How does .Net Remoting works?
Remoting.Net allows components to
interact across application domains, processes, and machine boundaries, thus
allows applications to access remote resources in a networked environment. The
interaction of components is made possible through proxy in remoting
architecture. When a client calls the remote method, it’s the proxy that
receives the call. The proxy then encodes the message using formatter. The
messages are then sent over the channel to the server process where listening
channel receives the call and passes it to the remoting system. The requested
method is then invoked and results are returned back to the client.
.Net Remoting provides an
infrastructure where objects of different AppDomains can interact. A client
interacts with server object using .Net Remoting architecture. An object
interacts with other objects outside AppDomains using proxy since the objects
can't access directly anything outside AppDomain.
Point to be noted.
A remote object is implemented by inheriting MarshalByRefObject class.
A client has to obtain proxy activating a remote object by calling
CreateInstance, GetObject, or new.
Local objects can be passed as parameters when making remote calls. Local
objects are passed by value in a remote call.
The object passed as parameter in a remote call must be serialized.
Activation Model
You need to activate remote object before use. There are two activation modes
in .Net Remoting
Server Activation
In this mode, objects are created automatically when a client attempts to
access the object. The object doesn't get created when you use new keyword to
create instance of the server class.
Client Activation
In this mode, objects are created when you use new keyword to create instance
of the server class.
A server object is created and
deployed on the network that serves client requests. The server objects have to
be registered with the CLR before it can be accessed by client. The details
that have to be provided to the CLR are
Name of the assembly that should
be loaded to activate the object
The namespace and type name of the object
The name of the endpoint where the object can be accessed
The channels to be used by client to communicate have to be registered.
The registered channels then start listening for clients to connect.
Once a remote object has been
deployed, clients can connect and invoke methods on the server object.
In order to access remote object,
the client first activates the object by calling new, GetObject, or
CreateInstance. On activation request, a proxy is created to represent the
remote object. The client message in the serialized form is transported to the
server. The type of serialization depends on the channel. For example, when the
HTTP channel is used, all messages are serialized to XML and transported over
SOAP. On the other hand, TCP uses binary serialization.
On the server side, the requested
method is then invoked and results are packaged in a message and returned back
by to the client. If the target object is of type SingleCall, it will
automatically be garbage collected after the call completes.
