.NET Remoting

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.NET Remoting

• Priyanka Bharatula

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Introduction

• .NET Remoting allows an application to make an
  object available across remoting boundaries,
  which includes different appdomains, processes or
  even different computers connected by a network.
• The framework provides a number of services,
  including object activation and object lifetime
  support, as well as communication channels which
  are responsible for transporting messages to and
  from remote applications.

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.NET Remoting Components

• A remotable object Which is an object that
  contain some properties and methods located in
  one application domain and you need to call its
  methods or properties from another application
  domain or process.
• A host application This is the host of the
  remotable object also called as the server
  application. The main task of this host is to
  listen to requests for the hosted remotable
  object.
• A client application This is the application
  which makes requests for the remotable object.

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Types of Remotable Objects

• There are 3 types of remotable objects that you
  can configure and choose from depending on the
  requirements of your application.
• Single Call Service one and only one request
  coming in
• Singleton Call Service multiple clients and is
  useful when data needs to be shared explicilty
  between several clients.
• Client Activation Richer than singleton in many
  aspects as they can store the state information
  between method calls for its specific client.

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.Net Remoting Basics

• Different Ways of defining interfaces
• Shared Assembly
• Shared Interface or Base Objects
• Generated Metadata Assembly (SoapSuds)
• Serialization of Data
• Encoding/Decoding of Objects natively supported
• Just need to mark such objects with
  Serializable attribute or implement the
  interface ISerializable
• Lifetime Management
• Open network connection between client-server
• Combined reference counting and pinging
  mechanisms
• Objects get lifetime when created (reset
  time-to-live)
• Sponsor registered with a server-side object
• Multiserver/Multiclient
• .Net automatically keeps track of remote objects
  origin

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Remotable Types

• Marshal-by-value
• - all serializable types.
• - can be used as parameters of remote calls
  where copy of the object is passed to the remote
  application.
• Marshal-by-object
• - Types derived from System.MarshalByRefObject
  
• - A proxy is passed to the remote application
  where methods are executed remotely

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Managing Life Time of an Object

• Lease-based object lifetime
• Each server-object associated with a lease on
  creation
• Lease has time-to-live counter, decremented in
  certain intervals
• In addition, a defined amount of time is added on
  every method call a client places on remote
  object
• Upon reaching zero time, framework looks for a
  sponsor registered with the lease.

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Managing Life Time of an Object ...

• sponsor is an object running on sever itself,
  client or any machine reachable via a network
• An object subject to garbage collection if
• A sponsor decides lease will not be renewed
• Framework unable to contact any registered
  sponsors
• If a client references time out object, an
  exception is thrown
• System.Runtime.Remoting.Lifetime class

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Channels

• Channels are responsible for passing messages
  across remoting boundaries.
• Channels must be registered before objects are
  created as per application domain.
• Two pre-defined .NET Remoting channels existing
  are the TcpChannel and the HttpChannel.

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Remoting Architecture
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Activation

• Server activated objects(SAO)
• - constructed implicitly by the server when a
  method is invoked for the first time
• - can be either singleton/single call
• Client activated objects(CAO)
• - constructed explicitly by the client using
  new or Activator.CreateInstance with an arbitrary
  constructor.
• - stateful objects

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Types of Invocation

• Synchronous Calls
• Client waits until server finishes processing the
  request
• Asynchronous Calls
• Delegates at work
• One-Way Calls
• Framework does not guarantee their execution
• Method cannot have return values or out
  parameters
• No exception thrown even if server is down or the
  method call is malformed
• Used in uncritical logging or tracing facilities

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.Net Remoting Vs Web Services

• XML Web Services
• simple, loosely coupled programming model.
• can be accessed only over HTTP and work in a
  stateless environment.
• services hosted in IIS.
• .Net Remoting
• Tightly coupled and more complex programming
  model.
• can be accessed over any protocol and support
  both stateful and stateless environments.
• services hosted in any AppDomain.

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References

• Advanced .Net Remoting Ingo Rammer Mario
• http//www.thinktecture.com/
• .Net Remoting Technical Overview
• http//msdn.microsoft.com/en-us/library/kwdt6w2k(V
  S.71).aspx
• .NET Remoting Versus Web Services
• http//www.developer.com/net/net/article.php/11087
  _2201701_1

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Thank you