SpaceX Falcon 9 progress

Very excited to see SpaceX's progress on the assembly of their Falcon 9. Let's hope they enjoy as much success with the Falcon 9 as they have recently had with the Falcon 1.

Just for fun, here's the highlights of launch 4 again:

Mono gets some first class love in Ubuntu!

I was pretty excited to see this article on mono in Jaunty Jackalope over at arstechnica today.

It looks like there is going to be a real effort to improve Mono support in Ubuntu and migrate all applications and the CLR to the 2.0 profile.

This is fantastic news - great work Ubuntu devs!

IIS gzip compression: the missing link

I've been wanting to enable gzip compression for our static content (javascript and css files) for a while but just haven't been able to get IIS 7 to comply. Apparently static compression is enabled by default in IIS 7 but when inspecting traffic using fiddler I wasn't seeing my static content compressed.

Solution at last

After several hours of googling and trying various unsuccessful solutions I finally found the answer! Buried in the comments of a post on Rick Strahl's blog, Imad Jureidini had pointed out the following:

I've been running into the same issues. Ultimately, the solution was to change the following config setting:

<serverruntime frequenthitthreshold="1">

The default value here is "2", which means that even static content does not get compressed if it isn't requested twice within a 10 seconds period (frequentHitTimePeriod). Switching to "1" means that the file gets compressed right away.

Hopefully this will fix your problems too :)

- Imad

To confirm that this was in fact the problem I was experiencing I did a control refresh of my website several times in very quick succession. Sure enough the css and javascript files suddenly started coming through compressed.

I then used the following command to change the setting in my servers config:

%windir%\system32\inetsrv\appcmd.exe set config
-section:system.webServer/serverRuntime -frequentHitThreshold:1

After restarting IIS I tried a control refresh of the website again. As expected the css and javascript files were delivered compressed on the first request.

Why?

This begs the question - why would Microsoft do such a thing? Surely the point of compression of static resources is to reduce delivery time to the browser. Why should my users care if anyone else has recently requested the particular resource they are interested in? They aren't and shouldn't be. These static resources should be compressed first, time everytime. (The only exception to this would be where compression is straining the servers ability to serve content).

Where is the documentation?

I've got to say my experiences with IIS 7 to date have been one frustration after the next. Microsoft appears to have put a lot of work into this product and at first glance a lot of the new features look to offer real value. What I don't understand is why there is so little documentation on this new product. So much has changed from IIS 6 there really needs to be a comprehensive set of documentation available somewhere - if it does exist I have yet to find it...

We're typists first... really?

I read Coding Horror on a semi regular basis, and generally Jeff has a pretty engaging writing style and his posts are fairly interesting. I was really surprised when I read this one though.

Jeff ascertains that "We are typists first, and programmers second".

Well, I vehemently disagree. While typing ability is obviously important in the job and a necessary skill, saying that we are typists first places very little value on the technical skills required of programmers to do their job well (not to mention the years at university most of us have spent earning our Computer Science degrees, Masters and in some cases PhD's!).

Personally I don't even like the label "Programmer". I feel it undervalues the skills I have. Software Engineer is far more accurate description of the job most of us do. Writing a non-trivial application these days requires an understanding of many challenging concepts.

Todays Software Engineers need to consider concurrency issues, network theory, efficient persistence mechanisms, efficient search algorithms (the volume of data we are dealing with is growing exponentially), but to name a few.

Let's not sell ourselves short by calling ourselves programmers.

Returning to Jeffs' typists first allegation though, one comment on his post summed it up nicely for me:

I’ve always really liked your blog Jeff, but this is a BS post

Thoughts?

MooTools slide effect and Internet Explorer CSS

Have you struck a problem with MooTools slide transition and CSS styles not appearing correctly in IE? I ran into this exact issue the other day where I was trying to slide a DIV element up and down based on a click event elsewhere on the page. The CSS style applied to the DIV looked something like this:

#slidingDiv {
    padding-bottom: 10px;
    background: white url(../images/box_bottom.gif) bottom no-repeat;
}

The problem seems to be that IE can't calculate the height of content in the dynamically resized DIV correctly and thus the padding-bottom and hence my background image (nice rounded corners in this case) wasn' showing.

The solution

The fix turned out to be simple enough, I just made the height of the DIV fixed in the CSS. Once IE knew how big the inner content was supposed to be everything started working correctly.

The Big Bang Theory, the best thing on TV right now?

If you haven't yet seen The Big Bang Theory you should make an effort to rectify the situation immediately. It really is an excellent show based around intelligent witty humor rather than cheap laughs and tremendously funny.

