Using Twisted with Everything Else

by LVH

Why should you care about Twisted?

Async before it was cool!
IRC, SMTP, DNS, SSH, Websockets
Time events, sane process and thread management
Protocol and transport abstractions
Twisted vs Django, Flask, et al
- Incoming e.g. a chat server
- Outgoing e.g. a scraper

Prereqs for this talk

Python
Possibly Twisted

How Twisted Works

Reactor
- Object
  - Register new events
  - Waits for events
  - Dispatches them when they occur
- Internally an event loop
  - Except for test reactors e.g. clock
  - backed by some event mechanism
Reactor Interfaces (usually call higher-level APIs)
- IReactorBase: run, stop
- IReactor(TCPSSLUNIX|etc)
Deferreds
- An object that you get now
- Gets you a result (or failure!) later
- Very flexible
- Used because operations take time now and you can't always get a response right now
- Blocking API
  - Evaluate or raise some point in the future
  - Thread can't do anything else in the meantime
- Deferrred API
  - Get an object representing the future result right now

SOA - Service Oriented Architecture

Loosely coupled things that talk to each other
Components written in Python, Cobol,