Net Remoting pdf

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.NET
Remoting
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Net Remoting Definition:
• Application which is located in another
application domain or process can
communicate with another by using .Net
Remoting.
• Net Remoting allows processes to share
the objects. It can call the method and can
access the properties of an objects that
are:
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
Hosted in different application domain
with in the same process or

Different process executing on same
computer or

Different computers connected by LAN
or

Different computer distributed over world
wide
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Modern applications are no longer stand-alone
applications.
.NET Remoting:
- Provides a solution for
communication between
application domains
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You known Application Domain ?:
Application domain is the collection of
classes, which isolate these from other
applications. The application in one
application domain could not access the
application in other application domain
(without using Remoting)
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2 Object type
• It can be accessed outside
its application domain.
Remotable
Object
Non
Remotable
Object

CLR objects cannot, by default, be
used outside their AppDomain
- No way to copy them
- No way to reference them


Exception occurs when you try to
pass an object reference to a
different domain

SO: It can not be accessed outside
its own application domain.
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Remotable Object:

Can request that instances of a class be
accessible outside original AppDomain
– Client get a copy of the object
– Client get a reference (proxy) to the
original object

When an object is Remotable?
The object should inherit the class
System.MarshalByRefObject

Two Types of Remotable Objects are there
– Marshal by Value
– Marshal by Reference
*More detail later
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Object Serialization:
Conversion of an object (instance) into a data
stream of bytes, Serialization is a method of

persisting objects for storage in a database, to
various media, or during marshaling—the
process of moving an object to a new
application domain, context, process, or
system. Serialization is performed by the
Common Language Runtime (CLR).
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MarshalByRef objects:

When the object's class derives, directly or
indirectly, from MarshalByRefObject, the
runtime creates a proxy to the object
[Serializable]
class Foo : System.MarshalByRefObject
{
. . .
}

Clients in foreign AppDomains receive
proxy

How does a client specify what proxy?
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Serializable objects:

When runtime can make a copy of the object,
an object can marshal-by-value to other
AppDomains

– Add SerializableAttribute
– Or implement the ISerializable interface
[Serializable]
Class Far {
. . .
}
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Remoting in general :

Clients must connect to servers

Server needs to publish an object
• I listen on this TCP channel and that HTTP
channel
• I have a service called "MathService"
• When client connects to MathService using
a supported channel, give the client [ a | this ]
Calculator instance

Clients need to specify the desired object
• Connect to the "MathService" on server
"LightningFast" using protocol HTTP on port 80
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ASP.NET Web services (WS)
vs
.NET Remoting (NR)
See next slide…
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1. WS: only be accessed over HTTP; NR
various protocols like TCP, HTTP etc.
2. WS stateless environment, NR state
management
3. WS more reliable than .NET Remoting.
4. WS are easy to create and use, NR are
complex to be created.
5. WS across platforms, NR requires client
to be built using .NET
6. WS support datatypes defined in the XSD
type system while .NET remoting provides
support for rich type system using binary
communication.
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.Net Remoting components

A remotable object.

A host application.
– listen to requests for the hosted
remotable object.

A client application.
– requests for the remotable object.
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How Does .NET Remoting Works?


In the client
– create a new remotable object
=>creates a proxy object
– When client call method => call method on
proxy=> server=> return to proxy => client
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Proxy

To avoid conjunction in networking. It
contains reference to all methods and
properties of object. There are two type of
proxy.
– Transparent proxy (There is no physical
existence, Created by IISserver)
– Real Proxy (Physical Existence)
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
Remoting makes an object in server
available to code in client => marshalling

2 ways to marshal an object
– Marshal by value
• the server creates a copy of the object
passes the copy to the client
– Marshal by reference
• the client creates a proxy for the object
and then uses the proxy to access the
object

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Marshal by reference

2 types
– Server-Activated Objetcs (SAO)
– Client-Activated Objects (CAO)

Client-Activated Object:
– Server side object creation is handled by client application.
– An instance of object is created, when the client calls the new
operator.

Server-Activated Object:
– The object is created, when the client actually invoke a
method on proxy.
– Single Call (stateless)
• This object handles one and only one request coming from
client.
– Singleton
• This can be used to retain the state across multiple
method calls.
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SAO - CAO

Server-Activated
• lifetime is controlled by server
• Use when there are clients sharing the same server
object

• It’s a one-to-many relationship between the server
object and clients
– Singleton – SingleCall  Is called: WellKnow object

Client-Activated Objects
• lifetime is controlled by the client
• Use when multiple server instances of the same kind
need to be run on the server at the same time
• one-to-one relationship between each server object
and its corresponding client
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Client-activated objects
Client-activated objects. Each
client gets an independent
object for its use. Like the
classic client-server model,
clients can still share objects.
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Server-activated objects:
Singlecall
Singleton
Obj 3
Obj 1
Obj 2
Obj 4
Obj
n
Obj

A
Share
Share
Share
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Terms using in .Net Remoting

Channel

Formatters
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
Channel:

The medium through the which the
messages would be transferred

The remote objects are to communicate
with one another and channels do this
transport job of communication.

The two existing channels
– HttpChannel and TCPChannel
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
HTTPChannel
– use SOAP Formatter to serialize

messages into the XML format using SOAP
protocol. Using SOAP method allows the
client to call method on the remote object
that might not be using .Net framework.

TCPChannel
– use binaryFormatter to serialize message
into binary stream.

Channel:
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
Channel:

We have to register at least one channel to use with
the remoting infrastructure before being able to call
the Remotable type from the client application.

We can register a channel in one of two ways:
– By “ChannelServices.RegisterChannel”, or
– By using a configuration file.

We have to choose a specific port for your channel
to listen on.

If we are not sure whether a port is available or not,
use 0 (zero)

When you configuring your channel’s port and the

remoting system will choose an available port for
you.