将IBM Watson Text-to-Speech与Firebase Cloud Functions结合使用？

Question

我正在尝试使用set up a Firebase Cloud Function来访问IBM Watson Text- to -Speech。问题是将返回的音频文件写入我的Firestore数据库。

这个测试返回工作的语音列表，将响应记录到函数日志中：

exports.test = functions.firestore.document('IBM_Watson_Token/Test_Value').onUpdate((change, context) => {
  var textToSpeech = new TextToSpeechV1({
    username: 'groucho',
    password: 'swordfish'
  });

  return textToSpeech.listVoices(null, function(error, voices) {
    if (error) {
      console.log(error);
    } else {
      console.log(JSON.stringify(voices, null, 2));
    }
  });
});

以下是用于返回音频文件并将其写入服务器的documentation示例节点代码：

var TextToSpeechV1 = require('watson-developer-cloud/text-to-speech/v1');
var fs = require('fs');

var textToSpeech = new TextToSpeechV1({
  username: '{username}',
  password: '{password}'
});

var synthesizeParams = {
  text: 'Hello world',
  accept: 'audio/wav',
  voice: 'en-US_AllisonVoice'
};

// Pipe the synthesized text to a file.
textToSpeech.synthesize(synthesizeParams).on('error', function(error) {
  console.log(error);
}).pipe(fs.createWriteStream('hello_world.wav'));

Firebase不允许使用fs将文件写入服务器，您必须写入Firestore数据库。我更改了示例代码的最后一行，使用promise将其写入Firestore：

exports.test = functions.firestore.document('IBM_Watson_Token/Test_Value').onUpdate((change, context) => {
  var textToSpeech = new TextToSpeechV1({
    username: 'groucho',
    password: 'swordfish'
  });

  var synthesizeParams = {
    text: 'Hello world',
    accept: 'audio/wav',
    voice: 'en-US_AllisonVoice'
  };

    return textToSpeech.synthesize(synthesizeParams).on('error', function(error) {
    console.log(error);
  }).then(function (audiofile) {
    admin.firestore().collection('IBM_Watson_Token').doc('hello_world').set({
      'audiofile': audiofile
    })
  })
  .catch(function (error) {
    console.log(error);
  });
});

错误消息是

TypeError: textToSpeech.synthesize(...).on(...).then is not a function

如何将从Watson返回的音频文件保存到Firestore？

Answer 1

这是因为synthesize方法没有返回promise。您将需要使用一个回调构造，如下所示

    textToSpeech.synthesize(params, function (err, body, response) {
      if (err) {
        ...
      } else {
        // body is the audio
        ... 
      }
    });