Short sentence recognition Node.js SDK usage guide-Intelligent Speech Interaction(ISI)-阿里云帮助中心

This topic describes how to use the Node.js SDK for short sentence recognition in Intelligent Speech Interaction. It covers how to install the SDK and provides code examples.

Prerequisites

Before you use the SDK, read the API reference. For more information, see the API reference.
Make sure that a Node.js and npm environment is installed and configured.
The SDK supports Node.js v14 and later.

Download and install

You can download and install the SDK.
Run the following command to download and install the SDK.
```
npm install alibabacloud-nls
```

You can import the SDK.

Use `require` or `import` in your code to import the SDK.

const Nls = require('alibabacloud-nls')
// Nls includes SpeechRecognition, SpeechTranscription, and SpeechSynthesizer.
// The following code shows how to import the SDK using import.
//import { SpeechRecognition } from "alibabacloud-nls"
//import { SpeechTranscription } from "alibabacloud-nls"
//import { SpeechSynthesizer } from "alibabacloud-nls"

Short sentence recognition

Class: SpeechRecognition

The SpeechRecognition class is used for short sentence recognition.

Constructor parameters:
Parameter
Type
Description
config
Object
The connection configuration object.

`config` object details:

Parameter	Type	Description
url	String	The service URL.
token	String	The access token. For more information, see Overview of how to obtain a token.
appkey	String	The AppKey of the project. To obtain an AppKey, go to the console.

defaultStartParams()

This method returns a default parameter object. In this object, `format` is set to PCM, `sample_rate` is set to 16000 Hz, and intermediate results, punctuation prediction, and Inverse Text Normalization (ITN) are enabled. After you obtain the default object, you can add or modify parameters as needed. For more information, see the parameter list in the API reference.

Parameters: None.

Return value:

An object with the following fields:

{
    "format": "pcm",
    "sample_rate": 16000,
    "enable_intermediate_result": true,
    "enable_punctuation_predition": true,
    "enable_inverse_text_normalization": true
}

on(which, handler)

This method sets an event callback.

Parameters:

Parameter	Type	Description
which	String	The event name.
handler	Function	The callback function.

The supported callback events are as follows:

Event name	Description	Number of callback function parameters	Callback function parameter description
started	Short sentence recognition starts.	1	String. The start message.
changed	Intermediate result of short sentence recognition.	1	String. The intermediate result message.
completed	Short sentence recognition is complete.	1	String. The completion message.
closed	The connection is closed.	0	None.
failed	An error occurred.	1	String. The error message.

Return value: None.

async start(param, enablePing, pingInterval)

This method starts a short sentence recognition task. The `param` object can be based on the return value of the `defaultStartParams()` method. For details about the parameters, see the API reference.

Parameters:

Parameter	Type	Description
param	Object	The parameters for short sentence recognition.
enablePing	Boolean	Specifies whether to automatically send ping requests to the cloud. The default value is false. true: Sends the data. false: The data is not sent.
pingInterval	Number	The interval for sending ping requests. The default value is 6000. Unit: milliseconds.

Return value: A Promise object. The `resolve` function is triggered when the `started` event occurs and includes the `started` message. The `reject` function is triggered if an error occurs and includes the exception information.

async close(param)

This method stops the short sentence recognition task.

Parameters:
Parameter
Type
Description
param
Object
The parameters to end the short sentence recognition task.
Return value:
A Promise object. The `resolve` function is triggered when the `completed` event occurs and includes the `completed` message. The `reject` function is triggered if an error occurs and includes the exception information.

shutdown()

This method forcibly disconnects the connection.

Parameters: None.
Return value: None.

sendAudio(data)

This method sends audio data. The audio format must be the same as the format specified in the parameters.

Parameters:
Parameter
Type
Description
data
Buffer
The binary audio data.
Return value: None.

Code example

"use strict"

const Nls = require("alibabacloud-nls")
const fs = require("fs")
const sleep = (waitTimeInMs) => new Promise(resolve => setTimeout(resolve, waitTimeInMs))

const URL = "wss://nls-gateway.cn-shanghai.aliyuncs.com/ws/v1"
const APPKEY = "Your Appkey"      // To obtain an AppKey, go to the console: https://nls-portal.console.aliyun.com/applist
const TOKEN = "Your Token"      // For more information about how to obtain a token, see https://help.aliyun.com/document_detail/450514.html

let audioStream = fs.createReadStream("test1.pcm", {
  encoding: "binary",
  highWaterMark: 1024
})
let b1 = []

audioStream.on("data", (chunk) => {
  let b = Buffer.from(chunk, "binary")
  b1.push(b)
})

audioStream.on("close", async ()=>{
  while (true) {
    let sr = new Nls.SpeechRecognition({
      url: URL,
      appkey:APPKEY,
      token:TOKEN
    })

    sr.on("started", (msg)=>{
      console.log("Client recv started:", msg)
    })

    sr.on("changed", (msg)=>{
      console.log("Client recv changed:", msg)
    })

    sr.on("completed", (msg)=>{
      console.log("Client recv completed:", msg)
    })

    sr.on("closed", () => {
      console.log("Client recv closed")
    })

    sr.on("failed", (msg)=>{
      console.log("Client recv failed:", msg)
    })

    try {
      await sr.start(sr.defaultStartParams(), true, 6000)
    } catch(error) {
      console.log("error on start:", error)
      continue
    }

    try {
      for (let b of b1) {
        if (!sr.sendAudio(b)) {
          throw new Error("send audio failed")
        }
        await sleep(20)
      }
    } catch(error) {
      console.log("sendAudio failed:", error)
      continue
    }

    try {
      console.log("close...")
      await sr.close()
    } catch(error) {
      console.log("error on close:", error)
    }
    await sleep(2000)
  }
})