Upgrade ffmpeg-convert-audio sample to ES2017 syntax.

Author: nicolasgarnier

ffmpeg-convert-audio/README.md

@@ -10,25 +10,22 @@ The audio conversion is performed using ffmpeg. The audio is first downloaded lo
 
 The dependencies are listed in [functions/package.json](functions/package.json).
 
-
 ## Trigger rules
 
 The function triggers on upload of any file to your Firebase project's default Cloud Storage bucket.
 
-
 ## Deploy and test
 
 To deploy and test the sample:
 
- - Create a Firebase project on the [Firebase Console](https://console.firebase.google.com) and visit the **Storage** tab.
- - Get the code, for instance using `git clone https://github.com/firebase/functions-samples`
- - Enter the correct directory `cd functions-samples/ffmpeg-convert-audio`
- - Setup the CLI to use your Firebase project using `firebase use --add` and select your Firebase project
- - Deploy your project's code using `firebase deploy`
- - Go to the Firebase Console **Storage** tab and upload an audio. After a short time a converted audio with the same name but a `_output.flac` suffix will be created in the same folder (make sure you refresh the UI to see the new file).
+- Create a Firebase project on the [Firebase Console](https://console.firebase.google.com) and visit the **Storage** tab.
+- Get the code, for instance using `git clone https://github.com/firebase/functions-samples`
+- Enter the correct directory `cd functions-samples/ffmpeg-convert-audio`
+- Setup the CLI to use your Firebase project using `firebase use --add` and select your Firebase project
+- Deploy your project's code using `firebase deploy`
+- Go to the Firebase Console **Storage** tab and upload an audio. After a short time a converted audio with the same name but a `_output.flac` suffix will be created in the same folder (make sure you refresh the UI to see the new file).
 
 ## Notes
 
- - Take into account that the audio files produced should not exceed the size of the memory of your function.
- - The audio conversion could take a certain amount of time, increase the timeout of your function using the cloud functions webgui so the function can run for a longer time.
- 
+- Take into account that the audio files produced should not exceed the size of the memory of your function.
+- The audio conversion could take a certain amount of time, increase the timeout of your function using the cloud functions webgui so the function can run for a longer time.

ffmpeg-convert-audio/functions/.eslintrc.json

@@ -1,7 +1,7 @@
 {
   "parserOptions": {
     // Required for certain syntax usages
-    "ecmaVersion": 6
+    "ecmaVersion": 2017
   },
   "plugins": [
     "promise"

ffmpeg-convert-audio/functions/index.js

@@ -23,49 +23,21 @@ const fs = require('fs');
 const ffmpeg = require('fluent-ffmpeg');
 const ffmpeg_static = require('ffmpeg-static');
 
+// Makes an ffmpeg command return a promise.
 function promisifyCommand(command) {
   return new Promise((resolve, reject) => {
-    command
-        .on('end', () => {
-          resolve();
-        })
-        .on('error', (error) => {
-          reject(error);
-        })
-        .run();
-  });
-}
-
-/**
- * Utility method to convert audio to mono channel using FFMPEG.
- */
-function reencodeAsync(tempFilePath, targetTempFilePath) {
-  return new Promise((resolve, reject) => {
-    const command = ffmpeg(tempFilePath)
-        .setFfmpegPath(ffmpeg_static.path)
-        .audioChannels(1)
-        .audioFrequency(16000)
-        .format('flac')
-        .on('error', (err) => {
-          console.log('An error occurred: ' + err.message);
-          reject(err);
-        })
-        .on('end', () => {
-          console.log('Output audio created at', targetTempFilePath);
-        })
-        .save(targetTempFilePath);
+    command.on('end', resolve).on('error', reject).run();
   });
 }
 
 /**
  * When an audio is uploaded in the Storage bucket We generate a mono channel audio automatically using
  * node-fluent-ffmpeg.
  */
-exports.generateMonoAudio = functions.storage.object().onFinalize((object) => {
+exports.generateMonoAudio = functions.storage.object().onFinalize(async (object) => {
   const fileBucket = object.bucket; // The Storage bucket that contains the file.
   const filePath = object.name; // File path in the bucket.
   const contentType = object.contentType; // File content type.
-  const metageneration = object.metageneration; // Number of times metadata has been generated. New objects have a value of 1.
 
   // Exit if this is triggered on a file that is not an audio.
   if (!contentType.startsWith('audio/')) {
@@ -89,33 +61,26 @@ exports.generateMonoAudio = functions.storage.object().onFinalize((object) => {
   const targetTempFilePath = path.join(os.tmpdir(), targetTempFileName);
   const targetStorageFilePath = path.join(path.dirname(filePath), targetTempFileName);
 
-  return bucket.file(filePath).download({
-    destination: tempFilePath,
-  }).then(() => {
-    console.log('Audio downloaded locally to', tempFilePath);
-    // Convert the audio to mono channel using FFMPEG.
+  await bucket.file(filePath).download({destination: tempFilePath});
+  console.log('Audio downloaded locally to', tempFilePath);
+  // Convert the audio to mono channel using FFMPEG.
 
-    let command = ffmpeg(tempFilePath)
-        .setFfmpegPath(ffmpeg_static.path)
-        .audioChannels(1)
-        .audioFrequency(16000)
-        .format('flac')
-        .output(targetTempFilePath);
+  let command = ffmpeg(tempFilePath)
+      .setFfmpegPath(ffmpeg_static.path)
+      .audioChannels(1)
+      .audioFrequency(16000)
+      .format('flac')
+      .output(targetTempFilePath);
 
-    command = promisifyCommand(command);
+  await promisifyCommand(command);
+  console.log('Output audio created at', targetTempFilePath);
+  // Uploading the audio.
+  await bucket.upload(targetTempFilePath, {destination: targetStorageFilePath});
+  console.log('Output audio uploaded to', targetStorageFilePath);
 
-    return command;
-  }).then(() => {
-    console.log('Output audio created at', targetTempFilePath);
-    // Uploading the audio.
-    return bucket.upload(targetTempFilePath, {destination: targetStorageFilePath});
-  }).then(() => {
-    console.log('Output audio uploaded to', targetStorageFilePath);
+  // Once the audio has been uploaded delete the local file to free up disk space.
+  fs.unlinkSync(tempFilePath);
+  fs.unlinkSync(targetTempFilePath);
 
-    // Once the audio has been uploaded delete the local file to free up disk space.
-    fs.unlinkSync(tempFilePath);
-    fs.unlinkSync(targetTempFilePath);
-
-    return console.log('Temporary files removed.', targetTempFilePath);
-  });
+  console.log('Temporary files removed.', targetTempFilePath);
 });

ffmpeg-convert-audio/functions/package.json

@@ -20,5 +20,8 @@
     "deploy": "firebase deploy --only functions",
     "logs": "firebase functions:log"
   },
+  "engines": {
+    "node": "8"
+  },
   "private": true
 }