NU – gem like packaging for .NET

by DotNetNerd 26. July 2010 20:37

I just had a look at NU which is made to be for .NET what gems are for Ruby. Why should you care? Well if you are like me downloading new versions of miscellaneous open source projects and updating them along the way is not your favorite thing. It’s just tedious and seems to be a hassle for something so basic. This is where NU gives you a hand.

If you have IronRuby running simply open an command line and type:

igem install nu

Then when the installation is done go to the root of your projects folder (eg. D:) and type:

nu install <some_gem>

I started out running “nu install nunit” and “nu install nhibernate” and in less than a minute I had nunit, unhibernate, log4net, castle.core and castle.dynamicproxy2 unpacked to D:\lib like this.


Like a good handyman a developer needs his tools – and plugins

by DotNetNerd 23. July 2010 17:34

Over the last couple of weeks I have been looking at quite a few new frameworks, tools and plugins. My focus area has mainly revolved around an app that I will be building that needs to pop and therefore it will make pretty heavy use of javascript and css - and of course by extention jQuery.

First of all dotLessCss deserves a mention, even though its actually not one things I looked at now. Basically it allows you to do some of the stuff you probably miss when working with css. Variables, mixins and nesting really helpes reduce all the repetitiveness. SquishIt is a little library I read about a while ago. It makes bundeling and minimizing javascript and css files as easy as can be. On top of that it also makes sure the files get versioned, so you won't run into users running on an old cached version.

In the category nice jQuery plugins I have looked at quite a few things. jQuery cookie addin makes it a no brainer to work with cookies. Watching a video from NDC I learned that newer browsers now support other ways of saving data on the client called sessionStorage and localStorage. As always the problem is compatibility, but there is a shim to fix this for IE6 and IE7, which are the main culprits.

I also looked at a few flashy jQuery addins, and FancyBox and Cycle solve a few of the things designers crave these days while being super simple to implement. Now that we are in the design department Cufón helpes you do font replacement easily, so you can use cool non websafe fonts.

Video is an area where there are quite a few options available, and it is becomming a jungle figure out which players support which formats and run in which browsers. Video for everybody is a simple way to implement videos in a way that will work across all the popular browsers. The idea is to use the html 5 video tag and then default to others where it is not supported. If being crossbrowser is not quite that important but designing the player is Silverlight has some great optios as well as flowplayer. Both are also easy to work with from javascript almost as straight foreward as the html 5 player API.

Lastly I saw a tweet about TopShelf and decided to try it out. Safe to say, I'll probably use it everytime I need to write a Windows Service from now on. It makes it just a little easier, and allows you to run your app either in a console or as a windows service.


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IronRuby 1.1 with LINQ support

by DotNetNerd 20. July 2010 08:37

Finally LINQ is supported in IronRuby now from v. 1.1 and I think it has been solved quite elegantly without any real syntactical gooeyness. Trying it out has been made very straight forward by looking at the 101 LINQ samples rewrite for IronRuby.

From day one LINQ has seemed a natural fit with IronRuby already having a similar approach with functions such as .each {|item| ...} which is accessible on anything that can be enumerated - very much like a big part of LINQ is extentions methods to the IEnumerable interface. No doubt there has been some challanges around how to map generics, extention methods etc between the languages, but syntactically it seems a natural fit.

products.where(lambda { |p| p.units_in_stock > 0 and p.unit_price > 3.00 }).each { |x| puts x.product_name }

Combining functional methods from LINQ with the existing Ruby methods just makes the "Integrated Query" syntax even better. So now we get a .each method with LINQ even though Microsoft originally didn't want to include it :)


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IronRuby and hashes in metaprogramming

by DotNetNerd 29. June 2010 19:39

This will probably be one of the shortest blogposts I'll ever write, and probably the one with the least amount of code - besides an occational rant. The reason is that like pictures sometimes say more than a 1000 words, so does elegant code.

module MyModule
class MyClass
def write_stuff text
puts text

m =
actions = {:write_stuff => "Hello action packed world!"}
actions.each {|key, value| m.method(key).call(value) }

It might just be me who is weird - but I think this way of doing eg. a strategy pattern is pretty cool.


Ajax-enabled WCF services and loadbalancing

by DotNetNerd 10. June 2010 20:35

This week I ran into a problem when we were deploying a webapplication that uses ajax-enabled webservices to an environment that uses loadbalancing. The services were running fine in the stage environment and when each of the servers were called directly, but as soon as we went through the loadbalancer they failed.

I started by checking if the svc files could be reached, and surely enough they could be accessed from the servers, but through the loadbalanced domain I got a 404.

