Twilio app for repeating everything someone has said once they say the word "repeat".

twilio-repeat.js

const WebSocket = require("ws");
const express = require("express");
const app = express();
const server = require("http").createServer(app);
const wss = new WebSocket.Server({ server });

const path = require("path");
const fs = require("fs");

require("dotenv").config();

const speech = require("@google-cloud/speech");
const client = new speech.SpeechClient();
const request = {
  config: {
    encoding: "MULAW",
    sampleRateHertz: 8000,
    languageCode: "en-US",
  },
  interimResults: true
};

wss.on("connection", function connection(ws) {
  console.log("New Connection Initiated");

  let recognizeStream = null;
  let recording = Buffer.from([]);
  let repeated = false;

  ws.on("message", function incoming(message) {
    const msg = JSON.parse(message);
    switch (msg.event) {
      case "connected":
        console.log(`A new call has connected.`);
        break;
      case "start":
        const streamSid = msg.streamSid;
        console.log(`Starting Media Stream ${streamSid}`);
        recognizeStream = client
          .streamingRecognize(request)
          .on("error", console.error)
          .on("data", (data) => {
            const transcript = data.results[0].alternatives[0].transcript;
            console.log(transcript);
            wss.clients.forEach((client) => {
              if (client.readyState === WebSocket.OPEN) {
                if (transcript.toLowerCase().includes("repeat") && !repeated) {
                  repeated = true;
                  client.send(
                    JSON.stringify({
                      event: "media",
                      streamSid,
                      media: {
                        payload: Buffer.from(recording).toString("base64"),
                      },
                    })
                  );
                  client.send(
                    JSON.stringify({
                      event: "mark",
                      streamSid,
                      mark: {
                        name: "repeat",
                      },
                    })
                  );
                }

                client.send(
                  JSON.stringify({
                    event: "interim-transcription",
                    text: transcript,
                  })
                );
              }
            });
          });
        break;
      case "media":
        let payload = msg.media.payload;
        let decoded = Buffer.from(payload, "base64");
        recording = Buffer.concat([recording, decoded]);
        recognizeStream.write(msg.media.payload);
        break;
      case "stop":
        console.log(`Call Has Ended`);
        recognizeStream.destroy();
        let filename = "audio.pcm";
        fs.writeFileSync(filename, recording);
        break;
    }
  });
});

app.use(express.static("public"));

app.get("/", (req, res) => res.sendFile(path.join(__dirname, "/index.html")));

app.post("/", (req, res) => {
  res.set("Content-Type", "text/xml");
  res.send(`
    <Response>
      <Say>Let's go!</Say>
      <Connect>
        <Stream url="wss://${req.headers.host}/"/>
      </Connect>
      <Pause length="60" />
    </Response>
  `);
});

console.log("Listening on Port 8080");
server.listen(8080);