Angry Worm

"Tape worms that escape from the bottoms of mexicans just don't know how to smile."

HTTP Compression in IIS 6.0

The things that nobody told you about HTTP compression:
1. It only works when over HTTP 1.1; however Internet Explorer's default setting is to downgrade your HTTP version to 1.0 if you're accessing the server via a proxy so even though you may think you're compressing the .aspx pages - you are not.
2. Some client programs (i.e. Adobe Reader) don't behave correctly when opening up inline documents (i.e. opening up the document in the browser window) when the content has been transferred as a chunked/compressed stream.
So, when you're testing HTTP compression, use a product like ieHttpHeaders to verify that your results are actually being compressed (you'll see headers like Content-Encoding: gzip, and Transfer-Encoding: chunked), and make sure it works with and without a proxy.

IIS Worker Process Recycling and Prime Numbers

To prevent all your application pools from recycling at the same time ... you should follow the way of the cicada! No I haven't been smoking crack. The theory goes like this: if you have two application pools recycled every M and N hours respectively (where M and N are both prime) then their recycles will only coincide every M x N hours. So, for the default 1740 minutes (29 hours) and the next prime up (31 hours), you're only going to have the problem once every 37ish days!

WindowsPrincipal.IsInRole(...) and cached SID

There is something sinister here that I'm just not getting. There is an ASP.NET 1.1 application under IIS 6.0 with an application pool set to run under the context of a domain user. The application is removed so that we can upgrade it. The domain user is added to a machine local group with additional privileges. A new version of the application is installed and started up. Somewhere in its code the line
WindowsPrincipal.IsInRole(string) is called (the parameter is the name of the machine local group), but that call fails. The event log shows a success audit for a logon attempt using explicit credentials, but the user's group membership isn't refreshed (even after an iisreset) until the machine is rebooted. If a SID is being cached, it can't be IIS that's doing it, and I'm tempted to believe it's Windows.

SELECT TOP N

To return only the top N rows in a SQL select statement, it is possible to parameterize the number N in both SQL Server 2000 and SQL Server 2005; you don't have to select the whole result set into a temporary table and whittle down the rows by yourself.
For SQL2K:
SET ROWCOUNT @NumberOfRows
SELECT * FROM SomeTableOfYourChoice
SET ROWCOUNT 0
and for SQL2K5
SELECT TOP(@NumberOfRows) FROM SomeTableOfYourChoice

NTFS Access Control Lists and Inherited Permissions

When you deploy simple changes to your ASP.NET web application / XML web service (like copying in a new web.config file) watch out for cut-and-paste versus copy-and-paste! As it turns out, copying the web.config file will allow inheritable permissions to be applied to the new object - cutting and pasting the web.config will not. If IIS_WPG loses permissions to read the web.config file you'll see the error message: "Server Application Unavailable."

XML Web Service Authentication Failures

Ok, this is just because I'm a geek. Next time you get HTTP 401 errors when you try to invoke a web service call using a Visual Studio generated proxy, don't forget to assign System.Net.CredentialCache.DefaultCredentials to your proxy's Credentials property. Also, ensure that the Windows Integrated Authentication checkbox is selected in IIS, and that the .asmx and CodeBehind files of your web service have read and execute NTFS permissions for your client user. FYI: The best practice is to assign the permissions to the folder in which the virtual directory resides, and allow the children (i.e. the asmx files) to inherit the permissions.

Look at me!

Kelly, playing for Team 3

Preparing to play croquet in the sunshine

Another Welsh river

More rivers and mountains in Wales

Wales countryside, near Llanddewi Brefi

Stoff, the reigning time trial champion

Wales, the first holiday

This is Canary Wharf 

Tower bridge 

Engine that drives the London Eye 

London eye 

Persistence of memory