Networking 101

Open two windows

Server:

$ make run.bash

Client:

$ make exec.bash

Stream Sockets

UNIX

Server:

$ echo PONG | nc -Uvl server.sock

Bound on server.sock
Listening on server.sock

Client:

$ echo PING | nc -Uv server.sock

PONG

TCP

Server:

$ echo PONG | nc -lvkN 3000

Listening on 0.0.0.0 3000

Client:

$ echo PING | nc -v localhost 3000

Connection to localhost (127.0.0.1) 3000 port [tcp/*] succeeded!
PONG

HTTP (over TCP)

Server:

$ echo -e 'HTTP/1.1 200\r\nContent-Type: application/text\r\n\r\nPONG' | nc -lvkN 3000

Listening on 0.0.0.0 3000

Client:

$ curl http://localhost:3000/ -d PING

PONG

Running a complete web server (simple homepage, login and logout)

Server:

$ bash http/005-login/server

Listening on 3000...

HTTP client using a web browser

Open your preferred web browser at http://localhost:3000.

HTTP client using cURL

Accessing the homepage:

$ curl http://localhost:3000/

<form method="POST" action="/login">
  <input type="text" name="name" />
  <input type="submit" value="Login" />
</form>

Performing the login:

$ curl -vi -X POST http://localhost:3000/login -d 'name=Leandro'

HTTP/1.1 301
Location: http://localhost:3000/
Set-Cookie: name=Leandro; path=/; HttpOnly

Accessing the homepage again but using the provided cookie:

$ curl -H 'Cookie: name=Leandro' http://localhost:3000/

<p>Hello, leandro</p>
<form method="POST" action="/logout">
  <input type="submit" value="Logout" />
</form>

Performing the logout using the provided cookie:

$ curl -vi -X POST -H 'Cookie: name=leandro' http://localhost:3000/logout

HTTP/1.1 301
Location: http://localhost:3000/
Set-Cookie: name=leandro; path=/; HttpOnly; Expires=Thu, 01 Jan 1970 00:00:00 GMT

HTTP client using a bash script with file descriptor

Login:

$ bash http/005-login/client

HTTP1.1 200
Content-Type: application/text

Login (type your name):
Leandro

Menu:

Leandro
HTTP/1.1 301
Location: http://localhost:3000/
Set-Cookie: name=Leandro; path=/; HttpOnly
HTTP/1.1 200
Content-Type: application/text

Hello, Leandro
Deseja fazer logout? (s/n/q):

Enjoy!