ASP.NET 2.0: Http Compression and WebResource.axd

Another interesting issue in ASP.NET 2.0. If you use Http Compression module such as blowery, please note that in ASP.NET 2.0 this may cause an issue so all your client script validations and postbacks will stop working. You get various javascript errors like 'WebForm_PostBackOptions' is undefined. It took me several hours to figure out (hope this post will save hundreds of thousands of developers hours world wide).

In ASP.NET 2.0 all validation scripts are processed via server-side WebResource.axd handler while in ASP.NET 1.1 you can find them in aspnet_client folder. Http compression prevents WebResource.axd client side scripts to render normally (or at all ...). Excluding the path=WebResource.axd from the compression configuration solves the problem.

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So how can we do then ?

Mathieu: you can exclude the path (WebResource.axd) via web.config.

How do I exclude the WebResource.axd via web.config?

Is there any other solutions?

If you don't want to change blowery code, this is the only one that I know...

Arno: see blowery docs/samples how to exclude

I have found that to copy WebResource.axd to the root of my solution also works. Is this advisable?

Arno: Interesting. Where do you copy it from ?

From my temp internet files. My other ASP.Net 2.0 website used it, and it works fine with my problematic web site.

Arno: Sounds cool. I think it is good solution, I'm going to test it a bit. If it is good as it seems I shall blog about it and give you the credit.

Thanks, I will keep my eye on this post for your feedback :)

No, it doesn't work for me with compression :(

Yes, that might make a difference as I did not enable compression on my website.

Here is an ASP.NET HTTP Compression Module that WILL compress WebResource.axd requests.

http://www.gotdotnet.com/Workspaces/Workspace.aspx?id=2ccc1da1-e45c-401f-9b58-9b533eadb66b

Rich: Sounds interesting. But as far as I understand it is not public. How do I get the binaries and the sources ?

You just need to sign into the GotDotNet workspace. It is not unlike going to other sites where you have to login first.

Rich: Ok, I'm starting to download sources...

<excludedPaths>
<add path="WebResource.axd"/>
</excludedPaths>

Did anyone try Rich's linked solution? Does it work?

I tried it but it didn't work for me - I get the following error - still investigating this. The blowery module didnt work for me no matter what I did - I'm running DNN V4.3.5 and I get 'WebForm_PostBack' problems left and right even with Jun's work around above.

See WinFxCompressionModule Error below (should be simple enough to debug):

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[NullReferenceException: Object reference not set to an instance of an object.]
WinFxProgrammer.WinFxHttpCompression..cctor() +100

[TypeInitializationException: The type initializer for 'WinFxProgrammer.WinFxHttpCompression' threw an exception.]

[TargetInvocationException: Exception has been thrown by the target of an invocation.]
System.RuntimeTypeHandle.CreateInstance(RuntimeType type, Boolean publicOnly, Boolean noCheck, Boolean& canBeCached, RuntimeMethodHandle& ctor, Boolean& bNeedSecurityCheck) +0
System.RuntimeType.CreateInstanceSlow(Boolean publicOnly, Boolean fillCache) +103
System.RuntimeType.CreateInstanceImpl(Boolean publicOnly, Boolean skipVisibilityChecks, Boolean fillCache) +261
System.Activator.CreateInstance(Type type, Boolean nonPublic) +66
System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +1036
System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes) +114
System.Web.Configuration.ModulesEntry.Create() +41
System.Web.Configuration.HttpModulesSection.CreateModules() +203
System.Web.HttpApplication.InitModules() +219
System.Web.HttpApplication.InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers) +1251
System.Web.HttpApplicationFactory.GetNormalApplicationInstance(HttpContext context) +243
System.Web.HttpApplicationFactory.GetApplicationInstance(HttpContext context) +106
System.Web.HttpRuntime.ProcessRequestInternal(HttpWorkerRequest wr) +317

I recompiled the dll and redeployed and it works just fine - there was an attribute on the WinFxHttpCompressionModule element in the sample web.config called preferredCompressionLevel - above the comments had correctly referred to it as "maximumCompressionLevel" but hadn't taken notice first time round. Anyways, WebResource.Axd is no longer giving me a headache and my pages are 30-50% smaller than they were before.

Dave: I didn't understand. Did you use blowery or something else here ?

Where to add the excluded path in web.config file?

under "excludedPaths"

Thank you sooo much, you're a life saver!

I do not use blowery, but I'v en error: WebForm_PostBackOptions is undefined. Who help me?

How can i enable http compression, can somebody tell me i really want it. And also how smaller are my pages gonan get, en does it compress javascript and html or only html?

@Thomas:

it would compress both javascript and html
see blowery component http://www.blowery.org/code/httpcompressionmodule.html
it will help to implement compression