ITCamp 2011 - Florin Cardasim - Duplex Communications with WCF and Azure

IT Camp 2011
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Duplex Communications with WCF and Azure
Florin Cardașim, software developer
RomSoft Iași, www.rms.ro
caf@rms.ro | twitter.com/cardasim

Session agenda
Enterprise duplex. Non-browser clients
WCF duplex bindings, router service
Windows Azure Service Bus
Web duplex. Browser clients
Simple polling, comet/long polling
WebSockets
Q&A

Enterprise duplex
Non-browser clients
- WCF duplex bindings, router service
- Windows Azure Service Bus

Full duplex using WCF NetTcpBinding
Event
publisher
Event
consumer
Full duplex TCP
Publisher requires public IP
Custom ports open in firewall

“Full duplex” using WCF WSDualHttpBinding
Event
publisher
Event
consumer
NAT
Duplex HTTP
Network address translation makes connection back impossible

“Full duplex” using WCF WSHttpBinding
Event
publisher
Event consumer
Dual HTTP
Publisher and consumers require public IP
That’s fine, BUT we want the servers INSIDE the enterprise

WCF Router Service
Event
publisher
Router Service
Event
consumer
Router Service
TCP
Dual HTTP
TCP
Firewall and NAT friendly
Routers have protocol bridging, failover etc
Not bad, but quite crowded.
Can you do better?

Windows Azure Service Bus
sb://itcampnamespace.servicebus.windows.net/publisher
Relay Service
Event
publisher
Event
consumer

DEMO
Connecting the enterprises via:
NetTcpBinding, WsDualHttpBinding
RouterService, NetTcpBinding, WsDualHttpBinding
Service Bus, NetEventRelayBinding

Enterprise duplex: conclusions
Direct TCP is best IF available
public endpoint , open ports in firewall
Duplex HTTP is an alternative
public IP both publisher and consumer, port 80
Router Service bridges the enterprises
flexible, but quite complicated deployment
Azure Service Bus
very flexible & powerful; requires careful planning because each connection costs money 

WEB duplex
Browser clients
- Simple polling, comet/long polling
- WebSockets

Http polling
Wasted resources, many requests return no data
Frequent polling means higher load on the server

Comet/long polling
Bandwidth: small payload, large http headers overhead
Scalability: pressure on memory, bandwidth, threads/processes

DEMO
An open source, WCF based, long polling server implementation:
http://laharsub.codeplex.com/

Html5 WebSockets
Full duplex, bidirectional
Single TCP socket
Standard ports: http/80, https/443
Bandwidth savings
More scalable than Comet
Nice programming model
In&outside of browser
Server
Open WebSocket Connection
Client
Drafts:
IETF WebSockets Protocol
-W3C WebSockets API

Html5/websockets: server
Socket.IO Fallbacks
Adobe Flash Socket
AJAX Long Polling
AJAX Multipart Streaming
Forever iFrame
JSONP Polling
http://socket.io/
Socket.IO (Java, node.js)
Jetty (Java)
Ruby/EventMachine
Python/Twisted
WCF websocket prototype 
… others

Html5/websockets: server
Test browser support: http://websocket.org/echo.html
Microsoft is still experimenting 
http://html5labs.com

DEMO
Some WebSockets in action:
http://kaazing.me
http://retrospectiveapp.heroku.com

DEMO
Using the WCF WebSockets prototype from http://html5labs.com

References
channel9.msdn.com/Learn/Courses/Azure/ServiceBus
en.wikipedia.org/wiki/Comet_%28programming%29
html5rocks.com/tutorials/websockets/basics
websocket.org
pusher.com
kaazing.com
live.visitmix.com/MIX11?q=web+sockets
paulbatum.com

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ITCamp 2011 - Florin Cardasim - Duplex Communications with WCF and Azure

by Florin Cardasim

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ITCamp 2011 - Florin Cardasim - Duplex Communications with WCF and Azure Presentation Transcript