Middlewares - nuthanc/microservice GitHub Wiki

Middlewares

• Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle
• Middlewares in the App in common/src/middlewares
• Examples of middleware

// current-user.ts
import { Request, Response, NextFunction } from 'express';
import jwt from 'jsonwebtoken';

interface UserPayload {
  id: string;
  email: string;
}

// Making changes to existing Type definition
declare global {
  namespace Express {
    interface Request {
      currentUser?: UserPayload;
    }
  }
}

export const currentUser = (
  req: Request,
  res: Response,
  next: NextFunction
) => {
  if (!req.session?.jwt) {
    return next();
  }

  try {
    const payload = jwt.verify(
      req.session.jwt,
      process.env.JWT_KEY!
    ) as UserPayload;
    req.currentUser = payload;
  } catch (err) {}

  next();
};

// require-auth.ts
import { Request, Response, NextFunction } from 'express';
import { NotAuthorizedError } from '../errors/not-authorized-error';

export const requireAuth = (
  req: Request,
  res: Response,
  next: NextFunction
) => {
  if (!req.currentUser) {
    throw new NotAuthorizedError();
  }

  next();
};

• Use of middleware

// routes current-user.ts
import express from 'express';

import { currentUser } from '@rztickets/common';

const router = express.Router();

router.get('/api/users/currentuser', currentUser, (req, res) => {
  res.send({ currentUser: req.currentUser || null });
});

export { router as currentUserRouter };