Using slanger and websockets to power a warehouse backend

Transcript

1. $whoami Samstag, 18. August 2012

2. Using slanger and websockets to power a warehouse backend Samstag,

   18. August 2012

3. © NBC Samstag, 18. August 2012

4. What? •a web application for a printing company to simplify

   the packing process Samstag, 18. August 2012

5. What? •the system runs on a touchscreen desktop in kiosk

   mode and needs to be synchronized in realtime Samstag, 18. August 2012

6. © NBC Samstag, 18. August 2012

7. websockets •native browser support •real bi-directional connection •less overhead than

   ajax-requests •easier to handle than long-polling Samstag, 18. August 2012

8. © NBC Samstag, 18. August 2012

9. protocol •roll your own •pre-made Samstag, 18. August 2012

10. pusher •a webservice sending realtime messages between clients •german Datenschutz:

    can not send german client data to an us-based service Samstag, 18. August 2012

11. © NBC Samstag, 18. August 2012

12. slanger •open source websocket server •runs on a local machine

    •compatible with pusher‘s API •thus compatible with pusher. js Samstag, 18. August 2012

13. architecture •Padrino backend •slanger •html-5 client Samstag, 18. August 2012

14. architecture •application handles entity changes and sends events to slanger

    •client subscribes to slanger events •slanger dispatches events to the client •client uses event data to render mustache templates Samstag, 18. August 2012

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17. advantages •very simple client side js code •almost no logic

    in the client •server side business logic Samstag, 18. August 2012

18. © NBC Samstag, 18. August 2012

19. handle with care •Never mix client-side events with server-side events

    •keep all business logic on the server •Minimize assumptions about event behaviour in the client Samstag, 18. August 2012

20. © NBC Samstag, 18. August 2012

21. © NBC Samstag, 18. August 2012

22. pitfalls •correct redis version (≥2.4.14) •slanger is an app, not

    a lib Samstag, 18. August 2012

23. stuff • https://github.com/stevegraham/slanger • https://github.com/defunkt/resque • http://redis.io/ • https://github.com/padrino/padrino-framework •

    http://handlebarsjs.com/ • http://twitter.github.com/bootstrap/ • http://www.websocket.org/quantum.html Samstag, 18. August 2012

24. © NBC Samstag, 18. August 2012