User Registration Notes

Objectives

Explain what a cryptographic hash function is.
Explain why a cryptographic hash function is important.
Explain what bcrypt is.
Register a user with a hashed password.

Explain what a cryptographic hash function is.

Turn to your neighbor and explain what a cryptographic hash function is in your own words. Be prepared to share with the class.

Explain why a cryptographic hash function is important.

Turn to your neighbor and explain why a cryptographic hash function is important in your own words. Be prepared to share with the class.

Explain what bcrypt is.

Turn to your neighbor and explain what bcrypt is in your own words. What is salt and why is it used in hashing functions like bcrypt?

Register a user with a hashed password.

A user sends their personal information to an HTTP server, including a unique account name and an unhashed password.
On the server, bcrypt is used to generate a hashed password.
The user's personal information is inserted into the database with the hashed password replacing the unhashed password.
The server informs the client that the user registration was successful by sending it the resulting row minus the hashed password.

Using the list of steps above, implement a /users POST route to register a user.

dropdb trackify_dev
createdb trackify_dev

To start off by cloning the lesson repo, installing dependencies and opening it in atom.

git clone https://github.com/Shurlow/user-registration-lesson.git
cd user-registration-lesson
npm install
atom .

Take a minute to explore the project files before moving on.

1 - A user sends their personal information to an HTTP server

Create a new users.js route file inside the routes folder. (for now just have this route respond with a 200 status code)

Don't forget to link the route as middleware in server.js

const users = require('./routes/users');
app.use(users);

Then, start the HTTP server with nodemon.

nodemon server.js

In a new Terminal tab, then run the following shell command.

http POST localhost:8000/users

2 - bcrypt is used to generate a hashed password

Install the bcrypt package with the npm.

npm install --save bcrypt

Use the bcrypt.hash() method to generate a hashed password when the /users route is matched.

Then, run the following shell command.

http POST localhost:8000/users [email protected] password=theone

users.js Code:

'use strict';

const bcrypt = require('bcrypt');
const express = require('express');

const router = express.Router();

router.post('/users', (req, res, next) => {
  bcrypt.hash(req.body.password, 12)
    .then((hashed_password) => {
      console.log(req.body.email, hashed_password);
      res.sendStatus(200);
    })
    .catch((err) => {
      next(err);
    });
});

module.exports = router;

3 - The user's personal information is inserted into the database

Create the migration file to define the schema for the users table.

npm run knex migrate:make users

Inside the new migration file, write the following code.

'use strict';

exports.up = function(knex) {
  return knex.schema.createTable('users', (table) => {
    table.increments();
    table.string('email').unique().notNullable();
    table.specificType('hashed_password', 'char(60)').notNullable();
    table.timestamps(true, true);
  });
};

exports.down = function(knex) {
  return knex.schema.dropTable('users');
};

Migrate your database with the latest migration file.

npm run knex migrate:latest

Update the /users route to insert the new users into this table along with their hashed_password.

return knex('users').insert({
  email: req.body.email,
  hashed_password: hashed_password
}, '*');

4 - The server informs the client that the user registration was successful

If the insertion is successful, notify the client by sending it the newly created user record without the hashed password. It's critical that the hashed password never leave the server.

.then((user) => {
  delete user.hashed_password;
  res.send(user);
})