server.js

const express = require("express");
const app = express();
const mongoose = require("mongoose");
const bodyParser = require("body-parser");
const server = require(`http`).Server(app);
const io = require("socket.io")(server);
const compression = require("compression");

const doctorRoutes = require("./routes/doctorRoutes");
const patientRoutes = require("./routes/patientRoutes");
const requestRoutes = require("./routes/requestRoutes");

//CORS
app.use((req, res, next) => {
  res.append("Access-Control-Allow-Origin", ["*"]);
  res.append("Access-Control-Allow-Methods", "GET,PUT,POST,DELETE");
  res.append("Access-Control-Allow-Headers", "Content-Type, Authorization");
  next();
});

// COMPRESSION --> GZIP
app.use(compression());

// Body-parser
app.use(bodyParser.json());

app.use(doctorRoutes);
app.use(patientRoutes);
app.use(requestRoutes);

// Mongo Connection
mongoose.connect(
  "mongodb+srv://hac:knownsense@cluster0.zmc44.mongodb.net/<dbname>?retryWrites=true&w=majority",
  {
    useNewUrlParser: true,
    useCreateIndex: true,
    useUnifiedTopology: true,
  }
);

mongoose.connection.on("connected", () => {
  console.log("Connected to mongo instance");
});
mongoose.connection.on("error", (err) => {
  console.error("Error connenting to mongo", err);
});

// For Production
if (process.env.NODE_ENV === "production") {
  app.use(express.static("client/build"));

  const path = require("path");
  app.get("*", (req, res) => {
    res.sendFile(path.resolve(__dirname, "client", "build", "index.html"));
  });
}

//Socket Com
io.on("connection", (socket) => {
  socket.on("join-room", (roomId, userId) => {
    socket.join(roomId);
    socket.to(roomId).broadcast.emit("user-connected", userId);

    socket.on("disconnect", () => {
      socket.to(roomId).broadcast.emit("user-disconnected", userId);
    });
  });
});

const PORT = process.env.PORT || 5000;

server.listen(PORT, () => {
  console.log(`Server Started on PORT ${PORT}`);
});