Real-time Communications with SignalR

Transcript

1. Real-time Communications with SignalR Shravan Kumar Kasagoni
2. Agenda 1) Introduction to the real-time web 2) ASP .NET SignalR 3) Building a real-time
3. Real-time Application? Real-time functionality is the ability to have server code push content to connected clients instantly as it becomes available, rather than having the server wait for a client to request new data.
4. Without real-time
5. With real-time
6. Why Real-time? Users want the latest info, NOW!
7. Show Me Some Examples  Twitter, Facebook, Mail - live searches/updates  Stock streamers  Auctions  Interactive games  Live Scores  Collaborative apps (google docs, office web apps)  Live user analytics (live graphs)
8. How to build real-time web apps?
9. HTTP is an old beast… Never designed for real-time communications  Web is all about request-response  Web is stateless
10. How to do real-time in web?
11. Periodic polling  Poll from time to time using Ajax  Delay in communication due to polling interval  Wastes bandwidth & latency Server Client Polling interval
12. Long polling  Poll but doesn’t respond until there's data  Poll again after data received or after the connection times out  Consumes server & threads & connection resources Server Client
13. Forever Frame  Server tells client that response is chucked  Client keeps connection open until server closes it  Server pushed data to the client followed by \0  Consumes server threads Server Client
14. HTML5 Web sockets  Extension to HTTP  Provides raw sockets over HTTP  Full-duplex  Traverses proxies  It's still a working draft  Not every proxy server supports it  Not every web server supports it  Not every browser supports it  They are raw sockets!
15. too many options
17. Basically…
18. Introducing SignalR • Abstraction over transports • Events instead of task/async • Connection management • Broadcast or target specific client
19. What does SignalR do? • Client to Server persistent connection over HTTP • Easily build multi-user, real-time web applications • Auto-negotiates transport
20. SignalR Fallback Long Polling Forever Frames Server Sent Events Web Sockets
21. What does SignalR do? • Allows server-to-client push and RPC • Built async to scale to 1000’s of connections • Scale out with Service Bus, SQL Server & Redis • Open Source on GitHub
22. Backplane SignalR Backplanes Load balancing via a common transport mechanism
23. Thank You