使用Google Cloud Storage将来自Google Text-to-Speech的音频文件保存到Firebase Storage？

Question

我们正在尝试使用Google Cloud Function从Google Text-to-Speech获取音频文件并将其保存到Firebase Storage。Google Text-to-Speech的文档展示了如何获取音频文件并将其保存在本地：

// Performs the Text-to-Speech request
const [response] = await client.synthesizeSpeech(request);
// Write the binary audio content to a local file
const writeFile = util.promisify(fs.writeFile);
await writeFile('output.mp3', response.audioContent, 'binary');
console.log('Audio content written to file: output.mp3');

这会导致一个错误信息Error: EROFS: read-only file system。Google Cloud Storage不允许在本地写入文件。

使用Firebase Storage的bucket.upload()存在一些问题：

   const destinationPath = 'Audio/Spanish' + filename.ogg;
   // Performs the Text-to-Speech request
   const [response] = await client.synthesizeSpeech(request);
   // response.audioContent is the downloaded file
   await bucket.upload(response.audioContent, {
      destination: destinationPath
   ));

错误信息为 TypeError: Path must be a string 。bucket.upload() 的第一个参数是要上传到您的存储桶中的文件的完全限定路径，并且应该是字符串，所以 response.audioContent 不起作用。

bucket.upload() 的文档建议我们将路径放在 destination: destinationPath 中作为 Firebase 存储位置。这正确吗？

我们如何将来自 Google 文字转语音（response.audioContent）的音频文件保存为字符串，以便 bucket.upload() 可以访问？或者我们应该使用其他东西来替代 bucket.upload() 吗？

以下是我们的完整云函数：

exports.Google_T2S = functions.firestore.document('Users/{userID}/Spanish/T2S_Request').onUpdate((change, context) => {
  if (change.after.data().word != undefined) {

    // Performs the Text-to-Speech request
    async function test() {
      try {
        const word = change.after.data().word; // the text
        const longLanguage = 'Spanish';
        const audioFormat = '.mp3';
        // copied from https://cloud.google.com/text-to-speech/docs/quickstart-client-libraries#client-libraries-usage-nodejs
        const fs = require('fs');
        const util = require('util');
        const textToSpeech = require('@google-cloud/text-to-speech'); // Imports the Google Cloud client library
        const client = new textToSpeech.TextToSpeechClient(); // Creates a client

        let myWordFile = word.replace(/ /g,"_"); // replace spaces with underscores in the file name
        myWordFile = myWordFile.toLowerCase(); // convert the file name to lower case
        myWordFile = myWordFile + audioFormat; // append .mp3 to the file name;

        // copied from https://cloud.google.com/blog/products/gcp/use-google-cloud-client-libraries-to-store-files-save-entities-and-log-data
        const {Storage} = require('@google-cloud/storage');
        const storage = new Storage();
        const bucket = storage.bucket('myProject-cd99d.appspot.com');
        const destinationPath = 'Audio/Spanish/' + myWordFile;

        const request = { // Construct the request
          input: {text: word},
          // Select the language and SSML Voice Gender (optional)
          voice: {languageCode: 'es-ES', ssmlGender: 'FEMALE'},
          // Select the type of audio encoding
          audioConfig: {audioEncoding: 'MP3'},
        };

        const [response] = await client.synthesizeSpeech(request);
        // Write the binary audio content to a local file
        const writeFile = util.promisify(fs.writeFile);
        await writeFile('output.mp3', response.audioContent, 'binary');
        console.log('Audio content written to file: output.mp3')
        // response.audioContent is the downloaded file

        await bucket.upload(response.audioContent, {
          destination: destinationPath
        });
      }
      catch (error) {
        console.error(error);
      }
    }
    test();
  } // close if
  return 0; // prevents an error message "Function returned undefined, expected Promise or value"
});

- Thomas David Kehoe

Answer 1

file.save()是答案。 util.promisify是不必要的，并且会导致关于original的错误消息。 这是完成的云函数：

const functions = require('firebase-functions');

// // Create and Deploy Your First Cloud Functions
// // https://firebase.google.com/docs/functions/write-firebase-functions
//
// exports.helloWorld = functions.https.onRequest((request, response) => {
//  response.send("Hello from Firebase!");
// });

async function textToSpeechRequest() {
    try 
              {
                const word = change.after.data().word; // the text
                const longLanguage = 'Spanish';
                const audioFormat = '.mp3';
                // copied from https://cloud.google.com/text-to-speech/docs/quickstart-client-libraries#client-libraries-usage-nodejs
                const util = require('util');
                const textToSpeech = require('@google-cloud/text-to-speech'); // Imports the Google Cloud client library
                const client = new textToSpeech.TextToSpeechClient(); // Creates a client

                let myWordFile = word.replace(/ /g,"_"); // replace spaces with underscores in the file name
                myWordFile = myWordFile.toLowerCase(); // convert the file name to lower case
                myWordFile = myWordFile + audioFormat; // append .mp3 to the file name;

                // copied from https://cloud.google.com/blog/products/gcp/use-google-cloud-client-libraries-to-store-files-save-entities-and-log-data
                const { Storage } = require('@google-cloud/storage');
                const storage = new Storage();
                const bucket = storage.bucket('myProject-cd99d.appspot.com');
                var file = bucket.file('Audio/Spanish/' + myWordFile);

                const request = { // Construct the request
                  input: {text: word},
                  // Select the language and SSML Voice Gender (optional)
                  voice: {languageCode: 'es-ES', ssmlGender: 'FEMALE'},
                  // Select the type of audio encoding
                  audioConfig: {audioEncoding: 'MP3'},
                };

                const options = { // construct the file to write
                  metadata: {
                    contentType: 'audio/mpeg',
                    metadata: {
                      source: 'Google Text-to-Speech'
                    }
                  }
                };

                // copied from https://cloud.google.com/text-to-speech/docs/quickstart-client-libraries#client-libraries-usage-nodejs
                const [response] = await client.synthesizeSpeech(request);
                // Write the binary audio content to a local file
                // response.audioContent is the downloaded file
                return await file.save(response.audioContent, options)
                .then(() => {
                  console.log("File written to Firebase Storage.")
                  return;
                })
                .catch((error) => {
                  console.error(error);
                });
            } // close try
            catch (error) {
              console.error(error);
            } // close catch
    } // close async function declaration
  
    exports.Google_T2S = functions.firestore.document('Users/{userID}/Spanish/T2S_Request').onUpdate((change, context) => {
          if (change.after.data().word !== undefined) 
          {
            textToSpeechRequest();
          } // close if
      
      
    }); // close Google_T2S

我们遇到了一个错误 TypeError: [ERR_INVALID_ARG_TYPE]: The "original" argument must be of type function at Object.promisify。这个错误似乎不会影响云函数的运行。

再次强调一下没有成功的尝试，fs.createWriteStream 没有成功，因为 Google Cloud Functions 无法处理 Node 文件系统 命令。相反，Google Cloud Functions 有自己的 方法 来包装 Node 文件系统命令。bucket.upload() 可以将本地文件上传到存储桶，但本地文件的路径必须是字符串，不能是来自 API 的缓冲区或流。file.save() 被文档化为：

向文件中写入任意数据。

这是一个方便的方法，它包装了 File#createWriteStream。

那就是我想要的！关于我的数据，有一件事是任意的。或者说本质上是相反的。之后我们只需要整理一下contentType（不是mp3，而是audio/mpeg）和文件路径。

- Thomas David Kehoe

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为什么 const bucket.. 被注释掉了？ - arielhasidim