JavaScript

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 supports two operating environments: Node.js and browsers. This section uses Node.js as an example.

Prerequisites

• You have obtained API calling information. For details, see Preparations.
• You have installed the development tool and JavaScript development environment. For details, see Preparations.
  • After Node.js is installed, run the npm command to install the moment and moment-timezone modules.

    npm install moment --save
    npm install moment-timezone --save

  • You have installed the Node.js plug-in on IntelliJ IDEA. Otherwise, install it according to Figure 1.
    Figure 1 Installing the Node.js plug-in
    
• The browser must be Chrome 89.0 or later.

Obtaining the SDK

Old version: Log in to the ROMA Connect console, choose API Connect > API Calling > SDKs, and download the SDK.

New version: Log in to the ROMA Connect console, choose API Connect > Credentials > SDKs, and download the SDK.

The following shows the directory structure after the decompression.

Creating a Project

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

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

   Figure 2 New Project
   
2. Click ..., select the directory where the SDK is decompressed, and click Finish.
   Figure 3 Selecting the SDK directory after decompression
   
3. View the directory structure of the project.
   Figure 4 Directory structure of the new project
   
   • 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).
4. Click Edit Configurations.
   Figure 5 Edit Configurations
   
5. Click + and select Node.js.
   Figure 6 Selecting Node.js
   
6. Set JavaScript file to node_demo.js and click OK.
   Figure 7 Selecting node_demo.js
   

API Calling Example (Node.js)

1. Import signer.js to your project.

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

2. Generate a signer and enter the key and secret of the authorized credential. For details about how to obtain the information, see Obtaining API Calling Information.

   var sig = new signer.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. 
   sig.Key = process.env.HUAWEICLOUD_SDK_AK
   sig.Secret = process.env.HUAWEICLOUD_SDK_SK

3. Generate a request, and specify the method, request URL, and body. For details about how to obtain the information, see Obtaining API Calling Information.

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

4. Add the x-stage header to the request to specify the environment. Add other headers to sign as required.

   r.headers = { "x-stage":"RELEASE" }

5. 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)

6. 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)

To use a browser to access APIs, you need to register an API that supports the OPTIONS method. For details, see Creating an API in OPTIONS Mode. The response header contains Access-Control-Allow-* headers. You can add these headers by enabling CORS when creating an API.

1. 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>

2. Sign the request and access the API.

   var sig = new signer.Signer()
   sig.Key = process.env.HUAWEICLOUD_SDK_AK
   sig.Secret = process.env.HUAWEICLOUD_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
   });