AWS Polly with Node JS

Hi,

I got a chance to work with AWS Polly and i am willing to share my interesting experiences.

Amazon Polly (Text-to-Speech) implementation with Node JS

What is Amazon Polly?

Amazon Polly is a mechanism that gives text-to-speech cloud service. Amazon Polly supports multiple languages and includes a variety of voices.

Benefits:

• High quality
• Low latency
• Support for different voices
• Cost effective
• Cloud based solution

 

Architecture of AWS Polly implementation.

 

Coding level implementation

 

Node js Function

//initilaization

var fs = require(‘fs’);
var AWS = require(‘aws-sdk’);
require(‘ auth-config-polly.js’);

function PollyImplemetation(req, callback) {
var msg = req.text;
var id = req.id

var polly = new AWS.Polly();
var descParams = {
LanguageCode: ‘en-US’
};

polly.describeVoices(descParams, function (err, data) {
if (err) {
console.log(err);
callback(null)
} else {
var thevoiceId = data.Voices[0].Id;
// synthesizeSpeech
var textMsg = msg;
var speechParams = {
“OutputFormat”: ‘mp3’,
“VoiceId”: thevoiceId,
“Text”: textMsg,
“SampleRate”: ‘22050’,
“TextType”: ‘text’
};
polly.synthesizeSpeech(speechParams, function (err, data) {
if (err) {
console.log(err);
callback(null)
} else {
fs.writeFile(‘./public/ ‘ + id + ‘.mp3’, data.AudioStream, function (err) {
console.log(‘file writing in local ‘);
if (err) {

console.log(err);
callback(null)
} else {
//uploading to S3 bucket process
var fileStream = fs.createReadStream(‘./public/’ + id + “” + ‘.mp3’);
fileStream.on(‘error’, function (err) {
if (err) {
console.log(err);
callback(null)
}
});
fileStream.on(‘open’, function () {
var s3 = new AWS.S3();
s3.putObject({
Bucket: ‘mp3bucketname’,
Key: ‘mp3/’ + id + ‘.mp3’,
ACL: ‘public-read’,
Body: fileStream
}, function (err) {
if (err) {
console.log(err);
callback(null)
} else {
callback(id + ‘.mp3’)
}
});
});

}
});
}
});
}

});
}

 

 

auth-config-polly.js

AWS.config.loadFromPath(‘config_polly.json’);

 

config_polly.json

{
“accessKeyId”: “XXXXXXXXXXX”,
“accessKey”: “XXXXXXXCCYYYYYYYYYY”,
“region”: “XXXXXXXXXXX”,
“version”: “latest”
}

 

How to call 

var reg = [{
“id”: “123”,
“value”: “Test first text to speech”,
}, {
“id”: “1234”,
“value”: “Second text to speech”,
}];

PollyImplemetation(req, function() {

 

});