Interview Questions Part 6 - WCF , Cache , HTPHandler , HTTPModule

Interview Questions Part 6 - WCF , Cache , HTPHandler , HTTPModule

Question 1 :
Which namespace does Cache object belong to ?

Answer 1 :
Cache object belongs to System.Web.Caching namespace.

Question 2 :
Explain WCF callback behaviour ?

Answer 2 :
Call back behaviour is similar to Service behaviour . They control endpoints created on client in duplex communication.

Question 3 :
Explain WCF Operation behaviour ?

Answer 3 :
Operation behaviour are scoped at Operation level. It is used for transaction flow , serialization , parameter handling.


Question 4 :
Explain WCF Endpoint behaviour ?

Answer 4 :
Endpoint behaviour are defined at endpoint level. They are used for inspecting and taking actions on messages as they come in and out of service.

Question 5 :
Explain WCF Service behaviour ?

Answer 5 :
Service behaviour run at service level and have access to all endpoints. They control instancing and transactions. They are also used for authorization and auditing.

Question 6 :
State different types of primary WCF behaviours ?

Answer 6 :
Different types of primary behaviours are as follows :

1. Service Behaviour
2. Endpoint Behaviour
3. Operation Behaviour
4. Callback Behaviour

Question 7 :
What is the impact of IsReusable property in HTTPHandler?

Answer 7 :
IsReusable property can be set to true or false.
If set to true then IHttpHandlerFactory object ( object which calls handler ) can place handler in pool and reuse it for better performance. If set to false , new instance must be created each time handler is needed.

Question 8 :
How to create custom synchronous HTTPHandler ?

Answer 8 :
Steps to create custom synchronous HTTP Handler :

1. Implement IHttpHandler interface
2. Implement ProcessRequest mehtod and IsReusable property
3. Register handler in Web.config
4. Add file name extension mapping to ASP.NET in IIS

Question 9 :
State few built in HttpHandler in ASP.NET

Answer 9 :
Few built-in httphandler in ASP.NET are :

1. ASP.NET Page Handler - handler of all .aspx pages
2. Web Service Handler - handler of all .asmx
3. ASP.NET User Control handler - handler of all .ascx
4. Trace Handler - for trace.axd

Question 10 :
How do I add public events for Httpmodule in Global.asax ?

Answer 10 :
You can add public events for Httpmodule using below syntax i.e
ModuleName_OnEventName in Global.asax .

Example

Session_OnStart ( Object sender , EventArgs e ) in Global.asax defines event handler for Start event of SessionStateModule