Implementing real time web applications with Django
19 likes10,282 views
Kristian Øllegaard presented an approach for implementing real-time web applications using Django. He discussed using Node.js with Socket.io for the real-time capabilities and Redis for cross-language communication between the Node.js and Django applications. He demonstrated publishing messages from Django to a Redis queue that the Node.js application subscribed to and then emitted to the browser via Socket.io, providing real-time updates. While the approach can be used today, he cautioned against doing so without further work on aspects like client authentication.
Ad
More Related Content
What's hot (20)
Similar to Implementing real time web applications with Django (20)
Ad
Recently uploaded (20)
Ad
Implementing real time web applications with Django
- 1. Implementing real time web applications with Django Kristian Øllegaard 1 onsdag den 6. juni 12
- 2. About me • Software Developer/System Administrator at Divio • Django since 0.96 • Danish, lived in Zurich 1,5 year @oellegaard github.com/KristianOellegaard 2 onsdag den 6. juni 12
- 3. Why real time? • Better user experience • More options in front end • Make the web feel like native apps • Showing live data. • Collaboration is much easier. @oellegaard github.com/KristianOellegaard 3 onsdag den 6. juni 12
- 4. Finding the right tool • Criteria's • Use websockets, but have fallbacks • Good browser support (incl. old IE) • Should be usable from python • Does not require extensive changes in frontend • “As fast as it can be” @oellegaard github.com/KristianOellegaard 4 onsdag den 6. juni 12
- 5. The tools you want Node.js + Socket.io @oellegaard github.com/KristianOellegaard 5 onsdag den 6. juni 12
- 6. The tools you want Node.js + Socket.io (well, we don’t want this, but socket.io needs it) @oellegaard github.com/KristianOellegaard 5 onsdag den 6. juni 12
- 7. The tools you want • Node.js • Built on Chrome's JavaScript runtime • Uses an event-driven, non-blocking I/O model • Socket.io • One interface for all transport methods (sockets, polling, etc.) • Compatible with almost everything @oellegaard github.com/KristianOellegaard 6 onsdag den 6. juni 12
- 8. Why not implement it in Python? • Already active community • Can be used from python without too much trouble • Most people know very basic javascript • More importantly, frontend engineers, knows javascript and can therefore contribute to the different browser-specific implementations. @oellegaard github.com/KristianOellegaard 7 onsdag den 6. juni 12
- 9. Using redis for cross-language communication • Support for many datatypes • Can be used both as storage and as a queue • Implemented in many different languages • For the usage in this talk, any other queue could have been used as well. @oellegaard github.com/KristianOellegaard 8 onsdag den 6. juni 12
- 10. Basic concept • Something happens, the user Redis must be notified in real time publish publish • subscribe From e.g. django we insert the E.g. new value into the queue Django Node.js Celery • Node.js listens on the queue subscribe and emits any content directly Browser to the browser via socket.io • This is btw. very fast! @oellegaard github.com/KristianOellegaard 9 onsdag den 6. juni 12
- 11. Sample node.js app var io = require('socket.io').listen(8001); var redis = require('redis').createClient(); redis.psubscribe("socketio_*"); // Could be any pattern io.sockets.on('connection', function (socket) { redis.on('pmessage', function(pattern, channel, key){ socket.emit(channel, key); }); }); @oellegaard github.com/KristianOellegaard 10 onsdag den 6. juni 12
- 12. Sample HTML/JS <script src="http://localhost:8001/socket.io/socket.io.js"></script> <script> var socket = io.connect('http://localhost:8001/'); socket.on('socketio_news', function (data) { console.log(data); }); </script> @oellegaard github.com/KristianOellegaard 11 onsdag den 6. juni 12
- 13. Sample usage from Python import redis import json redis_subscribe = redis.StrictRedis() redis_subscribe.publish("socketio_news", json.dumps({ 'title': 'Djangocon 2012', })) @oellegaard github.com/KristianOellegaard 12 onsdag den 6. juni 12
- 14. Short demo @oellegaard github.com/KristianOellegaard 13 onsdag den 6. juni 12
- 15. Hosting socket.io • Nginx does not support websockets! • Needs its own app, if hosted on an application cloud (e.g. heroku) • Recommended to expose the node server directly • But hey, it’s node.js, it scales! @oellegaard github.com/KristianOellegaard 14 onsdag den 6. juni 12
- 16. Can I use this today? • Yes • But, please don’t @oellegaard github.com/KristianOellegaard 15 onsdag den 6. juni 12
- 17. Client Authentication • Socket.io handles authentication from node -> client • Currently no authentication between django and node. • Could possibly be solved by storing your sessions in redis and checking them on connection. @oellegaard github.com/KristianOellegaard 16 onsdag den 6. juni 12
- 18. Notes • Concept should work with any language/framework • E.g. communicating between ruby and python @oellegaard github.com/KristianOellegaard 17 onsdag den 6. juni 12
- 19. Questions? http://kristian.io @oellegaard @oellegaard github.com/KristianOellegaard 18 onsdag den 6. juni 12