Reading blogposts on the subject provided little help – well actually it just hightened my degree of confusion. So after some time I started thinking about IIS bindings. I remembered that I had written a custom WebScriptServiceHostFactory because we had several bindings which IIS doesn’t handle too well.

using System;
using System.Configuration;
using System.ServiceModel;
using System.ServiceModel.Activation;

namespace MySite.ScriptingService
    public class MyCustomHostFactory : WebScriptServiceHostFactory
        protected override ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
            //This makes it possible to control which binding is used by sorting them in IIS.
            return new ServiceHost(serviceType, baseAddresses[int.Parse(ConfigurationManager.AppSettings["BindingIndex"] ?? "0")]);

I started playing around with which binding we used, and as I suspected if the binding was not the one for the loadbalanced domain it returned the 404. This was one of those “doh!” moments. I still had a problem though, because the site could be accessed both with and without the www subdomain. A colleague pointed to the fact that we could use the URL rewrite plugin for IIS, and have it ensure all traffic was directed through one of the domains. As it turnes out it actually has a CanonicalHostNameRule that does just this because its a SEO good practice. Only issue I had left was that umbraco on the other hand has a practice that it must be accessed directly on one server, so changes are made on the master and replicated to the slave(s). This just required extending the conditions so it does not redirect if the umbraco folder is part of the path.

IIS routing

So now by posting this I hope Ill save someone else from getting a few extra gray hairs, and if not maybe I’ll save my self some other time when I can’t remember how I did…

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Hello rake-world

by DotNetNerd 27. May 2010 16:31

Rake is a quite popular build framework, that has its strengths in the fact that it is code (no more xml), and it is very simple to get started with. Actually setting it up is a 3 step process.

  1. Make sure the path environment variable is set to point at your ironruby/bin folder.
  2. Run “igem install rake” from the commandline
  3. Write a Rakefile.rb like the following and place it at the root of your site

require 'rake'

task :default => [:say_hi]

desc "Does quite a bit of greeting"
task :say_hi_to_me do
    puts "Hello me. Now that was easy."

task :say_hi_to_world do
    puts "Hi world!"

task :say_hi => [:say_hi_to_me,:say_hi_to_world] do
    puts "I’m, all hellowed out"

This really all it takes, so now you are ready to run your tasks from the commandline by writing: “rake” or “rake say_hi_to_me”.

Now for this to get really interesting you will need albacore which makes it easy to do all kinds of basic tasks.

This is installed with the command “igem install albacore”, and makes it possible to do builds and run unittests like this:

require 'rake'
require 'albacore'

task :default => [:full]

task :full => [:clean,:build_release,:run_tests]

task :clean do
    FileUtils.rm_rf 'build_output'

msbuild :build_release do |msbuild| :configuration => :AutomatedRelease
  msbuild.targets :Build
  msbuild.solution = "TestApp/TestApp.sln"

nunit :run_tests do |nunit|
    nunit.path_to_command = "tools/nunit/nunit-console.exe"
    nunit.assemblies "build_output/TestAppTests.dll"


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Silverlight and IronRuby – a match made in heaven

by DotNetNerd 25. April 2010 10:31

A couple of months ago I was starting to read about IronRuby, and while thinking about what my first little pet project should be I saw a tweet from a guy who was enjoying the combination with Silverlight. I gave the idea some thought and liked the idea of using a dynamic language to make a rich internet application. So after reading IronRuby UnleashedI started out doing a version 2 of my site – which is just a little toy selfpromotion site.

Getting started was pretty straight forward because with IronRuby there is a small webserver called Chiron, which can make a project template. All you have to do is open a cmd, and go to the library where IronRuby is installed and type script\sl.bat ruby <projectpath>

Armed with my starter template I began playing around and got my layout in place. I also tried using some 3rd party components by referencing some dll’s and all that basic stuff. Most of it went smoothly, but I did run into an assembly ( that threw an exception when used with Silverlight/IronRuby. Using it from a console project in IronRuby worked fine, so I quickly decided to just go directly against the flickr api using the .NET WebClient class. Running the site from chiron was as easy as calling script\chr.bat /d:<projectpath> /b:index.html

When I had the first couple of pages ready and had written a picturegallery showing the last 5 pictures I have uploaded to flickr I wanted to get the site deployed, so I would no longer depend on chiron. From my book and by looking at blogs it seemed to be smooth sailing, because chiron has a function that makes a .xap file which is all you need. To my surprise when I referenced the .xap file from the html file in my my project it looked like it loaded, but then just stopped at 100% without showing my actual site. I felt pretty stuck, because I had no exception or anything to go on, and my site ran fine when I was using chiron.

I then wrote an email to “Iron” Shay Friendman, who wrote the book that I was using as my inspiration. I thought it was worth a shot, and that I could not be the only one with that problem. Later that day he wrote back, and (as the nice guy he is) told me that he did not know the solution off the top of his head but he would look at it as soon as he had a couple of available hours. A few days later he had found a solution, and it turnes out a few things need to be done differently when running it outside of chiron. So this is basically what I want to share with this post :)

What you need to do is:

1) If your .rb files contain references like “app.xaml” it should be changed to app\app.xaml – in other words the references should be from the root of the solution and not from the app folder where the file is located.

2) Make the .xap file using the command script\chr /d:<projectpath> /z:<projectpath>\app.xap

3) In the index.html file where the .xap file is referenced find the like starting with <param name="initParams".
Change its value attribute to "start=app\app.rb,reportErrors=errorLocation".

And easy as 1-2-3, your site should work when running the index.html file.

Shortly put it really has been a fun project, and I really like the IronRuby and Silverlight combination, so it is definately not my last project where I will combine the two.


