Store View State in a Persistent Medium, the Proper Way: ASP Alliance

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Store View State in a Persistent Medium, the Proper Way

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by Bilal Haidar
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Problems with Scott’s method

Scott did mention in his article some drawbacks for his method. Mainly, he pointed to the fact of using the Session ID to determine the file name used to store the view state. This solution will work fine in browsers that do accept session-level cookies. However, it will fail in browsers that do not support cookies because on each visit to the page a new Session ID is generated for them and this technique will break down.

However, he did mention a solution to this problem. The solution would consist of generating a GUID for each page and using the GUID together with the page name as the file name used to store the view state. Then to make sure the same GUID is used for the same page, we need to store the GUID in a hidden field inside the page.

Another challenge Scott mentioned was removing the view state files from the file system when they are no more used. He left this challenge for the readers to figure out.

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User Comments

Title: Great Article
Name: Clever Name
Date: 2012-03-30 12:33:16 PM
Comment:
I used your method and it worked great. About a month later someone told me about Page Adapters. Instead of using the default HiddenFieldPageStatePersister you can use a SessionPageStatePersister or develop your own Persister.
While the way listed in the article works using this way probably is better.

http://msdn.microsoft.com/en-us/library/system.web.ui.sessionpagestatepersister.aspx

Title: Cleanup Viewstate Files on Session End
Name: Mariner
Date: 2010-10-14 12:14:38 PM
Comment:
I like the cleanup file method that you are doing, however, I am not looking for a cleanup method that deletes the files based on a timestamp, but rather on a session end.
The reason for this is there are thousands of users accessing the site daily and there will be many viewstate files as a result. It is time and memory consuming to keep the files around based on DateTime methods.

Thank you very much for your time.

Mariner

Title: HiddenField not populated on postback
Name: M
Date: 2010-10-05 11:20:57 AM
Comment:
Hi I am trying to implement your idea in my project. However I have a problem whereby the HiddenField (vsKey) loses its value (the key GUID) when the page is posted back. Because of this the LoadPageStateFromPersistenceMedium function fails as it is returned a blank value from the vsKey HiddenField. Any ideas on this?

Your time is much appreciated. M.

Title: Re: Rudolf
Name: Bilal Haidar
Date: 2008-06-11 3:15:17 PM
Comment:
Hi Rudolf,
I am glad you liked my article!

Check the following links for compressing VS:
1. http://www.techtoolblog.com/archives/compressing-aspnet-20-viewstate

2. http://www.hanselman.com/blog/ZippingCompressingViewStateInASPNET.aspx

3. http://www.dotnetcurry.com/ShowArticle.aspx?ID=67&AspxAutoDetectCookieSupport=1

Hope they help!
Regards

Title: Viewstate with compresseion
Name: Rudolf terppe
Date: 2008-06-11 2:59:47 PM
Comment:
Hi Bilal

A perfect articel
I installedand works well.
Do you have an Idea to include compression of Viewstate?

Rudolf terppe from Germany

Title: * shudder *
Name: foobar
Date: 2006-07-29 11:17:25 PM
Comment:
There are far better ways to do this.

Go here: http://msdn2.microsoft.com/en-us/library/system.web.ui.pagestatepersister.aspx

Title: Checking for the deletion of files on every postback is bad
Name: Shoaib
Date: 2006-07-29 10:31:46 AM
Comment:
I completely agree with Kevin.

Looping through the files for deletion on every postback is bad idea. I suggest you to create a separate service for that purpose and if you have any problem working with the services, then u should use some folder hierarchy to store files like:

Year/Month/Day

so that u can delete all the folders except the one created today.

Title: Feedback on Above article
Name: Kishore
Date: 2006-07-22 8:14:20 AM
Comment:
The technique used in above article is very good but clean up files procedure is calling whenever request comes from client. I think to suggest/adopt other way around.

Title: Re:
Name: Bilal Haidar
Date: 2006-07-19 10:04:14 AM
Comment:
Keven : Marco:
Looks you two new ways which are nice too, in addition to this one.
Why don't I have a look at them both? bilal@bhaidar.net

Thanks.

Title: Don't rely on session or page to clean up files
Name: Kevin
Date: 2006-07-19 10:00:35 AM
Comment:
I think it's a very bad idea to have the page look for files to clean up and then cross its fingers and start deleting.

I also think that relying on session events at all for this is a bad idea since part of the value of ViewState is not having to rely on session at all.

Instead, you should use an HTTPModule with a Threading Timer to look for files to delete every now and again. This way, you get great reliability and you don't loop through every freakin' persisted viewstate file on every page postback.

Title: Performance Improvement
Name: Marco Dissel
Date: 2006-07-19 9:58:22 AM
Comment:
i've created i slightly different implementation:

- create GUID and store it in hidden field
- add viewstate to Cache with timespan of x minutes (no LosFormatter)
- setup delegate to cache deletion of the Cache item
- in delegate store viewstate from cache in file

on retrieval first check if viewstate still in Cache, if so return the viewstate and clear the cache for that item. If not fount load the viewstate form the file and delete the file..

Cleanup process can be done with some timer in another (new) thread..

What do you think of my approach?

Title: Atlas Ajax
Name: dadvav
Date: 2006-07-19 2:53:53 AM
Comment:
Hi, I have problem with with Atlas toolkit. I think better solution to save Viewstate ID is to use original hidden field and not own vsKey

Title: Re:
Name: Bilal Haidar
Date: 2006-07-06 12:33:07 PM
Comment:
I had several incidents where the Session_End was not fired on my machine, maybe because of VS or so, have no idea.

Thanks

Title: SessionEnd not fired
Name: Alain
Date: 2006-07-06 10:58:19 AM
Comment:
The sessionEnd event is only fired if the sessions are managed "in process" (InProc param), but not if the sessions are manages out of process (ASP.NET State Service or SQL database)

Title: Re:
Name: Bilal Haidar
Date: 2006-06-29 6:04:06 AM
Comment:
Hello:
I do use sometimes that method of having the CleanupFiles in the SessionEnd(). But sometimes it doesn't work!! Something goes wrong and the session end doesn't get fired!
That is why, to be on the safe side, I decided to place it there!

Thanks.

Title: Performance improvment
Name: Pravin Singh
Date: 2006-06-29 5:52:39 AM
Comment:
I think it is better to move the function CleanupFiles() from LoadPageStateFromPersistenceMedium() to Session_End(). In Session_End() we can find all the files with file names having the Session ID assigned to the user whose session just ended and delete them all. Because right now CleanUp() function gets called on page load of all the web forms.

Title: New Approach in ASP .NET 2.0
Name: Juan
Date: 2006-06-27 10:30:49 AM
Comment:
Check out a new article on MSDN at http://msdn.microsoft.com/msdnmag/issues/06/07/WebAppFollies/default.aspx#S4

.NET 2.0 offers an out-of-the-box way to save viewstate to session, then you could persist it in a database or in session server if you want to or just use the inproc session provider. Either way it manages the viewstate on the server for you.

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