1. Developing Real-Time
and Asynchronous
Web Applications
Jess Chadwick
Architect / RIA Specialist
weblogs.asp.net/jesschadwick
jesschadwick@gmail.com

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3. The Real-Time Web
• Information as it
happens
• Always Connected

4. Why Should I Care?
• User Interaction, aka “Social Networking”
• News

7. The Web Isn’t Real-Time!

8. Real-Time Web
1,000’s of users
connected at once

9. The Traditional Web
One user at a time

12. Polling
Benefits Drawbacks
• Takes advantage of how the • Wasteful – requests occur
web really works regardless of data
• Reliable • Drains server and network
resources
• Universal browser support • Doesn’t scale

14. Long Polling
Benefits Drawbacks
• Uses “standard web • Less reliable – frequent
techniques” broken connections
• Less wasteful – fewer requests • Based on request-response
than “regular” polling interaction (might be some
delay between requests)
• Universal browser support

16. Server-Sent Events
Benefits Drawbacks
• True real-time • Less reliable
(broken connections)
• Rich JavaScript API • One-way communication
(client  server)
• Universal browser support…
except

18. WebSockets
Benefits Drawbacks
• True real-time • Emerging standard
• True bi-directional • Doesn’t use “standard web
communication techniques”
• Rich JavaScript API • Less reliable
(broken connections)
• Good browser support…
except and Opera