JavaScript

Scenarios

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

This section uses IntelliJ IDEA 2018.3.5 as an example to describe how to set up a Node.js development environment.

Preparing the Environment

You have obtained the domain name, request URL, and request method of the API to be called, and the AppKey and AppSecret of the App for calling the API. For more information, see Preparation.
You have installed the Node.js programming language. If not, download the Node.js installation package from the official Node.js website and install it.
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 IntelliJ IDEA. If not, download IntelliJ IDEA from the official IntelliJ IDEA website and install it.
You have installed the Node.js plug-in on IntelliJ IDEA. If not, install the Python plug-in according to Figure 1.
Figure 1 Installing the Node.js plug-in

Obtaining the SDK

Log in to the DataArts Studio console.
Click DataArts DataService.
In the navigation pane, choose DataArts DataService Exclusive > SDKs.
On the SDKs page, download the SDK package.

Verify integrity of the SDK package. In Windows, open the CLI and run the following command to generate the SHA-256 value of the downloaded SDK package. In the command, D:\java-sdk.zip is an example local path and name of the SDK package. Replace it with the actual value.

certutil -hashfile D:\java-sdk.zip SHA256

The following is an example command output:

SHA-256 hash value of D:\java-sdk.zip
a7c0195ebf297f29ab0065da16d7e84f14911de177e6e0c8dbadf3464d12b75f
CertUtil: -hashfile command executed.

Compare the SHA-256 value of the downloaded SDK package with that provided in the following table. If they are the same, no tampering or packet loss occurred during the package download.

Language	SHA-256 Value of the SDK Package
Java	a7c0195ebf297f29ab0065da16d7e84f14911de177e6e0c8dbadf3464d12b75f
Go	caf22350181a4ecd49dc0d3f56097b10c1794792adae407140950be4ed9b6771
Python	c80b9ef282fc88d3fb16db4cb9d7525d3db71f7989782ed0b636920ea2fadb93
C#	b0e69ef60a561c54c1b86c3447ca855088a1fa2a672fbfba618aaf56b2841e8a
JavaScript	c64e595651de079766e446ce2c3262013256f81683bb9434bee27bed3a4caf01
PHP	e2eba2cae72aea794edb4057ed8eb7cb82f0dbaccabf9c5539694a7a7a9f3c89
C++	c173f59d816aba53f47750cf5ffdc65cc345b1613974b3d2a545ace48787f577
C	e4f22beb7b132fe6e57c9de79f596c3ff830228cd7221b02ca96198e501c642c
Android	d6c3032801ac88cf8cbc51f64d42457174447c8d159f34a187c036913b31ea2b

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
js\moment.min.js
js\moment-timezone-with-data.min.js
licenses\license-crypto-js	Third-party licenses
licenses\license-moment
licenses\license-moment-timezone
licenses\license-node

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 New Project
Click ..., select the directory where the SDK is decompressed, and click Finish.

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

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).
Click Edit Configurations.

Figure 5 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 http = require('http')

Generate a new signer and enter the AppKey and AppSecret.

      
           var sig = new signer.Signer()
sig.Key = "4f5f626b-073f-402f-a1e0-e52171c6100c"
sig.Secret = "******"

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

      
           var r = new signer.HttpRequest("POST", "{apig-endpoint}/app1?a=1");
r.body = '{"a":1}'

Add a header to the request. The header contains specific parameters. Add other headers to be signed as necessary.
1

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

Execute the following function to generate HTTP(s) request parameters, and add the X-Sdk-Date and Authorization headers for signing the request: Then, add the x-Authorization header to the request. The value of the x-Authorization header is the same as that of the Authorization header.

      
           var opt = sig.Sign(r)
opt.headers["x-Authorization"] = opt.headers["Authorization"]

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(opt, 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()