_demo.js and click OK.

Figure 7 Selecting node_demo.js

API Calling Example (Node.js)

Import signer.js to your project.

var signer = require('./signer')
var https = require('https')

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 CLOUD_SDK_AK and CLOUD_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 CLOUD_SDK_AK="Obtained AK"
export CLOUD_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.
```
var sig = new signer.Signer()
sig.Key = process.env.CLOUD_SDK_AK
sig.Secret = process.env.CLOUD_SDK_SK
```

Generate a request, and specify the method, request URI, and request body.

var r = new signer.HttpRequest("POST", "c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com/app1?a=1");
r.body = '{"a":1}'

Add the x-stage header to the request to specify an environment name. Add other headers to be signed as necessary.
```
r.headers = { "x-stage":"RELEASE" }
```
Execute the following function to generate HTTP(s) request parameters, and add the X-Sdk-Date and Authorization headers for signing the request:
```
var opts = sig.Sign(r)
```

Access the API and view the access result. If you access the API using HTTPS, change http.request to https.request.

var req=http.request(opts, function(res){
        console.log(res.statusCode)  
        res.on("data",	function(chunk){
		console.log(chunk.toString())
	})
})
req.on("error",function(err){
	console.log(err.message)
})
req.write(r.body)
req.end()

API Calling Example (Browser)

The browser restricts the initiation of cross-domain requests from page scripts. Therefore, before accessing an API, you need to create a CORS policy on the APIG console to allow the browser to send XMLHttpRequest requests to the server in a different domain, and bind the policy to the API.

For details about how to create a CORS policy, see "CORS" in the API Gateway User Guide.
Figure 8 Example for creating a CORS policy

Import signer.js and dependencies to the HTML page.

<script src="js/hmac-sha256.js"></script>
<script src="js/moment.min.js"></script>
<script src="js/moment-timezone-with-data.min.js"></script>
<script src='signer.js'></script>

Sign the request and access the API.

In this example, the AK and SK stored in the environment variables are used. Specify the environment variables CLOUD_SDK_AK and CLOUD_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 CLOUD_SDK_AK="Obtained AK"
export CLOUD_SDK_SK="Obtained SK"
```
3. Run the following command to apply the modification:
  source ~/.bashrc

Enter the configured environment variables for signature and access.

var sig = new signer.Signer()
sig.Key = getenv('CLOUD_SDK_AK')
sig.Secret = getenv('CLOUD_SDK_SK')
var r= new signer.HttpRequest()
r.host = "c967a237-cd6c-470e-906f-a8655461897e.apigw.exampleRegion.com"
r.method = "POST"
r.uri = "/app1"
r.body = '{"a":1}'
r.query = { "a":"1","b":"2" }
r.headers = { "Content-Type":"application/json" }
var opts = sig.Sign(r)
var scheme = "https"
$.ajax({
	type: opts.method,
	data: req.body,
	processData: false,
	url: scheme + "://" + opts.hostname + opts.path,
	headers: opts.headers,
	success: function (data) {
		$('#status').html('200')
		$('#recv').html(data)
	},
	error: function (resp) {
		if (resp.readyState === 4) {
			$('#status').html(resp.status)
			$('#recv').html(resp.responseText)
		} else {
			$('#status').html(resp.state())
		}
	},
	timeout: 1000
});

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