The story focuses around two ubergeeks, Leonard and Sheldon and how their life changes when they meet Penny their new "normal" (and very pretty) neighbor. I love the fact that the show celebrates the geeky, ultra intelligent side of their characters and although most of the laughs come from their lack of ability to deal with normal every day social situations, the writers do it in such a way that is funny without making Leonard and Sheldon the butt of every joke.

The Big Bang Theory manages to mix in enough scientific content and references to keep us geeks happy while still being incredibly watchable and entertaining for those with less of a penchant for things science.

Check out a few snippets from the first show of season one:



If you haven't seen season one it's already out on DVD, grab your copy now, you won't be disappointed!

RowUpdating event and UpdateRow method of a GridView not firing

We struck a bit of an odd problem today. We had an older ASP.NET 2.0 website we were migrating to ASP.NET 3.5 and one of the pages has a GridView on it. As we use Spring.NET and NHibernated Microsofts new objectdatasource approach for binding the GridView won't fly so we were using old school databinding. This meant we needed to be able to handle the RowUpdating event in order to persist our changes. The problem was that the RowUpdating event just wasn't firing.

Eventually we tracked it down to a weird interaction between Spring.NET and the GridView where if we wrapped the GridView in a spring:panel and suppressed dependency injection the event started firing. Of course the new and old values that are supposed to be available in that event handler were still null...

There is obviously a bug with the databinding in the GridView somewhere and it seems Microsoft is aware of the issue, however I wouldn't hold my breath for a fix to be forthcoming.

Personally I think the new objectdatasource model has some serious drawbacks and the fact that Microsoft haven't made the effort to ensure that custom databinding still works is a real shame to say the very least!

NHibernate onFlushDirty has null previousState

The problem

We use an Entity interceptor to create audit records when we update most tables. We also do a lot of our data access through .NET remoting. This means that we open a session to load the object, the object is detached, serialized, modified, then reattached to the session when we want to persist the changes.


We noticed that in the cases where we are updating detached objects, although the update was being applied correctly there were no audit records appearing in the database. On investigation we realised that the previousState parameter passed into the onFlushDirty method of our interceptor was null.

Why

In the Save method of our data access class we were using the SaveOrUpdate method of the NHibernate session to persist the changes. Section 10.7 of the documentation states:

saveOrUpdate() does the following:

• if the object is already persistent in this session, do nothing
• if another object associated with the session has the same identifier, throw
  an exception
• if the object has no identifier property, save() it
• if the object's identifier has the value assigned to a newly instantiated
  object, save() it
• if the object is versioned (by a or ), and
  the version property value is the same value assigned to a newly instantiated
  object, save() it otherwise update() the object

and merge() is very different:

• if there is a persistent instance with the same identifier currently
  associated with the session, copy the state of the given object onto the
  persistent instance
• if there is no persistent instance currently associated with the session,
  try to load it from the database, or create a new persistent instance
• the persistent instance is returned
• the given instance does not become associated with the session, it remains
  detached

As our detached objects had an Id and version when we called SaveOrUpdate() they were being updated, and seeing as all update() does is reattach an object to the session, the session had no record of the changes that had been made to that object since it was loaded.

The solution

The solution was to use the merge() method (new in NHibernate 2.0). Merge() checks the first level cache to see if an object with the given identifier has previously been loaded. If so it loads that object out of the first level cache and updates it's properties using the detached object. This means that the session is now able to track the changes made to the object so that when the flush occurs the previousState is no longer null.

MooTools ASP.NET Webservice Ajax calls.

I had some trouble trying to find an example of how to call an ASP.NET webservice from MooTools. I eventually pieced the bits together from a couple of forum posts and thought I'd post an example here in case anyone else was having the same problems.

If I have an ASP.NET webservice that has a GetById method that takes a single int parameter and returns an object I can call it with the following code:

function doAjaxWebServiceRequest (id) {
var completeDelegate = Function.createDelegate(this, this.callback);
var failureDelegate = Function.createDelegate(this, this.error);
var request = new Request.JSON({url: 'http://hostname/MyWebService.asmx/GetById',
onComplete: completeDelegate,
onFailure: failureDelegate,
urlEncoded: false,
headers: {"Content-type": "application/json"}
});
request.send(JSON.encode({'id': id}));
},

The returned object will be in JSON format. The lines where I create my callback delegates using the Function.createDelegate method allow me to set the scope of 'this' in my call backs to be the object I making the request from.

Hope that helps someone out!

