将录制的 Twilio 音频发送到 Lex

目前我可以录制用户输入，将录制 URL 传递给所需的函数，并在本地下载音频文件。我试图对音频文件执行的操作是获取音频文件的缓冲区以发送到 Lex，或者将其转换为 Lex 需要的格式。

根据 AWS 文档，输入流参数值接受以下值：

var params = {
  botAlias: 'STRING_VALUE', /* required */
  botName: 'STRING_VALUE', /* required */
  contentType: 'STRING_VALUE', /* required */
  inputStream: new Buffer('...') || 'STRING_VALUE' || streamObject, /*required */
  userId: 'STRING_VALUE', /* required */
  accept: 'STRING_VALUE',
  requestAttributes: any /* This value will be JSON encoded on your behalf with JSON.stringify() */,
  sessionAttributes: any /* This value will be JSON encoded on your behalf with JSON.stringify() */
};
lexruntime.postContent(params, function(err, data) {
  if (err) console.log(err, err.stack); // an error occurred
  else     console.log(data);           // successful response
});

根据 twilio 文档，音频文件看起来非常灵活......

默认情况下，对 RecordingUrl 的请求将返回二进制 WAV 音频格式的录音。要请求 MP3 格式的录制，请将“.mp3”附加到 RecordingUrl。

我需要做什么才能以适合 Lex 的正确格式获取 twilio 录制的音频？这只是构建正确的 Lex 参数集的问题还是我需要事先进行一些音频转换？如果有帮助的话，我正在用 Node js 编写这个应用程序，如果有帮助的话，我可以添加更多代码。

我通过从 Twilio 下载文件作为 PCM 并稍微更改我的参数来解决这个问题。另外，由于 Twilio 处理记录动词的方式，我需要在等待记录状态回调 POST 时将呼叫转移到保持状态。我还向呼叫者发送一条短信，其中包含 Lex 的最终状态。

我用来下载文件的代码：

app.post('/processRecording', (request, response) => {   
    var https = require('https');
    var fs = require('fs');

    let callSID = request.body.CallSid;
    let url = request.body.RecordingUrl;

    var saveFile = new Promise(function(resolve, reject) {
       let fileName = callSID+ ".pcm";
       var file = fs.createWriteStream(fileName);
       var request = https.get(url, function(response) {
       response.pipe(file);
       resolve();
      });
    });

});

const accountSid = 'YOUR ACCOUNT SID';
const authToken = 'YOUR AUTH TOKEN';
const client = require('twilio')(accountSid, authToken);
//Once the file is downloaded, I then fetch the call from the hold state using this code:
saveFile.then(function(){
client.calls(callSID)
    .update({method: 'POST', url: '/updateCall'})
    .then(call => console.log(call.to))
    .done();
  });

我的 updateCall 端点如下所示：

app.post('/updateCall', (request, response) => {
    let lexruntime = new AWS.LexRuntime();
    let recordedFileName = request.body.CallSid + '.pcm';
    let toNumber = request.body.To;
    let fromNumber = request.body.From;
    let twiml = new Twilio.twiml.VoiceResponse();
    let lexFileStream = fs.createReadStream(recordedFileName);
    let sid = request.body.CallSid;
    var params = {
        botAlias: 'prod', /* required */
        botName: 'OrderFlowers', /* required */
        contentType: 'audio/lpcm; sample-rate=8000; sample-size-bits=16; channel-count=1; is-big-endian=false',
        accept: 'text/plain; charset=utf-8',
        userId: sid /* required */

    };

params.inputStream = lexFileStream;

lexruntime.postContent(params, function(err, data) {
    if (err) console.log(err, err.stack); // an error occurred
    else     console.log(data);           // successful response



    if (data.dialogState == "ElicitSlot" || data.dialogState == "ConfirmIntent" || data.dialogState == "ElicitIntent" ){
        twiml.say(data.message);
        twiml.redirect({
                        method: 'POST'
                        }, '/recordVoice');

            response.type('text/xml');
            response.send(twiml.toString());

    }
    else if (data.dialogState == "Fulfilled" ){
      twiml.say(data.message);
      response.type('text/xml');
      response.send(twiml.toString());
        client.messages.create({
           to: toNumber,
           from: fromNumber,
           body: data.message
        }).then(msg => {
        }).catch(err => console.log(err));
     }
    else{
        twiml.say(data.message);
        response.type('text/xml');
        response.send(twiml.toString());
    }

    });
});

recordVoice 端点实际上是一个 Twilio Serverless 函数，但我认为这就是它作为快速端点的样子：

 app.post('/recordVoice', (request, response) => {
    let twiml = new Twilio.twiml.VoiceResponse();
    twiml.record({
        action: '/deadAir',
        recordingStatusCallback: '/processRecording',
        trim: true,
        maxLength: 10,
        finishOnKey: '*'
    });
    twiml.say('I did not receive a recording');
    response.type('text/xml');
    response.send(twiml.toString());
});

/deadAir 端点也是一个 Twilio Serverless Function，但它看起来像这样：

app.post('/deadAir', (request, response) => {
    let twiml = new Twilio.twiml.VoiceResponse();
    twiml.pause({
        length: 60
    });
    response.type('text/xml');
    response.send(twiml.toString());
});