Showing posts from February, 2008

Custom config sections

The website I am writing will sell some software I have already written. In addition it will sell "Collateral", which is basically support files for the software. The software itself will only run if it finds a license, which is an RSA signed binary file containing information such as the email address of the licensee. In addition some kinds of collateral will also be RSA signed with the licensee’s email address so that it will only work for that user, but not all collateral types are signed, for example a Character is a custom file format and is signed but a WAV file will not be signed. So this website needs to sell software + provide a license. It also needs to sell collateral, some of which will require signing and some of which will not. Software and Collateral are both types of Product, and you can buy a Product. The problem is how should I deal with the 3 different types of licensing (license file, signed binary, no license)? In addition to this should I really cr

All users

Yesterday I needed my app to read and write data from a folder to which all users have access. Having the data in the current user's data folder was unacceptible as this would have resulted in duplicate data storages, the MSI installer even generates a compiler warning telling me I shouldn’t use this folder! So I went for Environment.GetFolderPath(SpecialFolder.CommonApplicationData); This seemed to work fine until I tested on Vista, at which point my app would "stop responding" and quit. With a bit of investigation I discovered that CommonApplicationData maps to c:\ProgramData on Vista, which to me looked good until I tried creating a read/write FileStream in that path and received an access denied exception. So, where was I supposed to store my data? Checking each of the values in the SpecialFolder enum I was surprised to see that there doesn&#8217't seem to be a suitable value. So, I reflected over Environment.GetFolderPath and copied the code. I then s

Embedded Firebird, error trying to write to file

This error has been really annoying me tonight! I have an app that uses Embedded Firebird for its DB so that I don't need to install a DB server. On Vista my app throws an exception "Error trying to write to file (the correct path here)". I recreated the DB on my development machine (XP) and tried running it, it should work, it has for months, but it didn't! The same error too! For the life of me I couldn't work out why it would suddenly stop working on both machines, what did they have in common? I uninstalled stuff, reinstalled it, etc, no joy. The answer on my XP box was simple. I used the local server to create the GDB file + generate my DB structure using ECO. What I hadn't thought of was the fact that the firebird server then holds a file handle open on that GDB file in case I want to use it again. Embedded firebird needs an exclusive lock on the file so this was the problem on my XP box. I wish the error had read something like "Erro

Test driven ECO

Here are my latest revelations :-) 01 Instead of having to mock IEcoServiceProvider and IOclPsService in order to avoid DB access simply use PersistenceMapperMemory. This way I can create the objects I want, UpdateDatabase, and then run my tests. It’s much easier to read, and more importantly less typing. 02 My page controllers no longer use an EcoSpace. Instead the code always uses a ServiceProvider property of type IEcoServiceProvider. When I want to test my controller I create an instance and set its ServiceProvider property. Now whenever the controller needs to do anything it will go through the ServiceProvider I specified. This is beneficial for a number of reasons. Firstly it means that I can create an EcoSpace in my test and set its PersistenceMapper to PersistenceMapperMemory before activating it. Secondly I can also opt to pass a mocked IEcoServiceProvider which either returns the real service requested or returns a mocked one. An example of this is that I validat

ECO, should we mock it?

I watched a video on Rhino Mocks yesterday. What a great framework! Obviously I wanted to know if I could use this with ECO so I thought I'd give it a try. In my website's AccountController there is a method like so public void AttemptLogin(string emailAddress, string password, string redirectUrl) { } Now I could just go ahead and write some OCL to find the user, but instead of doing this I really want to separate the code a bit. So I created a class public class UserRepository {   private readonly IEcoServiceProvider ServiceProvider;   public UserRepository(IEcoServiceProvider serviceProvider)   {     ServiceProvider = serviceProvider;   }   public User GetByEmailAddressAndPassword(string emailAddress, string password)   {     string searchEmail = BusinessClassesHelper.EscapeOcl(emailAddress);     string criteria = string.Format("->select(emailAddress.sqlLikeCaseInsensitive('{0}'))", searchEmail);     return BusinessClassesHelper.SelectFirstObjec