MongoDB – getting better for .NET

by DotNetNerd 6. March 2010 16:24

Since my last post Rob Connery has joined the team working on MongoDB, and he recently blogged about the latest additions he has made on github. I couldn’t resist taking a look at the latest changes, and even though there is still some way to go it is nice to see the improvements to the drivers for .NET.

My last sample is already depricated, so Ill shamelessly steal his sample, and modify it slightly just to see the new bits running with entities that I worked with last. So Ill recommend looking at the sample from the blogpost, since I’ll be using his session class.

First thing to notice from Robs sample is that I don’t have to think much about mapping classes to documents any longer. One thing that is already depricated even from Robs own sample is that it is now a requitement that the class has an identifier. So going with the simplest thing possible I added an ID integer.

using (var session=new Session()){
   session.Add(new Actor { ID = 1, Name = "Hans", Age = 40, Gender = Gender.Male });
   session.Add(new Actor { ID = 2, Name = "Eva", Age = 22, Gender = Gender.Female });

So comparing to Db4o, we are now closer to a similar experience. One of the things I’ll wait to look at, but I see as fairly importait is how either will handle Lazy<T> properties and other kinds of more advanced scenarios.

With the above objects saved the data can be accessed using a Linq query like so:

using (var session=new Session())
   var actors = session.Actors;
   foreach (var actor in actors.Where(a => a.Gender == Gender.Male))

The LINQ provider is still not too far along so I’ll leave it alone for now, but it is also one of the places where it will be interesting to compare e.g. db4o and MongoDB in the future.

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Ayende - the relational dragonslayer

by DotNetNerd 23. February 2010 18:31

Ayende, who most know to be one of the Guru's when talking about ORM's and by extention working with relationel databases came to a very interesting conclusion a couple of days ago when he received a phonecall. To parafrase his point in "Slaying relational dragons" in a few words, a very real and complex problem had one very simple and elegant solution - do not use a relational database. This acknowledgement is as a see it a strong incentive to take a look at what NOSQL solutions like document and object based databases has to offer. And his blogpost is something I would definitely recomment reading...


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Db4o – first look

by DotNetNerd 21. February 2010 13:12

As the next step in my recent adventures into NoSQL country I decided to take a look at db4o. Shortly put I hope it will give me more than the document based databases, like Mongo that I have also been taking out for a spin.

My interest in NoSQL has been kindled further than it already was because of blog posts from Rob Connery, who looked into practical approaches and posts on CodeBetter provokingly entitled Using an ORM is like kissing your sister. Basically what they are all saying is that it is very limiting that we always start out with a relational database without even considering this very very important architectural decision.

Object vs Document

Similar to the document based database, the big win is that there is no schema, and no need to map between objects and a relational model. Actually with document based databases you do map to key/value pairs, so it’s not the whole truth, but still simpler than mapping to a relational model.

Mapping can be expensive in two ways – because it takes time to write the code, and it does warrant a certain overhead. On top of that db4o as an object oriented database has a concept of relations between objects. This means that rich querying capabilities are build in and that it performs really well.

When comparing to MongoDB the big thing missing is that it basically works on a flat file out of the box. So you need something to handle concurrency and stuff like that. Rob Connery posted a nice sample of how this could be done, and its really quite straight forward, because db4o does provide all you need to do it.

The basic stuff

In the interest of simplicity I’ll just sample how to work with db4o directly. Also this will illustrate just how straight forward it really is. The first thing that brought a smile to my face was how little I had to do to save and query a bunch of objects.

using (IObjectContainer context = Db4oEmbedded.OpenFile(Server.MapPath("myDatabase.yap")))
    var empolyeeToSave = new Employee() { Name = "John", Card = new TaxCard() { Number = "12345678" } };

    IList<Employee> retrievedEmployees =
        context.Query<Employee>(employee => employee.Card.Number == "12345678");


As you can see it’s very straightforward stuff. Besides this type fo querying which takes a predicate, there is also a QueryByExample, which works as one would expect. Another nice thing is that all calls to the Store method make up a transaction, so there is a Rollback method available. When the context is disposed the convention is that Commit is called for you, so when you don’t need rollbacks you don’t have to think about it.

Indexing is also possible with db4o, and it is also very simple to do, so if for instance I would like to apply an index for the name property on my Employee I could do this.


Moving along

Some of the first things that I have heard people think about when I say object/document based database is how to handle versioning and querying. With querying in this case I mean how to enable a scenario similar to opening SQL Manager and writing some queries to take a look at the actual data.

The versioning part may take a little work, but there are methods to help with e.g. renaming directly baked in - and besides, it takes work no matter what kind of database your using. On top of that my thought is that both of these issues can be addressed with a dynamic language. My plan is to take a look at this at some point, and that it will fit nicely because my copy of IronRuby Unleashed should be on it’s way :)


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Who am I?

My name is Christian Holm Diget, and I work as an independent consultant, in Denmark, where I write code, give advice on architecture and help with training. On the side I get to do a bit of speaking and help with miscellaneous community events.

Some of my primary focus areas are code quality, programming languages and using new technologies to provide value.

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