app.js

var createError = require("http-errors");
const express = require("express");
const cors = require("cors");
const path = require("path");
const cookieParser = require("cookie-parser");
const logger = require("morgan");
const bodyParser = require("body-parser");
const session = require("express-session");
const jwt = require("jsonwebtoken");


// Route files
var indexRouter = require('./routes');
var customerRouter = require('./routes/customerRouter');
var sellerRouter = require('./routes/sellerRouter');
var itemRouter = require('./routes/item');
var orderRouter = require('./routes/order');


const app = express();

// view engine setup
app.set("views", path.join(__dirname, "views"));
app.set("view engine", "jade");

// HTTP request logger middleware for node.js (morgan)
app.use(logger("dev"));

// This is to allow our api for cross-origin resource sharing (To communicate with front end. It is in another server)
app.use(cors( {
  origin: ["http://localhost:3000"],
  methods : ["GET", "POST","PUT","DELETE"], // The methods that we will use
  credentials: true // Allow cookie to be enabled
}));

// This is to allow our api for parsing json
// express.json() is a method inbuilt in express to recognize the incoming Request Object as a JSON Object
app.use(express.json({limit:'50mb'}));

// This is to allow our api to receive data from client app(front end)
app.use(express.urlencoded({ extended: false , limit:'50mb' }));
app.use(cookieParser());
app.use(bodyParser.urlencoded({ extended: true }));

//save cookie
app.use(session({
  key: "user",
  secret: "database_project",
  resave: false,
  saveUninitialized: false,
  cookie: { 
    expires: 1000 * 60 * 60 * 24, // After 24 hours
  }
}))

// Built in middleware to serve static files such as images, CSS files, and JavaScript files (express.static)
app.use(express.static(path.join(__dirname, "public")));



// Redirect to routes
app.use('/', indexRouter);
app.use('/customer', customerRouter);
app.use('/seller', sellerRouter);
app.use('/items', itemRouter);
app.use('/orders', orderRouter);

// catch 404 and forward to error handler
app.use(function (req, res, next) {
  next(createError(404));
});

// error handler
app.use(function (err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get("env") === "development" ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render("error");
});

// This allows us to use this file in anywhere else by importing
module.exports = app;