rocketseat-bootcamp2020-module01

Understanding Node.JS - Basic Concepts

What is this project about?

This is project is about practicing the basic concepts behind Node.JS that were learned during the first module of GoStack 10 - Bootcamp.

How to run this project?

Install dependencies:
- yarn
Start the back-end:
- yarn dev
It's possible to test the GET methods through the browser, but for the other methods I recommend using applications such as Insomnia or Postman.

Logbook

Day 01 - 2020/01/27

Basic Concepts of a REST API
- How does it work?
  - Resquest & Response flow:
    1. Request is made by the client (e.g.: browser)
    2. Response is returned - by the server - through a data structure (e.g.: JSON)
    3. Client gets the response and processes the result
Routes use HTTP methods
1. GET: http://myapi.com/users
  - Looks for data
2. POST: http://myapi.com/users
  - Creates data
3. PUT: http://myapi.com/users/1
  - Updates a piece data
4. DELETE: http://myapi.com/users/3
  - Deletes a piece of data

Benefits
- Multiple clients (front-end) using the same back-end
- Standard communication protocol
  - Same structure for web/mobile/public API
  - Communication with external services
Request Content
- GET: http://myapi.com/company/1/users?page=2
  - routes: /company & /users
  - route params: /1/
  - query params: ?page=2
- POST: http://myapi.com/company/1/users?page=2
  - User data to be created is sent through the body/request body (PUT/POST only)
    - More detailed/sensitive data
- Headers: Additional information that is not related to the request's content (e.g.: { "locale": "pt_BR })

Day 02 - 2020/01/28

HTTP Codes: Every response (back-end -> front-end) takes with it a HTTP code, that represents the response's status.
1. 1xx: INFORMATIONAL
2. 2xx: SUCCESS
  - 200: success
  - 201: created
3. 3xx: REDIRECTION
  - 301: moved permanently
  - 302: moved
4. 4xx: CLIENT ERROR (there is something wrong with the request)
  - 400: bad request
  - 401: unauthorized
  - 404: not found
5. 5xx: SERVER ERROR
  - 500: internal server error

Day 03 - 2020/01/29

Creating the application
- yarn init -y
package.json
- It has the important functionality, among many others, of saving the references to the project dependencies that were installed.

index.js

const express = require('express'); // exports a function

// Notice that express is a function that
// returns an object with many functionalities
console.log(express);

There are three types of parameters that can be part of a request:
1. Query params -> ?name=John
```
  const { name } = request.query
```
1. Route params -> /users/1 -> /users/:id
```
  const { id } = request.params
```
1. Body/Request body -> { "name": "John", "age": 27 }
```
  const { name, age } = request.body
```
Middlewares (Global and Local)
- They are a fundamental part of every Express application!
- It's a function that gets request and response as parameters (among others, e.g.: next) and transforms/check data.
1. Global
- It's always invoked, no matter what route is being triggered.
```
server.use((req, res) => {
  console.time('Request');
  console.log(`Method: ${req.method}; URL: ${req.url}`);
  next();
  console.timeEnd('Request');
});
```
1. Local
- It's applied directly to routes
- You can add as many middlewares as you feel necessary.
- Middlewares can change the request and response parameters.
Debugging the application
- Learned how to use breakpoints in VSCode.
- Understand variables' values and what is happening behind the scenes in the application.

Made with ♥ by Yago!