Net Remoting Jim Fawcett CSE 791 Distributed Objects

. Net Remoting Jim Fawcett CSE 791 – Distributed Objects Spring 2002 . Net Remoting

Distributed Computing under. Net · In. Net, there are three levels of access to distributed computing machinery: – Low Level: • System. Net. Sockets – Intermediate Level • System. Runtime. Interop. Serives – Access COM objects and Win 32 API • System. Runtime. Remoting – Access channels and CLR activation – Channels based on TCP or HTTP over TCP – High Level • System. Web. Services • System. Web. UI . Net Remoting 2

Distributed Computing under. Net · System. Net. Sockets – Provides low-level access to socket objects – You create listeners and send and receive just like we did in CSE 691 – Software Modeling and Analysis · System. Runtime. Remoting – Provides access at a medium level of abstraction. – You create channels and proxies and do RPCs on remote objects – Data marshaling is much richer than under COM. You can send anything the CLR understands as long as it has a [serializable] attribute or derives from Marshal. By. Ref. • Basically you just add those. Net identifiers and the CLR takes care of everything else. . Net Remoting 3

Remoting. Net Libraries · System. Runtime. Remoting. Activation · System. Runtime. Remoting. Channels. HTTP · System. Runtime. Remoting. Channels. TCP · System. Runtime. Remoting. Contexts · System. Runtime. Remoting. Messaging · System. Runtime. Remoting. Metadata · System. Runtime. Remoting. Proxies System. Runtime. Remoting. Services · – Activate remote objects – Sets up channel sinks and sources for remote objects – Uses SOAP protocol to communicate with remote objects – Uses binary transmission over sockets – Set threading and security contexts for remoting – Classes to handle message passing through message sinks – Customize HTTP Soap. Action type output and XML Namespace URL . Net Remoting 4

Distributed Computing under. Net · System. Web. Services – Servers are hosted under IIS – Use HTTP-GET and HTTP-POST or higher level SOAP · Simple Object Access Protocol (SOAP) – Wraps XML message in SOAP envelope (XML tags) – SOAP messages are interpreted by IIS and ASP – Typically use standard and/or custom COM components in ASP pages. – Active Server Pages (ASP) are XHTML pages with embedded serverside and client-side scripts that may access COM and C# objects for a significant part of their processing. . Net Remoting 5

Web Related. Net Libraries · System. Web – System. Web. Hosting • Communicate with IIS and ISAPI run-time – System. Web. Mail – System. Web. Security • cookies, web authentication, Passport – System. Web. Services – close ties to ASP. NET • • System. Web. Services. Description System. Web. Services. Discovery System. Web. Services. Protocol – raw HTTP and SOAP requests System. Web. Session. State – maintain state between page requests – System. Web. UI – access to Web. Forms . Net Remoting 6

Remoting Architecture · · . Net Remoting uses System. Runtime. Remoting It is built on processing that supports: – Channels • A channel is a socket-based communication mechanism that can use either basic TCP protocol or the higher HTTP layer. – Activation • Activation is basically the same process that the CLR uses to create local objects. – You just have to tell the CLR what object you want. – The CLR manages its lifetime and marshals data and references back and forth, using a channel. . Net Remoting 7

Remoting Architecture . Net Remoting 8

Basic. Net Remoting – Remote Object · First create a remote-able object: – Design an object to be invoked remotely, derived from Marshal. By. Ref – Implement the class as a C# library – this creates a dll. – Any objects that you need to pass to that object need to be serializable. • The basic types like ints and strings already are serializable. • Your class objects need to have the [Serializable] attribute and contain only serializable data members. Or they can derive from Marshal. By. Ref. . Net Remoting 9

Remoting Architecture . Net Remoting 10

Basic. Net Remoting – the Server · Create a server: – Design a C# class, using a C# Console Application, or Empty Project in which you will create a Win. Form. – In a member function – main will work: • Create a Tcp. Server. Channel • Register the Channel with Channel. Services • Register the type of object clients want to use remotely by calling Register. Well. Known. Service. Type – Then, block the main thread. • The object will be created by the CLR on its own thread and remote clients will access the object through the CLR. • You don’t have to write any server code to support this access – the CLR takes care of it for you. – Create a reference to the remote-able object’s assembly, build, and run the server. . Net Remoting 11

Remoting Architecture . Net Remoting 12

Basic. Net Remoting – the Client · Create a client: – Design a C# class, using a C# Console Application, or Empty Project in which you will create a Win. Form. – In a member function – main will work: • Create a Tcp. Server. Channel • Register the Channel with Channel. Services – In a member function – main will work: • Create a proxy to access the remote component. You do this by calling Activator. Get. Object(…) and casting the result to the type of the remote object. – Note that both client and server need the assembly for the remote -able object. – Then, make calls on the remote object as needed. • You simply use the proxy as if it were the real object. – Create a reference to the remote-able object’s assembly, build, and run the client. . Net Remoting 13

Remoting Architecture . Net Remoting 14

Architecture for Project #3 · The previous slides described a classic client/server configuration. – For Project #3 we need something a little more sophisticated. • In a classic client/server only the client initiates communication. • In Project #3 you will have to have the “server” make notifications back on the “client”. – I would create a reply function that works just like the server, described earlier, except that the thread does not block after setting up the channel, but instead returns. – I would create a request function that works just like the client, described earlier. – I would have my Main function call the reply function then, as needed, call the request function. Everything else is just servicing the user interface. – I would do this for both the “client” that subscribes to notifications, and the “server” that sends out directory change notifications. . Net Remoting 15