What is difference between HTTP Handler and HTTP Module.

Here are the difference between HTTP Handlers and HTTP Modules.

Http Handlers:

Http handlers are component developed by asp.net developers to work as end point to asp.net pipeline. It has to implement System.Web.IHttpHandler interface and this will act as target for asp.net requests. Handlers can be act as ISAPI dlls the only difference between ISAPI dlls and HTTP Handlers are Handlers can be called directly URL as compare to ISAPI Dlls.

Http Modules:

Http modules are objects which also participate in the asp.net request pipeline but it does job after and before HTTP Handlers complete its work. For example it will associate a session and cache with asp.net request. It implements System.Web.IHttpModule interface.

HTTP Handler implement following Methods and Properties

1. Process Request: This method is called when processing asp.net requests. Here you can perform all the things related to processing request.
2. IsReusable: This property is to determine whether same instance of HTTP Handler can be used to fulfill another request of same type.

Http Module implements following Methods and Properties.

1. InIt: This method is used for implementing events of HTTP Modules in HTTPApplication object.
2. Dispose: This method is used perform cleanup before Garbage Collector destroy everything.

An Http Module can Support following events exposed to HTTPApplication Object.

1. AcquireRequestState: This event is raised when asp.net request is ready to acquire the session state in http module.
2. AuthenticateRequest: This event is raised when asp.net runtime ready to authenticate user.
3. AuthorizeRequest: This event is raised when asp.net request try to authorize resources with current user identity.
4. BeginRequest: This event is raised when HTTP Modules receive new request.
5. EndRequest: This event is raised before sending response to client.
6. Disposed: This event is raised when http modules completes processing of request
7. Error: This event is raised when any error occurs during processing of request.
8. PreRequestHandlerExecute: This event is raised just before ASP.NET begins executing a handler for the HTTP request. After this event, ASP.NET will forward the request to the appropriate HTTP handler.
9. PostRequestHandlerExecute: This event is raised when when HTTP Handler will finish the execution of current request.
10. PreSendRequestContent: This event is raised just before ASP.NET sends the response contents to the client. This event allows us to change the contents before it gets delivered to the client. We can use this event to add the contents, which are common in all pages, to the page output. For example, a common menu, header or footer.
11. PreSendRequestHeaders: This event is raised before asp.net Just send response header to client browser.
12. ReleaseRequestState: This event is raised when asp.net runtime finishes handling of all the request.
13. ResolveRequestCache: This event is raised to determine whether the request can be fulfilled by returning the contents from the Output Cache.
14. UpdateRequestCache: This event is raised when ASP.NET has completed processing the current HTTP request and the output contents are ready to be added to the Output Cache.

Hope this will help you better understanding of HTTP Handler and HTTP Modules. I will post an real time implementation code in forthcoming blog post.

Technorati Tags: HTTPHandler,HTTPModule,ASP.NET,ASP.NET RunTime,IASPI

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GUID Vs Int data type as primary key

Recently one of my friend ask me when I should go for GUID and When I should go for Int as primary key in table. So decided to write a blog post for it. Here are advantages and disadvantage of the GUID and INT.

INT Data Type:

Advantages:

1. Its required small space in terms of the storage it will only allocates 4 bytes to store data.
2. Insert and update performance will be faster then the GUID. It will increase the performance of the application.
3. Easy to index and Join will give best performance with the integer.
4. Easy to understand and remember
5. Support of function that will give last value generated like Scope_Indentity()

Disadvantages:

1. If you are going to merge table frequently then there may be a chance to duplicated primary key.
2. Limited range of uniqueness if you are going to store lots of data then it may be chance to run out of storage for INT data type.
3. Hard to work with distributed tables.

GUID Data Type:

Advantages:

1. It is unique for the current domains. For primary key is uniquely identifies the table.
2. Less chances of for duplication.
3. Suitable for inserting and updating large amount of data.
4. Easy for merging data across servers.

Disadvantages:

1. Bigger storage size (16bytes) will occupy more disk size then integer.
2. Hard to remember and lower performance with Join then integer.
3. Don’t have function to get last uniquely generated primary key.
4. A GUID primary Key will added to all the other indexes on tables. So it will decrease the performance.

Conclusion:

From above the advantages and disadvantages we can conclude that if you are having very large amount of data in table then go for the GUID as primary key in database. Otherwise INT will give best performance. Hope this will help you. Please post your opinion as comment.

Technorati Tags: GUID,INT,SQL Server2008,SQL Server

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Difference between int.Parse and Convert.ToInt32

I know this post sound basic to most of people but still lots of people does not know this. So I decided to post a blog post for this. Both int.Parse and Convert.ToInt32 are used to convert string into the integer but Only difference between them is to Convert.ToInt32 handle null and returns ‘0’ as output and int.parse is not going to handle NULL and will give a Argument Null Exception. Here is the example for that both are almost same except handling null.

          string convertToInt = "12";
          string nullString = null;
          string maxValue = "32222222222222222222222222222222222";
          string formatException = "12.32";

          int parseResult;

          // It will perfectly convert interger
          parseResult= int.Parse(convertToInt);

          // It will raise Argument Null Exception
          parseResult= int.Parse(nullString);

          //It willl raise Over Flow Exception
          parseResult= int.Parse(maxValue);

          //It will raise Format Exception
          parseResult= int.Parse(formatException);


          //For Convert.ToInt32
      
          //It will perfectly convert integer
          parseResult= Convert.ToInt32(convertToInt);

          //It will ouput as 0 if Null string is there
          parseResult= Convert.ToInt32(nullString);

          //It will raise Over Flow Exception
          parseResult= Convert.ToInt32(maxValue);

          //It will raise Format Exception
          parseResult= Convert.ToInt32(formatException);

Hope this will help you understand the better but still there is third option available called int.TryParse which can handle all kind of exception and return result as Output Parameter.

Technorati Tags: int.Parse,Convert.ToInt32,int.TryParse

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