Resources for WebSockets with Python
Before you learn node.js to handle WebSockets or any type of full-duplex client-server communication, check out some Python options first. In this post I'll lay out some of the resources that I found most helpful for getting started coding Python web applications that use WebSockets.
It's not necessary to have seen either talk but this page goes along with the San Francisco Python January 2015 meetup and Django District March 2015 meetup events.
Before diving in make sure you check out the WebSockets page on Full Stack Python. The page is new so it's a bit sparse at the moment but I'll continue filling it out throughout the rest of the month.
One more shamless plug: if you're going to PyCon this year make sure to check out the talks virtualenv for new Pythonista on Friday and Choose Your Own WSGI Deployment Adventure on Saturday.
Code for the WebSockets Talk
All code for the meetup live demo can be found on GitHub in the python-websockets-example repo.
The slides are also available but do not make a lot of sense without corresponding audio of the presentation.
General WebSocket resources
The below WebSocket resources aren't specific to Python but it's a good idea to get grounded in the technology itself first.
- There is an official RFC for WebSockets that is a good place to start if you prefer to go straight to the source. I generally read a few summaries by other folks before diving into an RFC.
- WebSockets 101 provides context for what's good and not so good about the WebSockets protocol.
- Can I Use? has a nice chart for what browsers and versions support WebSockets.
- Mozilla's WebSockets documentation is good for a range of explanations and tutorials.
- This chapter from High Performance Browsering Networking is a comprehensive overview of WebSockets.
Evented networking frameworks
I recommend reading the awesome-python list of concurrency and networking libraries.
In the SF Python January 2015 and Django District March 2015 meetup groups I used gevent with Flask, Flask-SocketIO and SocketIO to handle WebSocket connections.
WebSockets with Python web frameworks
These resources are specific to using WebSockets with Python web frameworks like Django, Flask and Bottle and Klein. Each tutorial will show you step-by-step how to implement WebSockets with that framework.
- I highly recommend Miguel Grinberg's blog post on WebSockets with Flask.
- My Choose Your Own Adventure Presentations blog post shows how to use Flask, gevent, Reveal.js and SMS to create interactive presentations.
- Going asynchronous: from Flask to Twisted Klein explains how to use Klein for async apps as a replacement for Flask.
- Real-time Web Apps with Django and WebSockets is a few years old but still relevant for implementing WebSockets if you're using Django.
- Async with Bottle is a walkthrough for the Bottle framework.
WebSockets vs WebRTC Data vs SSE
There are multiple ways to accomplish server push and full duplex communication between web browsers and a server. The WebRTC Data Channel and Server-Sent Events (SSE) can provide similar functionality to WebSockets, although there are differences such as SSE not being able to push from client to server, only server to client. There is often confusion for how these technologies compare so it's a good idea to read a few of the posts below to survey the landscape.
- This post on WebRTC Data Channels vs WebSockets specifically addresses where data channels are currently appropriate and where they are less useful.
- There's a well done Stack Overflow discussion on WebSockets vs SSE.
- These slides roll through what WebSockets, SSE and WebRTC are.