Lecture 3

Talking to Servers

Your page lives somewhere. What happens when someone types your URL?

Hour 1 — The journey of a request

  • Client-server architecture — the fundamental shape of the web
  • What happens when you press Enter: DNS (the phonebook), IP addresses (the street addresses), HTTP/HTTPS (the language)
  • Requests and responses; status codes worth knowing (200, 404, 500)
  • What the browser actually does: parse, render, paint
  • HTTPS and the padlock — what encryption does and doesn't protect

Hour 2 — Watch it happen

  • Exercise: Exercise - Trace a RequestExercise - Trace a Request
    Watch your website load, piece by piece

    Use the browser's Network tab to observe everything that happens between typing your URL and seeing your page.

    Steps


    Open your own site (from Exercis...
    — use the Network tab to watch your own site load, piece by piece
  • Reading a URL like a sentence: protocol, domain, path, query string

Homework

  • Find the slowest-loading site you regularly use. Screenshot its network waterfall and bring a theory about why it's slow.