My favorite Web Application Architecture
This is my first blogpost and I thought I should start writing about the web application architecture i normally choose these days, –if I am allowed by the client to refactor or start from scratch. Hopefully more blogposts will come out of this.
The first thing I do is splitting the Web Application in a html part and a JSON REST API part. Typically the Visual Studio folder structure looks like this:
- WebApplication1.WebSite
- WebApplication1.RestApi
HTML
I use the Razor viewengine in combination with Knockout.js to write the databinding and other than this the HTML is mostly consisting of a bunch of DIVs and script elements with jquery $.get or $.post’s. Normally I am that lucky in projects that I do not have to care about the “colors and stuff”, there is normally another guy taking care of the CSS. My main focus is therefore to get the databinding right and have a nice and clean architecture “downwards”.
REST API
I design the REST API service methods with the view in mind. So instead of having a super-generic method that works for “all web pages” I rather have several specific ones. I want to have as little logic in the client side as possible. I can then design my viewmodel-classes to consist of just the data needed, both translated and formated the way i want.
CQRS style: When working with the REST API I like to split the GET and POSTs as done in CQRS.
- The GET-methods are fetching data from the database through a simple ORM like for example: EF, Dapper, Massive or Simple.Data. If working with a documentdatabase as for example RAVENDB the queries will go directly to its DocumentSession.
- The POST-methods will have the business logic and sometimes be long running processes. A reliable service bus as nServiceBus is therefore to prefer. When working with long running and asynchronous processes special care must be taken when designing the UserInterface (HMTL pages). They can normally not be designed as done when working with request-response-based applications.
Environment:
If the team developers are writing tests and the application above is on GitHub using TeamCity with Continuous Deployment, then my day is perfect!
jQuery validation not working in IE7 and IE8
When you create a new ASP.NET MVC 3 Project in Visual studio, your script folder will by default contain among others:
jquery-1.5.1.min.js
jquery.validate.min.js (which is version 1.8.0)
One of the first things you might want to do is update the jquery version to the latest version, which today is version 1.7.1
After doing this, your client side validation will stop working in Internet Explorer 7 and Internet Explorer 8.
This is because the jquery.validate version is not compatible with jquery versions > 1.6. The solutions is simple, you need to update your version of jquery.validate as well. You can find the current version 1.9 from Microsoft’s CDN or the latest version from GitHub here:
Microsoft Ajax CDN: http://ajax.aspnetcdn.com/ajax/jquery.validate/1.9/jquery.validate.min.js
GitHub Jquery Validation: https://github.com/jzaefferer/jquery-validation/downloads
Remember that you can always find the latest javascript library in Microsofts CDN, see the complete list of available libraries here: http://www.asp.net/ajaxlibrary/cdn.ashx
ASP.NET MVC with Cleaner Data Annotations
While using data annotations with localization in your MVC model, you may end up with some untidy looking code like in this example, where all we do is adding display information and validation:
1: public class Character {
2: [Display(Name="Character_FirstName", ResourceType=typeof(ClassLib1.Resources))]
3: [Required(ErrorMessageResourceType=typeof(ClassLib1.Resources),
4: ErrorMessageResourceName="Character_FirstName_Required")]
5: [StringLength(50, ErrorMessageResourceType = typeof(ClassLib1.Resources),
6: ErrorMessageResourceName = "Character_FirstName_StringLength")]
7: public string FirstName { get; set; }
8:
9: [Display(Name="Character_LastName", ResourceType=typeof(ClassLib1.Resources))]
10: [Required(ErrorMessageResourceType=typeof(ClassLib1.Resources),
11: ErrorMessageResourceName="Character_LastName_Required")]
12: [StringLength(50, ErrorMessageResourceType = typeof(ClassLib1.Resources),
13: ErrorMessageResourceName = "Character_LastName_StringLength")]
14: public string LastName { get; set; }
15: }
While working on a project I found a NuGet Package which helped me to clean up this “mess”.
The extension is created by Phil Haack and derives from the DataAnnotationsModelMetadataProvider. The beauty of this extension is that you can set up a default resource type in Global.asax like this:
1: ModelMetadataProviders.Current = new ConventionalModelMetadataProvider(
2: requireConventionAttribute: false,
3: defaultResourceType: typeof(MyResources.Resource)
4: );
Note that the first argument, requireConventionAttribute, determines whether the conventions only apply to classes with the MetadataConventionsAttribute applied.
After you have configured the default resource type, it is no longer necessary to specify the ResourceType or ErrorMessageResourceType attributes. Also, the custom metadata provider looks up the resource key named the same as your property so that you are no longer required to specifying Display(Name=”FirstName”) as long as you match the property name and the resource name.
The same goes for validation attributes where you can use a resource key of {PropertyName}_{Attributename}, for example, to locate the error message for a RequiredAttribute, the provider finds the resource key FirstName_Required.
The “messy” data annotation code from above could with this extension look something like the code below, and still give the same result as long as you have the resources “FirstName” and “LastName” in your default ResourceType:
1: public class Character {
2: [Required]
3: [StringLength(50)]
4: public string FirstName {get; set;}
5:
6: [Required]
7: [StringLength(50)]
8: public string LastName {get; set;}
9: }
Hello good lookin’ !
You could of course provide some metadata, the metadata that you don’t supply is inferred based on the conventions. You may also like that if a value for a given resource is not found, the code falls back to using the property name as the label, but splits it using Pascal/Camel casing as a guide. Therefore in this case, the label is “First Name” and “Last Name”.
ASP.NET MVC 3 Beta
_thumb.png?cdn_id=2010-09-09-001 "ASP.NET MVC 3")
ASP.NET MVC 3 Beta was released earlier this month. I tried to install it through the Web Platform Installer, but got the message: "The product you are trying to install is not supported on your operating system". I run Windows 7 32 bit and that is of course supported. The solution is to download the installation files from this web site.
If you encounter the message: "This product requires Microsoft ASP.NET Web Pages 1.0. Please install the missing component, then try to install this product again." when running the MVC 3 beta installation, go back to the same website and download the AspNetWebPages.msi file and install this first.
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