There has been a lot of buzz over the past few days about ASP.NET MVC allowing developers to create RESTful URLs.  This turned out to be very good timing since I was implementing RESTful URLs without first realizing it in MonoRail last week.

I had to give a business partner two links to our new online service, one for each screen mode the partner's web device supported: splitscreen and fullscreen.  This got me thinking about the URLs I was providing, since I was essentially etching the URL in stone; I wanted to make sure they looked professional and provided maximum flexibility in the future.  It also got me wondering if I couldn't add additional information into the URL; information that in the past I would have stuck in a cookie or in a session. 

At first I put this extra data in the session, but then I started thinking about: session time out, load balancing, SQL Server DB, and scalability. Cookies might be better, but then I thought how the browser on these devices immediately asks you if you want to store a cookie - bad first impression.  It seemed the answer was to use the querystring and pass state around from one page to the next on the querystring, but I hated the idea of passing around a few values on every single page request.  This seemed fragile and made every page URL ugly and long.

I already knew that you generally want to use directories, or resources, over querystring parameters for web search engine optimization, but then I realized that using resources instead of querystring parameters is also more organized and user friendly.  Here's an example of two URLs, one using a querystring, and the other using a REST style resource URL.

http://sneal.net/fullscreen/categories/category1/page1

http://sneal.net/categories.rails?screenMode=fullscreen&category=1&page=1

I think its pretty obvious that the first (REST style) URL is much better for several reasons:

• Easier to read, it's essentially just a directory path.
• Easy to remember, it avoids strange symbols and is shorter.
• Provides a nice structure to the data: categories -> 1st category -> 1st page.
• It's discoverable.  Its pretty obvious what you can type in to go to page2 etc.

Another benefit is that links into your web application aren't tied to a particular technology or platform.  I've already experienced this at GalleryPlayer when we wanted to change some static HTML content into dynamic ASP.NET pages - external URLs weren't just looking for a resource, but they were explicitly looking for a static HTML page.  If we had implemented REST style URLs from the very beginning using URL rewriting, any external links could have been using a technology agnostic URL instead of a specific one tied to static HTML.

For example, I can point people to http://sneal.net/blog/somepost, rather than http://sneal.net/blog/blog.aspx?post=somepost.  If later on I decided to switch from dasBlog to a ROR based blog engine running on Linux, I could do that without anyone being the wiser.  The blog.aspx link would be much more difficult to change the underlying technology to ROR since the link includes the resource 'blog' and the view implementation type, 'aspx'.

Lets not forget what URL stands for: Uniform Resource Locator. In the end the consumer of your data shouldn't really care how you produce the results, whether you're using ASP.NET, MonoRail, ROR, PHP, or JSP.  The only thing the consumer should care about is the data your service, or web page, is providing - and where to find it at.  With an MVC framework like MonoRail, ROR, or ASP.NET MVC, URL routing couldn't be easier.

As K Scott Allen said, "The [ASP.NET] MVC framework is, I believe, about putting control in the hands of a web developer. Control over the routing of HTTP requests to components. Control over selecting the view. Control over state management, and control over the outgoing HTML."  I couldn't agree more.  URL routing/rewriting gives you a flexible abstraction layer between your URLs and your resource implementations.

In my next post I hope to show how I avoided session state and cookies by using REST style URLs with MonoRail.

Here's a good reason not to use untyped datasets.  I was tasked with hiding a radio button on a webform depending on the SkuType of the product.  Unfortunately I have no idea if the web application, let alone the web service it uses for data access, returns the SkuType already.  The web service just returns a bunch of untyped datasets as raw strings.  To actually figure out what each web service call is returning I have to look at each sproc's SELECT statement.

If I had some hint in the code of what the expectations of the form of data, I could at least grep for SkuType.  As it is now I may be adding it to an existing sproc, thus unknowingly duplicating logic.  I guess my only alternative is to export out all sprocs to a script and then grep the script for SkuType.

I did a commit from my home PC tonight where I don't have CCTray installed.  I don't have it installed largely because I'm usually disconnected from work VPN and CCTray will just show up as a gray ball in my systray.

After committing my changes I felt pretty nervous because there were a lot of new files added to the project and I wasn't using VisualSVN which would normally make sure these get committed.  After checking my email and not seeing any commit mails from the SVN server - I got very nervous.  Did my commit go into a black hole?  Is SVN down, did the build server crap out, is email down?  Ah!

I finally figured out Outlook wasn't synchronizing my Checkins mail folder for whatever reason.  In a panic I went and installed CCTray, and found that my commit was just fine and SVN didn't send it into a black hole after all.

I didn't realize that working with a continuous integration server with almost instant feedback is so tightly integrated into everything I do development wise.  What really surprised me was how much I use commit emails.  I didn't like commit emails when I first started the practice (they were a manual affair then), but now that they get auto generated upon commit using CaptainHook and use the SVN commit description, I've grown to really like them.

Now I can sleep soundly knowing that my code is safe.

After using DisplayFusion for the past week at work I came home to use my PC and discovered that something was missing.  As it turns out I heavily use the "drag maximized window" feature of DisplayFusion at work, and probably won't ever use another OS/PC without this feature (assuming I have more than one monitor).  It almost seems like a bug that Vista doesn't natively support this feature out of the box.

In my previous post I assumed that I would need to explicitly load my child objects through my service and provide a finer grained service interface to support that model.  After digging through Udi Dahan's blog posts again I found a very relevant post about using a fetching strategy to specify how deep you want the object model to be for any specific request.  By being able to specify a fetching strategy in the consumer code I can return the proper size object graph without making my service interface chatty.

This does leak some of the service logic into the client code, but really I'm OK with that.  The alternative is to explicitly call each service method which I think is harder to maintain and makes the object model pretty difficult to use. 

After using Mule ESB at my last job I've found it kind of hard to go to plain old web services.  I really like the messaging paradigm and separation of concerns an ESB provides.  Now if I could just find the SVN repository for NServiceBus.

I downloaded the NHibernate VS2005 plugin and started to use it - its very similar to the Hibernate support built into Eclipse.  Unfortunately after playing around with it for about 20 minutes I realized my data model (in the DB) was complete poo and the plugin wasn't built to handle legacy databases, which I completely understand because that's where the majority of NHibernate's complexity lies IMO.

I really don't want the crappy data model to leak into my object model - even though it would be super easy and fast to "whip it out" using the plugin or another code generator.  I'm kind of stuck on what to do right now.  Part of the problem is I'm not sure I have time to "do it right." I have a hard deadline looming from a 3rd party that can't budge.

I think I may start out modeling my object model from scratch, which isn't too bad with Re# installed.  Then from there start manually mapping some of this stuff to the existing sprocs or creating some new views.  I also have the problem that this will all be serialized and sent over a web service and/or NServiceBus, so I'm not sure how to handle relationships.  Probably in most cases I'll just have IDs of the FKs and then explicitly make another fetch from the service since lazy loading is pretty much out of the question.

I opened up another tab to Udi Dahan's blog, at which point my PC came to a screeching halt.  After finally getting the task manager open I noticed FireFox was using 1.5GB of RAM.  Wow!  IE never uses that much memory - in fact IE usually crashes well before it ever gets that much memory consumed.  Here's a look at my memory usage after I killed FireFox, note the huge drop in the Physical Memory Usage History (blue line).

I just checked off my last item (fast PC) from the "Programmer's Bill or Rights."  Compared to my last job that's a 66% improvement.

Setting up a new Windows development machine is a pain.  In fact it's more work than setting up a Linux development machine.  In Linux the package manager for the OS, the Rails package manager, and/or the Eclipse update manager handles most of this for me.  In Windows I'm forced to install things individually using separate installers.  Here's the minimum I had to install on my brand new Windows Vista box to get a decent development environment:

• Visual Studio 2005
• VS 2005 SP1
• VS 2005 SP1 patch for Vista
• Windows Vista SDK
• WCF for VS 2005
• .NET 1.1 Runtime (yes, I still have a project that compiles .NET 1.1)
• ReSharper 3 for C#
• SVN
• TortoiseSVN
• VisualSVN

That's just to get my machine compiling our code, that doesn't even include the numerous other tools I need to be productive like Paint.NET or MS Office.  All in all, I had to install around 30 applications yesterday!  No wonder I've been dragging my feet on getting a new system for the past month.  The good news is, I'm now done and this new 3GHz dual core system with 3GB or RAM freakin' rocks compared to my old Dell Dimension 4600.

Scott Bellware brought up SmartBear Code Collaborator code review tool as a way to annotate code on the ALT.NET mailing list today.  It looks really interesting to me since my entire team works remotely and facilitating code review is pretty difficult.  We've used NetMeeting in the past, but I would like something that promotes a more organic code review which naturally happens when co-located.

The really neat thing is that integrates tightly with source control systems such as Perforce's Windows client so that you can initiate a code review of a particular changelist before checkin.  I didn't see any mention about SVN integration...