ASP.Net MVCExtensibility, scalability and testability

Andrew Locatelli Woodcock

Andrew Woodcock 15 years development experience, mostly Microsoft

technologies specializing in server-side development with C#, ASP.Net / ASP.Net MVC and SQL Server

Writing code with C# since 2004 For last 2 years have worked as a Lead Developer for

CitiBank in Dublin as a member of Citi’s UI Framework’s team, developing a common ASP.Net MVC and C# based UI framework to underpin Citi’s future banking websites around the globe

About Me

Brief intro to ASP.Net MVC, what it is and what it isn’t

The Model View Controller design pattern Why use ASP.Net MVC: extensibility,

scalability and testability ASP.Net MVC in action: the Fly by Night

Courier website, unit testing and custom view engines

About the presentation

Developed as an open-source compliment to ASP.Net WebForms

Gaining in popularity and now in version 3 Very logical and easy to use – most of the time! In comparison to WebForms, offers:

Full control over HTML and URLs Better scalability: no more View State! Better separation of concerns Extensibility Testability

Brief intro to ASP.Net MVC

Event-driven Stateful Tightly-coupled: data, business logic and

presentation are separated – you can even develop your own View Engine to drive presentation

WinForms for the Web! It does not have a complex event-driven page-lifecycle, it does not mix presentation and business logic in a form

ASP.Net MVC is NOT

The Model-View-Controller design pattern has been around since the late 1970s

Clear separation of concerns Model is data View is presentation of data Controller manages Model and View to

produce output but decouples data from its presentation

Model View Controller

Very easy to develop – most of the time! Logical and consistent – again, most of the time! Stateless: no more page life-cycle Highly testable: more so than ASP.Net WebForms

although some features are still difficult to mock: HttpRequest object for one (as opposed to HttpRequestBase)

Scalable: single round-trip per view, no ViewState Highly extensible: pretty much everything can be

customized

Why MVC?

Renders pure HTML, CSS and JavaScript Designed to REST principles Excellent AJAX support – supports JSON natively Like Ruby on Rails, ASP.Net MVC “favours convention over

configuration”: Controller names end in …Controller Controllers are placed in the Controllers folder, Models in the

Models folder and Views in the Views folder Controller ActionMethod names usually match the name of the View

they generate: Details method will return the Details view, etc. Views reside in known locations: Views / {controller} / {action}

although this can be changed in Routes

More MVC goodness

MVC supports multiple View Engines even in the same project: ASP.Net, Razor, Spark, Nhaml, etc.

Views can use any syntax that their View Engine understands

Views can be strongly-typed to a Model, allowing much of the view to be templated and automatically created

Different Views can use different View Engines View Engines can support new View syntax or use

existing syntax in new ways You can develop your own custom View Engine … as we

shall see …

There’s still more …

ASP.Net MVC is more readily unit testable than ASP.Net WebForms Controllers, Views and Models can all be unit tested reasonably

easily Separation of concerns aids unit testing – Models are POCO for

example MVCContrib TestHelper provides helper methods to setup

Controllers, etc. ready for testing – we’ll see this in action later Models are POCO – very easy to test MVC provides wrapper classes to better support mocking intrinsic

objects: HttpContextWrapper, HttpRequestWrapper, etc. Still not perfect though due mainly to hang-overs from ASP.Net

WebForms – very hard to mock the HttpRequest static class for example.

Testing, testing

Let’s get our hands dirty! Deep dive into MVC via the Fly by Night

Couriers website Hands-on MVC Some testing And some custom View Engine goodness …

Fly by Night Couriers

ASP.Net MVC 3: http://www.asp.net/mvc/mvc3 Moq mocking framework:

http://code.google.com/p/moq/ - no more record-replay!

MVCContrib TestHelper: http://mvccontrib.codeplex.com/releases/59313/download/198550 - easy initialization of Controllers and their intrinsic objects, etc.

Log4Net: http://logging.apache.org/log4net/ activePDF WebGrabber WBE: http://www.activepdf.com

Software used

This presentation and the code samples will be summarized on my blog over the next few weeks:

http://www.andrewlocatelliwoodcock.com

Second chance