Mootools differences in IE and Firefox

We're using the MooTools scripting framework on our site and today I discovered a strange difference between Firefox and IE. I was creating an element and injecting it into the DOM and then trying to change its CSS class and styles.

addClass and setStyle
MooTools provides methods on it's Element class that allow you to manipulate the CSS styling of an element. You can do things like:

// Add a css class to the element with the id foo
$('foo').addClass('fooStyle');

// Set the width of the foo element
$('foo').setStyle('width', '100px');

Unfortunately when viewing an ASP.NET page in IE that includes a script that uses these functions you get a script error saying that the "Object doesn't support this property or method"

At first I thought the solution was to go back to basics:

// Add a css class to the element with the id foo
$('foo').className = 'fooStyle';

// Set the width of the foo element
$('foo').style.width = '100px';

However I then realised that I was trying to call the MooTools Element methods on a vanilla element object rather than a MooTools one. The second line below solved the problems in IE and meant I could go back to the first way of applying the styling.

var myelement = document.createElement("a");
myelement = $(myelement);

IE vs Firefox
In retrospect it seems strange that this worked in Firefox, I guess Firefox must be able to do some sort of implicit conversion to a MooTools element in order to resolve the method call.

MooTools seems really great, it's lightweight and easy to use. The learning curve seems much lower than some of the other more complicated offering available.

The only reservation I have at this point is that from what I've read on the forums it doesn't play nicely with any other scripting framework due to it's lack of namespaces and the maintainers seem quite hostile to anyone who suggests that would be a good thing.

NMock and out parameters

While trying to create a unit test the other day I came across the situation where my mock object needed to return a value via an Out parameter. A quick google turned up this post over at dev:ices.

I thought that had answered all my questions but when I tried it I kept getting a very unhelpful error:

------ Test started: Assembly: Tests.dll ------

TestCase 'Tests.BatchOrderMessageHandlerTests.TestNMock'
failed: NMock2.Internal.ExpectationException : unexpected invocation of foo.DoFoo(<1>, <1>, out)
Expected:
1 time: foo.DoFoo(equal to <1>, equal to <1>, equal to ), will set c=<2>, return <1> [called 0 times]
at NMock2.Mockery.FailUnexpectedInvocation(Invocation invocation)
at NMock2.Mockery.Dispatch(Invocation invocation)
at NMock2.Mockery.MockObject.Invoke(Invocation invocation)
at NMock2.Monitoring.Invoker.Invoke(Invocation invocation)
at NMock2.Monitoring.ProxiedObjectIdentity.Invoke(Invocation invocation)
at NMock2.Monitoring.ProxyInvokableAdapter.Invoke(IMessage msg)
at System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type)
at Tests.BatchOrderMessageHandlerTests.IFoo.DoFoo(Int32 a, Int32 b, Int32& c)
C:\svn\GLGParnters.TradeIdeas\PositionManager\src\Tests\BatchOrderMessageHandlerTests.cs(136,0): at Tests.BatchOrderMessageHandlerTests.TestNMock()

0 passed, 1 failed, 0 skipped, took 0.77 seconds.

A bit confused I quickly whipped up a trivial test as my unit test was a bit complicated and returned an enum as the Out parameter. My hypothesis was that NMocks couldn't return an enum as an Out parameter.

public interface IFoo
{
int DoFoo(int a, int b, out int c);
}


[Test]
public void TestNMock()
{
IFoo foo = _mockery.NewMock();

Expect.Once.On(foo).Method("DoFoo")
.With(1, 1, Is.Out)
.Will(new SetNamedParameterAction("c", 2), Return.Value(1));

int result = 0;
int a = foo.DoFoo(1, 1, out result);

_mockery.VerifyAllExpectationsHaveBeenMet();
Assert.AreEqual(2, result);
}

This also failed so I checked what version of NMocks I was using. My NMock2.dll assembly had a revision number of 1.0.2313.18049. I downloaded the latest binaries from the NMock website. Checking the version number of the latest build shows it to be 2.0.0.44.

Rerunning the unit tests against this version of the NMock library everything now works!

So, if you're having trouble with out parameters in your NMock mocks, upgrade your build version.

NHibernate 2.0 and the join table syntax

I've noticed my post on Mapping a view with NHibernate is always quite popular. Resorting to mapping from a view has worked fine in the past as long as you only required read access, but if you wanted to build a complex object relational mapping that you could update you were in trouble...

Until Now

With NHibernate 2.0 recently being released we now have access to the join table syntax in our mapping documents. This means we can now build more sophisticated domain objects that map on to more than one table. NHibernate takes care of the multi-table inserts and updates behind the scenes making your life easier.

This has to be one of the most underrated features of NHibernate 2.0 as it finally allows you to break away from the one to one mapping between domain objects and your relational model which has ultimately caused compromises in the past.

I urge you to check out this and the other fantastic new features available in the latest NHibernate release.