Communication protocol that provides consistent connection between client and server.

• introduced in 2011

Django HTTP

• django uses WSGI server to communicate with its browser
• WSGI server is synchronous

WebSocket

• asynchronous connection
• requests can be handled independently from each other, simultaneously
• need to use a ASGI server for this application
• ASGI server is a more modern versino of WSGI server that can handle both sync and async

Websocket flow

• Browser sends upgrade request to websocket → server responses with WS handshake
• WS handshake involves an exchange of security keys with hashing
• ASGI server does not come automatically with django and has to be installed manually
  • in this case we use daphne
  • there are alternatives like uvicorn or hyper corn

flow

browser → requests standard html → server responds → client request with htmx requesting for upgrade → server initiate websocket handshake

django channel

• django channel is unique for each individual user
  • one to one relationship
• In order to broadcast message to many users we have to upgrade again we have to add a channel layer
  • Channel layer can add individual channel to a group
  • we need inmemory data store which manages the communication between all the different parts
  • for development we can use inbuilt data store django channel provides
  • for production better to use redis