As a technical interviewer, one of the questions I like to ask the most is "what happens when I write www.example.com in the browser and then press enter?". The answer reveals a lot about the interviewee's understanding of a vast number of technologies that fringes web development. In this talk, I go through exactly what happens, down to excruciating detail, so that you will be better prepared for your future job interview.

1. Tobias Sjösten

2. What happens
when I press enter?

3. A Sf

4. https://tobias:secret@www.stim.se:79/hej?q=a#x
protocol credentials domain port path query
frag
ment

5. TCP/IP

6. DNS

7. TCP/IP

9. HTTPS

11. GET /hej HTTP/1.1
Host: www.stim.se

14. 0 1 2 3 4 5 6 7 8 9
0 1 2 3 4 5 6 7 8 9 A B C D E F
0 1

15. 0
1
2
3
4
5
0
1
10
11
100
101

16. G = 71 = 01000111
E = 69 = 01000101
T = 84 = 01010100

18. A

19. A

21. interface HttpKernelInterface
{
public function handle(Request $request): Response;
}

22. $request = Request::createFromGlobals();

23. kernel.request

24. class RouterListener implements EventSubscriberInterface
{
public function onKernelRequest(Request $request)
{
$request->set('_controller', …);
}
}

25. class ControllerResolver
{
public function getController(Request $request)
{
return $request->get('_controller');
}
}

26. kernel.controller

27. class MyController
{
public function hej()
{
return new Response(’hej!');
}
}

28. kernel.response

29. $response->send();

30. HTTP/1.1 200 OK
Content-Type: text/html
Content-Length: 4
hej!

31. A

34. FIN

35. @tobiassjosten