Unit testing MonoRail controllers

I spent yesterday finishing off (mostly) my business model, then the end of yesterday + today writing test cases for those classes. Everything was going great, I found at least 3 errors in my code that I hadn’t realised was there and also realised there were a few more things I needed. Then it was time to start testing the controllers in my MonoRail site. What a disaster! Attempt 1: [Test] public void AdminOnly_Home() {   AdminController controller = new AdminController();   controller.Home();   Assert.IsTrue(Controller.Response.WasRedirected, "Should have been redirected"); } The problem with this was pretty obvious, Controller doesn’t have a Response etc set up. So along came attempt 2: [Test] public void AdminOnly_Home() {   AdminController controller = new AdminController();   PrepareController(controller);   controller.Home();   Assert.IsTrue(Controller.Response.WasRedirected, "Should have been redirected"); } Now the controller is set up with mock ob


I have a model like so Product 1----* ProductVersion ProductVersion 1----* ProductEdition ProductVersion can been in one of two states: UnderDevelopment / Released ProductEdition has a DownloadUrl:string attribute which is only required if self.version.status = #Released The validation for ProductEdition works perfectly, I cannot leave the DownloadUrl blank if the ProductVersion has already been released. Unfortunately when I already have a number of ProductEdition instances with no DownloadUrl and then make my Productversion live the editions are not validated because they are not dirty. So I needed some way to ensure that when ProductVersion is validated all related ProductEdition instances are also validated. Step 01: Add a way to allow ProductVersion to identify other objects to be validated. In the business classes project I added the following interface. public interface IValidationExtender {   IEnumerable GetConstraintedObjects(); } My ProductVersion can do this


The whole idea of having a controller and a view is so that the view renders only exactly what it is given, and the controller is able to give it whatever data it likes from wherever it needs to obtain it. After working with ECO and Monorail for a while it has been a real pleasure, but I am starting to think that maybe exposing ECO objects directly to the view is not the right approach. If for example I put an Employee into the PropertyBag the view can easily display $Employee.Salary. This might not be a problem when you develop both the controllers and the view but in my case someone else will ultimately create the views. Do I really want them to be able to have access to this information? In addition, what if the view engine they use has a scripting language that is able to set values? Setting $Employee will merely set the PropertyBag["Employee"] value, but setting $Employee.Salary could see a certain view developer buying a new car next month. I am very tempted to c

Your bug is my bug

I recently released an update to some software and a bug slipped through the net. It introduced some odd behaviour with a control named SmartGrid. After some testing I was able to determine that it wasn't my fault and that I could reproduce a bug in SmartGrid. I hate bugs in other people's source code, I can't fix it, I am at their complete mercy. Thankfully the Resco support was amazing! I posted on their forums and immediately someone sent me instructions on where to send my project. The next morning I was disappointed to see an email saying that the project worked fine. I posted again and almost immediately someone had offered to chat on skype. We did that for a while, both confused by the problem. We then went on to use Remote Assistance so that he could observe my bug which he wasn't experiencing. In the end the problem was very confusing. I had Version A of the DLL in which the error occurred. I upgraded to the latest version (B) and it still occurred.

Converting a recurring decimal to a fraction

For a couple of hours a week I am doing a beginner's level maths course. The topic today was converting recurring decimals into fractions. For example (the [] are the repeating digits 0.[6]  1x = 0.[6] 10x = 6.[6] 9x = 10x - 1x 9x = 6.[6] - 0.[6] = 6 Therefore the answer is 6/9, or 2/3 When it got to numbers like 0.12[34] (ie 0.12343434343434.....) the lesson was really complicated, but I came up with a more simple approach, so here it is if ever you need it. My first observation was that we need a large number and a small number. So let's start with the 10x we used above  1x = 0.12[34] 10x = 1.2[34] therefore 9x = 10x - 1x which is  1.2[34] -0.12[34] This is going to give us 1.1(something) My second observation is that fractions cannot have decimal values in them. In order to get rid of the fraction we need the big number to have the exact same fraction as the small number. e.g.  B.[34] -S.[34] =X.[00] So our small number needs to end with [34]. Give


