Wednesday, November 26, 2008

WCF Tracing with SvcTraceViewer

I had a problem with an WCF Service that I'd written that was reading from an MSMQ and would blow up if the message was larger than 64K. Once I'd tracked down the exception that was being thrown (QuotaExceededException) a quick search on Google with "wcf quotaexceededexception" landed me on Hugo Batista's blog site and his WCF: maxReceivedMessageSize and QuotaExceededException post which was exactly what I was experiencing and this solved the problem.

This, however, did not solve the problem of how incredibly difficult I found it to log that QuotaExceededException exception. Like Hugo Batista I'd tried to catch the UnhandledException event from the AppDomain but this was unsuccessful.

Eventually I discovered that I could turn on Message Logging and Tracing in the App.config file and then use the SvcTraceViewer application to look at those files. This worked a charm and the tools make it pretty easy.

First you need to edit the App.config file but Visual Studio 2008 has a utility that makes this very easy for WCF. Right click on the App.config file and you will see an option "Edit WCF Configuration." This brings up the Microsoft Service Configuration Editor which makes editing this much easier. In the Configuration section on the left hand side click on Diagnostics and then click on the links "Enable MessageLogging" and "Enable Tracing" and set the locations for the log files.

Now run the errant web service and once it's faulted the channel open the error file with SvcTraceViewer. I found SvcTraceViewer in the "C:\Program Files\Microsoft SDKs\Windows\v6.0A\bin\" folder on my XP machine. The tracelog is where you'll find the warnings etc.

Tuesday, November 25, 2008

Jon Skeet is better than Chuck Norris

 A coworker of mine brought the Jon Skeet Facts question to my attention a few days ago and I laughed out aloud when I read it. Subsequently Jeff Atwood blogged about it in Stack Overflow Is you.

The icing on the cake, for me at least, is Jon Skeet's sense of humor in writing the accepted answer in the third person. Very funny.

Friday, November 21, 2008

The difference between Tempuri and Tempura

If you've ever worked with a web service that started off life being generated by a Microsoft tool then you've probably seen the namespace I've seen this for years and I know it well. I also know that you're supposed to change it immediately but that hardly anybody does.

Until today, I had no idea why it was called I thought that maybe it was some fictional company like Contoso that a Japanese employee from  Microsoft who loved tempura style deep-fried cooking had made up to stick in the namespace.

The along came a friend of mine and pronounced it as Temp URI, and suddenly it all fell into place.

Monday, November 17, 2008

Microsoft JScript runtime error object expected with jQuery

I was trying to get a simple piece of jQuery to work and was running up against this error in Internet Explorer (IE):

Microsoft JScript runtime error: object expected

The problem turned out to be that I wasn't referencing jQuery to the correct path. The trick I discovered, if you're using Visual Studio, is to just drag the JavaScript file from the Solution Explorer into the <head> element on your page and it will insert the correct reference for you.

UPDATE (9 July 2009):

I am referencing jQuery from the Google CDN now:

<script src=""></script>
        google.load("jquery", "1.3.2");
        google.load("jqueryui", "1.7.2");

Using this technique will also get rid of this error and improve performance.

The first reference to jQuery (1.3.2) is for the core jQuery library. The second reference to (1.7.2) is for the optional jQuery UI library that you will only need if you are using the UI components/elements of the jQuery library. If you are using jQuery to manipulate the DOM only then you won't need the UI reference.


Sunday, November 16, 2008

NoIndex NoFollow

I was just using Google to search Stack Overflow and came up with the following search results:

If you click on the second, third, or fourth items in the search results and then search the page for the term jscript you will find that it's not there. That's because when Google indexes the "hottest" part of Stack Overflow the jscript question was on the page but this is a volatile page and the links from this page change frequently.

Personally I find it annoying when I arrive at an dynamic index page on a site (via Google) only to find that the search term has subsequently been bumped off the list.

Should we do anything about this? And if so, what can we do about this?

First off, I think that you should not have Google index this page. If you have this keyword on your site then let Google focus its results on the page that has this keyword and that talks about this keyword. Spreading a keyword widely across a site is going to dilute its effectiveness and degrade user experience when they visit the site looking for that information.

On the Google Toolbar bar in IE there's the option to enable the happy and unhappy faces to vote on a page when you land there. I don't believe that Google uses this information however it does give me satisfaction when I land on an indexed page which doesn't have the search keyword on it to be able to click the unhappy face.

The obvious exception to this is if you have a stable, non-volatile index which will always have the keyword on it. Although this will not be as effective as landing the user on the content page because it will still require the user to find the link on the landing page and click through.

