.NET Remoting Versus Web Services, Page 3
ASP.NET Web Services Vs .NET Remoting
Now that we have understood the basic concepts of .NET remoting and Web services, let us identify the differences between these two technologies. For this, I present different factors such as performance, state management, etc and then identify which technology to use in what situations.
In terms of performance, the .NET remoting plumbing provides the fastest communication when you use the TCP channel and the binary formatter. In the case of Web services, the primary issue is performance. The verbosity of XML can cause SOAP serialization to be many times slower than a binary formatter. Additionally, string manipulation is very slow when compared to processing the individual bits of a binary stream. All data transported across the wire is formatted into a SOAP packet. However if your Web service performs computation intensive operations, you might want to consider using caching to increase the performance of your Web service on the server side. This will increase the scalability of the Web service, which in turn can contribute to the increase in performance of the Web service consumers. A remoting component, using the TCP channel and the binary formatter, provides the greatest performance of any remoting scenario, primarily because the binary formatter is able to serialize and deserialize data much faster.
Web services are a stateless programming model, which means each incoming request is handled independently. In addition, each time a client invokes an ASP.NET Web service, a new object is created to service the request. The object is destroyed after the method call completes. To maintain state between requests, you can either use the same techniques used by ASP.NET pages, i.e., the Session and Application objects, or you can implement your own custom solution. However it is important to remember that maintaining state can be costly with Web services as they use extensive memory resources.
.NET remoting supports a range of state management options that you can choose from. As mentioned before, SingleCall objects are stateless, Singleton objects can share state for all clients, and client-activated objects maintain state on a per-client basis. Having three types of remote objects (as opposed to one with Web services) during the design phase helps us create more efficient, scalable applications. If you don't need to maintain state, use single-call objects; if you need to maintain state in a small section of code, use single call and singletons together. The ability to mix and match the various object types facilitates creation of solid architectural designs.
.NET remoting plumbing does not provide out of the box support for securing cross-process invocations. However a .NET remoting object hosted in IIS, can leverage all the same security features provided by IIS. If you are using the TCP channel or the HTTP channel hosted in a container other than IIS, you have to implement authentication, authorization and privacy mechanisms yourself.
Since ASP.NET Web services are hosted, by default, in IIS, they benefit from all the security features of IIS such as support for secure communication over the wire using SSL, authentication and authorization services.
.NET remoting gives you the flexibility to host remote objects in any type of application including a Windows Form, a managed Windows Service, a console application or the ASP.NET worker process. If you host your remote objects in a windows service, or a console application, you need to make sure that you provide features such as fault tolerance within your hosting application so that the reliability of the remote object is not compromised. However if you do host remote objects in IIS, then you can take advantage of the fact that the ASP.NET worker process is both auto-starting and thread-safe. In the case of ASP.NET Web services, reliability is not a consideration as they are always hosted in IIS, making it easy for them to take advantage of the capabilities provided by IIS.
Both the ASP.NET Web services and the .NET remoting infrastructures are extensible. You can filter inbound and outbound messages, control aspects of type marshaling and metadata generation. .NET remoting takes extensibility to the next level allowing you to implement your own formatters and channels.
Since ASP.NET Web services rely on the System.Xml.Serialization.XmlSerializer class to marshal data to and from SOAP messages at runtime, we can very easily customize the marshaling by adding a set of custom attributes that can be used to control the serialization process. As a result, you have very fine-grained control over the shape of the XML being generated when an object is serialized.
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