Asp.net 4

1 What is SOAP and how does it relate to XML?

o The Simple Object Access Protocol (SOAP) uses XML to define a protocol for the exchange of information in distributed computing environments. SOAP consists of three components: an envelope, a set of encoding rules, and a convention for representing remote procedure calls. Unless experience with SOAP is a direct requirement for the open position, knowing the specifics of the protocol, or how it can be used in conjunction with HTTP, is not as important as identifying it as a natural application of XML.

2 Can you walk us through the steps necessary to parse XML documents?

o Superficially, this is a fairly basic question. However, the point is not to determine whether candidates understand the concept of a parser but rather have them walk through the process of parsing XML documents step-by-step. Determining whether a non-validating or validating parser is needed, choosing the appropriate parser, and handling errors are all important aspects to this process that should be included in the candidate’s response.

3 What are possible implementations of distributed applications in .NET?

o .NET Remoting and ASP.NET Web Services. If we talk about the Framework Class Library, noteworthy classes are in System.Runtime.Remoting and System.Web.Services.

4 What are the consideration in deciding to use .NET Remoting or ASP.NET Web Services?

o Remoting is a more efficient communication exchange when you can control both ends of the application involved in the communication process. Web Services provide an open-protocol-based exchange of informaion. Web Services are best when you need to communicate with an external organization or another (non-.NET) technology.

5 What’s a proxy of the server object in .NET Remoting?

o It’s a fake copy of the server object that resides on the client side and behaves as if it was the server. It handles the communication between real server object and the client object. This process is also known as marshaling.

6 What are remotable objects in .NET Remoting?

o Remotable objects are the objects that can be marshaled across the application domains. You can marshal by value, where a deep copy of the object is created and then passed to the receiver. You can also marshal by reference, where just a reference to an existing object is passed.

7 What are channels in .NET Remoting?

o Channels represent the objects that transfer the other serialized objects from one application domain to another and from one computer to another, as well as one process to another on the same box. A channel must exist before an object can be transferred.

8 What security measures exist for .NET Remoting in System.Runtime.Remoting?

o None. Security should be taken care of at the application level. Cryptography and other security techniques can be applied at application or server level.

9 What is a formatter?

o A formatter is an object that is responsible for encoding and serializing data into messages on one end, and deserializing and decoding messages into data on the other end.

10 Choosing between HTTP and TCP for protocols and Binary and SOAP for formatters, what are the trade-offs?

o Binary over TCP is the most effiecient, SOAP over HTTP is the most interoperable.

11 What’s SingleCall activation mode used for?

o If the server object is instantiated for responding to just one single request, the request should be made in SingleCall mode.

12 What’s Singleton activation mode?

o A single object is instantiated regardless of the number of clients accessing it. Lifetime of this object is determined by lifetime lease.

13 How do you define the lease of the object?

o By implementing ILease interface when writing the class code.

14 Can you configure a .NET Remoting object via XML file?

o Yes, via machine.config and application level .config file (or web.config in ASP.NET). Application-level XML settings take precedence over machine.config.

15 How can you automatically generate interface for the remotable object in .NET with Microsoft tools?

o Use the Soapsuds tool.