The way that I accomplish this in C# on my ASP.NET web sites is to set the robots meta tag as such:

I do this by using a common base class for all my pages. Here's a subset of the code from the base class:
public class CommonPageBase : System.Web.UI.Page
    public void SetNoIndexNoFollow()
    public void SetNoIndex()
    public void SetNoFollow()
    private void SetRobots(string content)
        HtmlMeta robotsMeta = new HtmlMeta();
        robotsMeta.Name = "ROBOTS";
        robotsMeta.Content = content;

Then in the code behind page for the .aspx page the Page_Load function will look something like this:
public partial class MyPage : CommonPageBase
    protected void Page_Load(object sender, EventArgs e)

You may of course want to make the call to the SetNoIndex() function conditional on an isVolatileIndex type variable. 

Podcasts for Developers

I'm now struggling to find good developer focused podcasts to listen to. When I first discovered Hansel Minutes there were already 109 archived episodes so that kept me busy for several months. Thank you Scott Hanselman. At about the time that I ran out of Hansel Minute podcasts, Jeff Atwood and Joel Spolsky started their Stack Overflow Podcasts. At first I was not that impressed (the first couple of episodes) but I have subsequently become a big fan and it has now pushed Hansel Minutes into second place on my favorites list. This is probably because of Spolsky's arrogant and confrontational personality (this is a good thing) along with his sense of humor. He doesn't hold punches when verbally sparring with Atwood. Although Carl Franklin now makes rare appearances on Hansel Minutes when the two of them were on the air they were too polite to each other to make the conversation as engaging as the Spolsky/Atwood combo. This is a relative comparison though - don't misunderstand me because I still think that their conversations are A-grade and would listen to them anytime.

I've been working my way through the "My developer podcast" (link removed because broker) list on Code de Mora but haven't heard anything on that list that really engages me like the other two do. I've also found a number of podcasts on IT Conversations which I've downloaded but not listened to yet.

So here is my current list of podcasts in favorite order (to be edited when I find more or my preference changes):

Scott Hanselman created a List of Podcasts for .NET Programmers on 9 Feb 2009. He also said "If you've created a list of YOUR favorite .NET Podcasts, send me a link to your blog and I'll add it here" - however, if I did that then you'd end up in an infinite loop.

jQuery Select Notes

class: e.g. <p class="me"> text</p>
jQuery: $('.me')

id: e.g. <p id="me">text</p>
jQuery: $('#me')

element: e.g. <p>text</p>
jQuery: $('p')

elements inside id's: e.g. <ul id="me"><li><a>...
jQuery: $('#me a') will select all the anchor elements <a> under that <ul> tag.

elements inside elements (child tags): e.g. <html><p>text</p></html>
jQuery: $('body > p')

elements next to elements (siblings)
jQuery: $('p + div')

elements with attributes: e.g. <img src="..." alt="..." /> 
jQuery: $('img[alt]') will select all <img> tags with an alt attribute
$('a[href]') will select all anchor tags with an href attribute and thereby exclude named anchors: e.g. <a name="jumpToMyLocation">

elements with attributes having specific values
exact value: $('input[type=text]') will select all input tags with an attribute of type set to text.
starts with: $('a[href^=mailto:]') will select all anchor tags that have an href attribute set to a value that starts with 'mailto:'.
ends with: $('a[href$=html]') will select all anchor tags that have an href attribute set to a value that ends with '.html'.
contains: $('a[href*=content]') will select all anchor tags that have an href attribute set to a value that contains the text 'content'.

filter with : (colon)
$('tr:odd') will filter the <tr> selection from a table by the odd rows using a zero based index for the <tr> tags.
$('a:not([href$=html]') will filter the anchor selection by excluding all anchor tags with href attributes that end in 'html'.
$('li:has(a)') will filter the <li> selection by <li> elements that have <a> elements as child elements. This will result in a collection of <li> tags and not <a> tags.
$('a:contains(click here)') will filter the anchor tags which have the text 'click here'.
$('div:hidden') will get all the <div> tags that are hidden.
$('div:visible') opposite of $('div:hidden')

Friday, November 14, 2008

Team Wiki

We have a team wiki for our development team. It's sometimes difficult to decided what goes into the wiki.

I have a rule that after I've been asked the same question three times by a co-worker I put it in the wiki.

How do you decide what goes in your team wiki?

Hacking attempt

I've noticed the following trailing URL logged as an error by IP's of dubious origin on one of my sites:


The hacker-bot attempted the same URL about 20 times using proxies from the UK, Netherlands, Australia, Poland, USA, Japan, China, Malaysia, and Germany. It had multiple different proxies in almost all those countries so each of the 20 IP's were unique.

I'm wondering what security hole are they trying to exploit?

