.NET Remoting

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.NET Remoting

• Adventures Among the App Domains

Dean Fiala
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Overview

• What is Remoting?
• How is it different from Web Services DCOM?
• What are the Use Cases for Remoting?
• How does Remoting work?
• What does a Remoting Application look like?

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What Is Remoting?

• Remoting allows a client application to reference
  and use objects
• In another AppDomain
• In another process
• On a remote machine
• In short, it is the basis for a distributed
  architecture

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Distributed Architecture Use Cases

• Physical Tier Separation
• Centralize Business Logic
• Load Balancing
• Disconnected Use

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DCOM vs Remoting
Remoting
DCOM

• Requires TCP
• Object Lifetime requires pinging and reference
  counting
• Configuration Registry Fun

• TCP HTTP channels
• Leases and sponsors manage object Lifetime
• Configuration uses .config files

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Web Services vs Remoting
Remoting
Web Services

• HTTP only
• Text Formatting
• IIS Host
• Leverages IIS Authentication/Encryption
• WSDL

• TCP HTTP channels
• Text or Binary Formatting
• IIS or Custom Host (Windows Service, WinForm,
  Console)
• More Complex Object support

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Remoting Use Cases
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Marshalling Choices

• Marshall By Value Server object is serialized,
  returned to the client and runs within the client
  process. Class must use Serializable attribute.
• Marshall By Reference Server object is
  instantiated and run in the server process and is
  referenced by the client. Class must inherit
  MarshalByRefObject.

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Activation Choices

• Server Activated Object (SAO) Singleton all
  clients access the same object
• SAO Single Call object is created, used for
  one method call and then disposed
• Client Activated Object (CAO) Explicitly
  created by the client on the server, maintains
  state between method calls

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Remoting Architecture Choices

• Shared Assembly Server objects exist in an
  assembly on both client and server, runtime
  determination is made which to invoke good for
  occasionally disconnected apps
• Shared Interface Client and server refer to the
  same Interface assembly, but only server objects
  implement the methods
• Generated MetaData Extract metadata
  (interfaces, objects, etc.) from the Server
  assembly and build client assembly

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How Does Remoting Work?
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Local Proxy Object

• Has same method signatures as the Server Object
• Is created transparently when a call to a
  Server Object method is made
• Creates a Channel object to route the request
  to the server

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Formatter Sink

• First Sink in the Client Channel objects sink
  chain
• Serializes the method call to the Server Object
  into the appropriate format for the Channel
• Two standard Formatters are Binary and SOAP

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Transport Sink

• Last sink in the Client Channel object chain
• Transports the method call to the destination
  port on the Server

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Transport Sink - Server

• First sink in the Server Channel object chain
• Receives the request from the client

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Formatter Sink - Server

• Last Sink in the Server Channel objects sink
  chain
• Deserializes the method call into its original
  format

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Dispatcher

• Locates the proper assembly in the server
  application
• Instantiates the object
• Invokes the method

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Remoting Server

• The following can all act as Remoting Servers..
• IIS
• Windows Service
• WinForms App
• Console Application

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Remoting Client

• WinForm App
• Web App
• Web Service
• Console App
• Windows Service

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Sample Application

• Demonstrate
• WinForms Client
• Web Client
• Remote Server (Windows Service)
• Interface Assembly

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More Information

• IngoRammer.com http//www.ingorammer.com/Remotin
  gFAQ/
• Develop Distributed Applications using Microsoft
  .NET Remoting (Online Seminar)http//www.microsof
  t.com/seminar/shared/asp/view.asp?url/Seminar/en/
  20020531devt1-54/manifest.xml
• Design and Develop Seamless Distributed
  Applications for the Common Language Runtime
  http//msdn.microsoft.com/library/default.asp?url
  /msdnmag/issues/02/10/netremoting/toc.asp
• ASP.NET Web Services or .NET Remoting How to
  Choose http//msdn.microsoft.com/library/default.a
  sp?url/library/en-us/dnbda/html/bdadotnetarch16.a
  sp
• Advanced .NET Remoting (Book)http//www.amazon.c
  om/exec/obidos/tg/detail/-/1590590252/qid10830813
  59/sr8-1/refpd_ka_1/102-6505139-8209727?vglance
  sbooksn507846

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Very Practical Software, Inc.

• Rockville, Maryland
• http//www.vpsw.com