Skip to content

Instantly share code, notes, and snippets.

@chemdemo

chemdemo/request_flow.md

Created June 30, 2014 04:46
Show Gist options
  • Star 1 You must be signed in to star a gist
  • Fork 1 You must be signed in to fork a gist
  • Save chemdemo/624e38e210d057044461 to your computer and use it in GitHub Desktop.
Save chemdemo/624e38e210d057044461 to your computer and use it in GitHub Desktop.
Download ZIP
what happens when you type in a URL in browser
Raw
request_flow.md
  1. browser checks cache; if requested object is in cache and is fresh, skip to #9
  2. browser asks OS for server's IP address
  3. OS makes a DNS lookup and replies the IP address to the browser
  4. browser opens a TCP connection to server (this step is much more complex with HTTPS)
  5. browser sends the HTTP request through TCP connection
  6. browser receives HTTP response and may close the TCP connection, or reuse it for another request
  7. browser checks if the response is a redirect (3xx result status codes), authorization request (401), error (4xx and 5xx), etc.; these are handled differently from normal responses (2xx)
  8. if cacheable, response is stored in cache
  9. browser decodes response (e.g. if it's gzipped)
  10. browser determines what to do with response (e.g. is it a HTML page, is it an image, is it a sound clip?)
  11. browser renders response, or offers a download dialog for unrecognized types

what happens when you type in a URL in browser

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment