Node.js demo

SDK installation

All official Alibaba Cloud SDKs for Node.js are in the @alicloud directory. The Node.js example for recording file recognition depends on @alicloud/nls-filetrans-2018-08-17. In the directory that contains the example file, run the following command to install the Node.js dependency:

npm install @alicloud/nls-filetrans-2018-08-17 --save

Call procedure

1. Create and initialize an Alibaba Cloud authentication object.

2. Set request parameters, submit a recording file recognition request, process the server-side response, and obtain the task ID.

3. Set the task ID as a query parameter and poll for the recognition result of the task.

Code example

• Download nls-sample-16k.wav. This recording is in Pulse-Code Modulation (PCM) format with a 16000 Hz sample rate. The model set in the console is the general-purpose model. If you use a different recording, you must specify the corresponding encoding format and sample rate, and set the corresponding model in the console. For more information about setting models, see Manage projects.

• Before you call the API, configure environment variables to load your access credentials. The environment variable names for the AccessKey ID, AccessKey secret, and AppKey are ALIYUN_AK_ID, ALIYUN_AK_SECRET, and NLS_APP_KEY.

'use strict';
const Client = require('@alicloud/nls-filetrans-2018-08-17');
function fileTrans(akID, akSecret, appKey, fileLink) {
    // The region ID. This is a static field.
    var ENDPOINT = 'http://filetrans.cn-shanghai.aliyuncs.com';
    var API_VERSION = '2018-08-17';
    /**
     * Create an Alibaba Cloud authentication client.
     */
    var client = new Client({
        accessKeyId: akID,     // To obtain an AccessKey ID and AccessKey secret, go to the console: https://ram.console.aliyun.com/manage/ak
        secretAccessKey: akSecret,
        endpoint: ENDPOINT,
        apiVersion: API_VERSION
    });
    /**
     * Submit a recording recognition request. Combine the request parameters into a JSON string as the value of task.
     * appkey: The AppKey of the project. To obtain an AppKey, go to the console: https://nls-portal.console.aliyun.com/applist
     * file_link: The recording to recognize.
     */
    var task = {
        appkey : appKey,
        file_link : fileLink,
        version : "4.0",        // If you are a new user, use version 4.0. If you are an existing user and want to keep the default version 2.0, comment out this parameter setting.
        enable_words : false     // Specifies whether to output word-level information. The default value is false. To enable this feature, you must set the version parameter to 4.0.
    };
    task = JSON.stringify(task);
    var taskParams = {
        Task : task
    };
    var options = {
            method: 'POST'
        };
    // Submit the recording recognition request and process the server-side response.
    client.submitTask(taskParams, options).then((response) => {
        console.log(response);
        // The status description (StatusText) in the server-side response.
        var statusText = response.StatusText;
        if (statusText != 'SUCCESS') {
            console.log('The recording recognition request failed!')
            return;
        }
        console.log('The recording recognition request succeeded!');
        // Get the TaskId of the recording recognition task to use for querying the result.
        var taskId = response.TaskId;
        /**
         * Use the TaskId as a query parameter to submit a request to query the recognition result.
         * Poll for the recognition result until the server-side returns a status of "SUCCESS", "SUCCESS_WITH_NO_VALID_FRAGMENT",
         * or an error description. Then, stop polling.
        */
        var taskIdParams = {
            TaskId : taskId
        };
        var timer = setInterval(() => {
            client.getTaskResult(taskIdParams).then((response) => {
                console.log('Query response for the recognition result:');
                console.log(response);
                var statusText = response.StatusText;
                if (statusText == 'RUNNING' || statusText == 'QUEUEING') {
                    // Continue polling. Note the polling interval.
                }
                else {
                    if (statusText == 'SUCCESS' || statusText == 'SUCCESS_WITH_NO_VALID_FRAGMENT') {
                        console.log('Recording recognized successfully:');
                        var sentences = response.Result;
                        console.log(sentences);
                    }
                    else {
                        console.log('Recording recognition failed!');
                    }
                    // Stop polling.
                    clearInterval(timer);
                }
            }).catch((error) => {
                console.error(error);
                // An exception occurred. Stop polling.
                clearInterval(timer);
            });
        }, 10000);
    }).catch((error) => {
        console.error(error);
    });
}
var akId = process.env.ALIYUN_AK_ID;
var akSecret = process.env.ALIYUN_AK_SECRET;
var appKey = process.env.NLS_APP_KEY;
var fileLink = 'https://gw.alipayobjects.com/os/bmw-prod/0574ee2e-f494-45a5-820f-63aee583045a.wav';
fileTrans(akId, akSecret, appKey, fileLink);