tharunShiv / RESTful-API-guide

A GitHub series to learn to build RESTful APIs using Node JS.

RESTful API tutorial

What's a RESTful API?

• When we want to just communicate data with the server and not HTML.

3 example use cases

1. Client (Mobile App)
2. Client (Code, features like maps)
3. Client (Browser w/SPA)

RESTful APIs are stateless backends

It has endpoints, with each endpoints having individual HTTP verbs. (methods)

Technique

1. AJAX request
2. Get response

The JSON data will be transfered here for request and response.

RESTful Constraints:

1. Client Server Architecture Seperation of concerns , RESTful API should not care about UI
2. Stateless No Client-Context ( eg: no sessions ) is stored on the server
3. Cacheabilty Responses must define themselves are cacheable or non-cacheable
4. Layered System Intermediate Servers maybe used without the client knowing about it
5. Uniform Interface
   • Resources are identified in requests, transferred data is decoupled from db schema.
   • Self descriptive messages, links to further resources returned from server are essential
6. Code on Demand (Optional) Executable code could be transferred.

First plan

1. Plan the endpoints, with the methods.
2. Mark the protected routes

install dependencies

server.js - creating the server

app.js - spinning up the express application

add the routes

Some packages:

nodemon, morgan - logging package, body-parser

Handling request body, handle CORS

What are CORS? Cross - origin resource sharing

If the client and server are on the same server, like say localhost:3000 Then it will succeed. But for a restful API, the client and server has different origins, so the request will fail. So for restful Api, we want to allow access.

So we have to disable this mechanism , by sending some headers to the server from the client

Maintain a documentation, and clearly state about the data and data format. That is the request and response data

setup the database

fill in the logic to the routes

Add validation

Linking the models if necessary and using .populate()

Image Uploading - using multer

Authentication

How is works?

Client ----------------- Server

Client sends auth data (email, pwd) to server for registration or login

Then in a normal node app we return a session, but we dont use sessions in restapi servers, and even mobile appps cannot use sessions, we will actually return a Token. This token can be stored by our clients, and the client uses this token for future requests, we verify the token and serve the request

This token is a JWT : JSON WEB TOKEN Its a JSON Data + Signature = JWT

This signature can be verified

We will use a private+public key combination. JSON data is not encryptied

steps:

1. start by creating a user model
2. implement signup, use bcrypt
3. implement login
4. use jsonwebtoken npm package for JWT
5. return JWT token on login

Protect routes using JWT

using middlewares that checks for a valid token and continue only if the token is valid

Send the token in header with

Key --------------------- Value

Authorization ------------ Bearer [jwt]

Transfer the logic to Controllers