Authentication-and-Authorization-Task: A JavaScript repository from Vengat-P

User Authentication and Authorization with Bearer Token Task Using Node js

Implement user authentication and authorization using Bearer tokens in a Node.js application with Express.js, Mongoose, and JWT. This application follow the MVC pattern and include API documentation.

Step 1

Initailize NPM by using npm init --y command in prombt then change scripts start for node index.js and type module and create index.js file.

Step 2

install required pacakges npm i expres ,cors ,dotenv ,nodemon ,bcrypt and JsonWebToken. Then add scripts for dev to automatic restart of nodemon index.js

Step 3
create folders and required javascript file in MVC Patterns its nothing but database, models,routers and controllers are in separate folders.MVC- Model Views Controllers .

Step 1

initalize express function and add middlewares like express.json and cors.then create defult route for home page of backend. then declare port and start the server using listen function.

Step 2

connect mongo DB using mongoose . make a async function with trycatch that returns our connection string with mongoose connect function.then call this function in index file before default route.

Step 3

need to create Schema structure using mongoose schema function . this structure format will refelcts our DB so create wisely . Each field should have type (String) and required(true).And email feild should be unique. then store Schema in variable name users to access further for this use mongoose model function.

Step 4

In user router file import express and declare (express.router) function to make custom routes for each operations. export default router function .then import this router file in index file with type of js file. then create custom route function for app and pass this (/api/auth/) and userRoute(this will replace all opertions end point).

Step 5

userRegister In user controller file first import userschema which is inlcude our schema structure and make an export function for userRegister . This function also trycatch model and parameters will be request and response. catch will give error message in json format.In try block declare variable with new function and call users as function from stored schema pass inside request.body .then our password need to be encrypt so by using bcrypt hash method we can hash the password. now store as newUser with new feature passing all fields. then to save newUser call save function.now in reponse with 200 status code pass json message and data(newUser).now goto user router file make router with post function and pass register path and userRegister function(automatcally controllers will import need to change last file in js type). for checking need to go to postman and give the localhost url with our custom routes.

Step 6

userLogin In user controller file crete a export function name is userLogin . now destructure the datas from client by using request.body method. and find the user from mongo db using findOne method (pass email because this feild is unique) and stored as user.now write validation if not a user return user not found. then check password with our hash password for this we need to use bcrypt compare method.then write validations for password if password not match return invalid password. now need to asign token for user for this we need to use jwt sign method and store that token then pass that into response.this will give token for login user.then go to user router page and use post method router and set path as /login and pass userLogin controller.now go to post man and check with customize api in end point use /login and enter email and password in json format in body with raw type you will get token.

Step 7

getuser for this function we need login token . to decode that we need user middleware function. in this middleware function get token by bearer token method and verify that in jwt method and store as decoded. now target req.user as decoded(this will give you the user id). this is middleware function so this will return next function call. now go to user controller make a export function name is getUser and use async,try catch method till catch block. in try block get user id from req.user and pass that as _id in findone method of mongo DB this will give user informations store this as user then pass this data in response.Now go to user router file and set get method and pass /getuser and getUser controller . now go to post man and check in authentication method bearer toke and paste the token(which is created from login end) . we can get user information details.