Tuesday, November 11, 2008

Cloud Computing Defined

When the internet is included in an architecture diagram of a system it is almost always depicted as a cloud. The cloud refers to applications and operating systems running on remote computers accessible locally and usually via the web.

Previously cloud computing was called:

  • Software as a Service (SaaS)
  • Client / Server
  • Time Sharing

Should I have called this mini-post "there is nothing new under the sun?"

Monday, November 10, 2008

LINQ to XML Resources

This is a collection of LINQ to XML Resources that I've found useful.

Daniel Moth has a great diagram and explanation of the System.Xml.Linq namespace.

Hooked on LINQ's five-minute overview.

Microsoft's LINQ to XML Overview.

Hansel Minutes LINQ to XML podcast.

Joseph Albahari's excellent LINQPad utility can be used to visualize the workings of LINQ to XML. Plenty of samples in this application.

Scott Guthrie on how to build a custom RSS Feed Reader with LINQ to XML.

Typed XML programming by using LINQ to XSD.

Transforming with LINQ to XML.


Sunday, November 9, 2008

lsass.exe and SQL Server pegging CPU at 100%

Had an unusual problem with an MS Server 2003 today. The CPU was being pegged at 100% every 15 seconds for about 12 to 14 seconds. When I examined the Processes with Task Manager it showed that lsass.exe was the culprit and that its accomplices were sqlservr.exe and w3wp.exe.

This happened shortly after a deployment of a web site to the server that had been built on an x64 Server (2008) but deployed to an x86 Server (2003) - so I was considering this as a possible problem however I knew that I'd compiled the ASP.NET web app to target any CPU.

I found numerous references on the web to lsass.exe causing problems and also found this hotfix from Microsoft which I installed but it did not help: (when I say that it did not help I mean that it did not immediately fix the problem although it could have later added to a resolution by being there.)

After further hunting and examining event logs and server logs and disabling and stop and starting differenct web sites on the server I narrowed the problem down to one particular web site. This web site is an ASP.NET web app but also has a ASP Snitz forum in one of the sub-folders.

I tried taking the web site offline with the App_Offline.htm file and noticed that unlike when I stopped the web app the problem was still there. So I checked the forum and noticed that App_Offline only works with the ASP.NET part of the site and not the ASP part of the site.

This gave me a breakthrough in the hunt for a solution because I'd managed to separate the ASP and ASP.NET code and determined that it was the former. So I deleted the App_Offline.htm file and went into the forum admin page and took down the forum. The CPU usage immediately returned to normal and the pegging at 100% by lsass.exe and the others stopped.

Even though I'd isolated the problem to a small area I still didn't know what was causing this. Now this is the frustrating part: I switched the forum back online and the problem dissappeared. The CPU usage is back to normal and the problem gone. Although I'm happy that that problem's gone I'm frustrated that I don't know what caused it and fearful that it will return again.

Remember that I rebooted this server after I installed the MS KB patch metioned above which would have obviously stopped and restarted the web app and the forum code as well so I don't think that it was just a matter of stopping and starting it.

Friday, November 7, 2008

VS2008 Object Test Bench

My amazingly talented co-worker Dan Esparza showed me the Object Test Bench in VS2008 which I never knew about until today. Looks like a productive tool:

If you want to test an object and invoke its methods then you can instantiate a class directly from the VS2008 IDE and call its methods.

  • Open the Class View in your project and right click on a class and select Create Instance... and then select the constructor from the sub-menu (there'll only be one option if you don't have a constructor or a single constructor).
  • The Object Test Bench window will open and the instantiated object will be in that window.
  • Right click the object and select a method to invoke on it.
  • If you have a break-point on the object then execution will stop there and you can inspect the values etc.

The only oddity I've seen so far is that it will only work on class in the start-up project. More info here...

Wednesday, November 5, 2008


I was listening to Scott Hanselman's MSR at PDC podcast and he discussed a tool called Chess which is designed to work with Team MSTest in VS2008 to track down Heisenbugs. I'd never heard of this type of bug being called a Heisenbug before but have experienced it plenty. Simply stated, a Heisenbug is a bug that dissappears when the code is run through the debugger.

The name Heisenbug appropriately comes from the Heisenberg uncertainty principle which states that the position and momentum of a particle cannot both be known simultaneously.

I loved Hanselman's Heisenberg joke:

Heisenberg get's pulled over by the police.
Officer: "Do you know how fast you were going?"
Heisenberg: "No, but I know exactly where I am."

Sunday, November 2, 2008

CPUID Hardware Monitor

Ultramaroon put me on to the CPUID Hardware Monitor. This is how my machine is currently running: