.Net Remoting

Common distributed protocols are:RPC : Remote Procedure CallsDCOM : MS Distributed Object ModelCORBA : Common Object Request Broker ArchitectureRMI : Java Remote Invocation

Client

Remote Service

Client Requests remote process

Server runs the Service/process and returns the result

Not Secure for external networks

Remote Service

Distributed Application

Remote Service

Distributed systems are generally more scalable , more robust and increase availability of services

Application Domain

(Assembly)

Remote Objects

Remote Objects

Remote Objects

LocalObjects

.Net Remoting allows access to objects placed around a network.It has:•Communication channel•A formatter : This can be Binary encoded or XML encoded (SOAP)

Serialization

Communication Channel

Distributed Application

Application Domain

(Assembly) Remote Objects

LocalObjects

Communication Channel

Communication Channel

Formatter: BinaryFast but not as

compatible as XML

Formatter: XML (SOAP)

Highly compatible but not as fast

Remote Objects

Application Domain

(Assembly)

Remote Object

Typically dll

Remoting Overview

LocalObject

Invoke

Pass object/value

Get Result

Different Assemblies are used between Local and

remote Service

Application Domain

(Assembly)

Remote Service

Does the object persists?

Remote object lifetime

LocalService

Invoke

Pass object/value

Get Result

Application

Within Local Assembly

Local Objects

LocalObject

LocalObject

Pass By Value

Pass By Reference

Application Domain

(Assembly)

Public void myObject (myObjectClass obj){}

Public void myObject (ref myObjectClass obj){}

Formatter(Encoder)

Application Domain

(Assembly)

Remote Object

Remote Object System

LocalObject

Serialize

Encapsulate(SOAP)

Communicate

Desterilize

Decapsulate(SOAP)

Communicate

Application Remote Object

Remote Object Activation

Server Activated ObjectSingleton :All clients get the same instance of the server object. It can communicate with multiple clients . Life time is determined by lease based lifetime (Used for chats, community networks)Single Call :Is a type of object activation when object is discarded immediately after use. It is stateless.

Client activated objects These have a finite lease time , Once their lease time expires they are left for garbage collector. Each caller would get their copy of the object

Namespace used for remoting:System.Net :This include classes related to the networking elements of the distributed systemSystem.Runtime.Remoting : This includes classes for the remote aspects of the .NET framework , such as mechanism for remote communication between objectsSystem.Web.Services :This includes protocols relating to Web services such as those to HTTP and SOAP encapsulation

Remote Object

Marshaling

Local Object

Client object

Proxy

Remoting System Remoting System

Server Object

Client application domain Server application domain

Communication Channel

Serialization

Objects passed by reference or value for local objects . For remote it is not possible to pass by reference – Remote objects must be marshaled

Remote Object

Marshaling

Local Object

Client object

Proxy

Remoting System Remoting System

ShowCapital()

Client application domain Server application domain

Communication Channel

Serialization

Creates dll on server

aCountry

aCountry capital

capital

Remote Objectpublic class ShowCapital : MarshalByRefObject{ public ShowCapital() { } public string show ( string country) { } }

Remote Object

Object.dll

Marshaling

Local Object

Client object

Proxy

Remoting System Remoting System

ShowCapital()

Client application domain Server application domain

Communication Channel

Serialisation

Access public methods of

remotable obj

aCountry

aountry capital

capital

Remote Object

Object.dll

Marshaling

Local Object

Client object

Proxy

Remoting System Remoting System

ShowCapital()

Client application domain Server application domain

Communication Channel

Serialisation

We need object invocation.And channel configuration.Eg. TCP channel 1234 , firewalls should allow channel

Channels

• TCP Channel – Faster and more secure communication. Intended predominantly for intra-domain communication. Requires port activation for communication with external world

• HTTP Channel performed using HTTP/SOAP protocol. Good for external communication since it is implemented over HTTP/HTTPS and most firewalls allow HTTP calls through.

TCP Channel

Local Object

Client object

Proxy

Remoting System

Client application domain

Communication Channel

Server activation object

Channel=1234

Using System.Runtime.Remoting.Channel.HttpUsing System.Runtime.Remoting.Channel.Tcp

TcpChannel channel = new TcpChannel(1234)

ChannelServices.RegisterChannel(channel)

Makes sure channel is not used by other apps

Remote Object

Object.dll

Activation

Client object

Proxy

Remoting System Remoting System

ShowCapital()

Client application domain Server application domain

Communication Channel

Serialisation

Channels map onto TCP ports..Standard ports are:21-FTP23-TELNET56-DNS80-www110-POP 3>1024 : developer use

Activation

Client object

Proxy

Remoting System

Client application domain

Server Activation is typically used when objects do not required to maintain their state between method calls(Single Call ) or where there are multiple clients who call methods on the same object instance where the object maintains its state between function calls (singleton)

In a client activated object the client initiates the object and manages it for its lifetime.

Activation

Client object

Proxy

Remoting System

Client application domain

What’s the capital of Canada

Ottawa

SAO – Single call

Login Name: John

OKSend email to Bert

Ok

SAO – Singleton

Get data

Get data

Delete

CAO- Client Manages Lifetime

Registering Remote Object

• Client must have some understanding of the interface of the remote object.

• So the compiler has check accesses to remote object

ActivationRegistering remote object

Client object

Proxy

Remoting System

Client application domain

Object mode : this defines the server activation, such as SingleCall or SingletonWellKnownObjectMode.SingleCall

newClass.ShowCapitl

ShowCapital1

Remote Object

Object URI: This is the indicator that the clients use to locate the objectnewClass.ShowCapital

Assembly name: This defines the assembly in which the class is contained in.“ShowCapital1”

Type name : This defines the data type of the remote object.Typeof(newclass.ShowCapital)

Assembly

MethodClass

Activation

Client object

Proxy

Remoting System

Client application domainObject mode : this defines the server activation, such as SingleCall or SingletonWellKnownObjectMode.SingleCall

newClass.ShowCapital

Assembly : ShowCapital1

Remote Object

Object URI: This is the indicator that the clients use to locate the objectnewClass.ShowCapital

Assembly name: This defines the assembly in which the class is contained in.“ShowCapital1”

Type name : This defines that data type of the remote object.Typeof(newclass.ShowCapital)

Remote objects are registered using the RegisterWellKnownServiceType Parameters are (data type , assembly name , activation method) .eg:

RemotingConfiguration.RegisterWellKnownServiceType (typeof(newClass.ShowCapital),”ShowCapital1”, WellKnownObjectMode.SingleTon

Activation

Client object

Proxy

Remoting System

Client application domain

Remote Object

RemotingConfiguration.Configure(“myconfig.config”);

The remote object will not instantiate itself, the client is required to initialize it, or call a method. This is achieved by a client which knows the URI of the remote object and by registering the channel it prefers using GetObject :

TcpClientChannel channel = new TcpClientChannel();

ChannelServices.RegisterChannel(channel);ShowCapital sh=(ShowCapital)Activator.GetObject (typeof(newClass.ShowCapital), ”tcp://localhost:1234/ShowCapital”);

Client side

Client requires type information about the class when this client code is compiled.

1- With a reference to the assembly where the class is stored (use local dll).2- Using SOAPSUDS tool to extract metadata directly from the endpoint. SOAPSUDS connects to the endpoint and extracts the metadata, and generates an assembly or source code that is then used in the client compilation.3-By splitting the remote object into an implementation and interface class and then use the interface as a reference when compiling the client

Determining data type