Implementing HTML maxlength was a bit of a pain. Not to write the helpers though, that was easy.... $EcoModelHelper.AttributeLength($Product, "ID") But when it came to specifying that in the <input> it was too much work! This is how it is done statically... $FormHelper.TextFieldValue("Product.ID", $Product.ID, "%{maxlength='32'}") Now I had to replace the static 32 with the EcoModelHelper code. #set ($ProductIDLength = $EcoModelHelper.AttributeLength($Product, "ID")) $FormHelper.TextFieldValue("Product.ID", $Product.ID, "%{maxlength='$ProductIDLength'}") This was starting to look like too much typing! So instead I have decided to add new methods to the EcoFormHelper. Here is the first: $EcoFormHelper.ObjectTextField("Product.ID", $Product, "ID") This will output something like this <input type="text" id="Product_ID" name="Product.ID"

EcoRail validation

Here is yesterday's update. I wanted a way to validate the user input. Seeing as there are constraints in the model to me this was the obvious approach to take. The HTML in my main layout (MasterPage) was changed like so <body>   #if ($Errors && $Errors.Count > 0)     <ul class="errors">       #foreach ($currentError in $Errors)         <li>$currentError</li>       #end     </ul>   #end   $childContent </body> This outputs all errors passed in PropertyBag["Errors"] or in my case I used Flash["Errors"]. To validate my product input I changed my controller like so: [AllowEcoSpaceDeactivateDirty(true)] public void Modify([EcoDataBind("Product", Allow = "ID,Name", NoObjectIdAction = ObjectIdAction.CreateNewInstance)]Product product) {   PropertyBag["Product"] = product;   IList<string> errors = GetErrorsForAllDirtyObjects();   if (errors.Count > 0)     Flash[

Changing the URL structure

I wanted the following URL structure in my website but the default url mapping in MonoRail would translate this as[controller]/[action]/[id] So it would expect to find this public class ProductController {   public void MyProductName(string id)   {   } } whereas what I actually want is public class ProductController {   public void WhatsNew(string productName)   {   } } Open Web.Config Locate the monorail node Locate the routing child node Now add a new <rule> to the top of the list: <rule> <pattern>/(product)/(\w+)/(\w+)</pattern> <replace><![CDATA[ /product/$3.rails?productName=$2]]></replace> </rule> As this is at the top of the list it will have the highest priority. If the URL matches /product it will remap the url From: To: withou

ECO docs progress

I'm currently in the process of migrating the QuickStart series from BDS over to VS and recreating the accompanying source code. There's quite a lot of information in those articles, I hadn't realised how much I had written! Well, the transcription is going quite well. So far I have made it as far as article number 5. This one is going a bit slower because it is also a translation from VCL .NET to WinForms.

Inversion of control

As you may already know I am writing a website. I've chosen to use MonoRail for the web part and ECO for the persistence. Today has been great fun! I have modified the Castle.MonoRail.EcoSupport library with the following enhancements. You can now specify a [DefaultEcoSpaceType(typeof(MyEcoSpace))] on either the class or method. On the EcoDataBind reflection attribute you can now specify as little as [EcoDataBind("Product")] on your method parameter, this will use the specified DefaultEcoSpaceType specified, or throw an exception if no default was specified. This lets me write code like this [AllowEcoSpaceDeactivateDirty(true)] [UseEcoSpacePool(false)] [UseEcoSpaceSession(EcoSpaceStrategyHandler.SessionStateMode.Never)] public class ProductAdminController : BaseController {   public void Create()   {     PropertyBag["Product"] = new Product(GetEcoSpace<MyWebSiteEcoSpace>());     RenderView("Modify");   } } I can now easily create actions Crea