FYI, I’m working on my first MVC web application using MVC 3 and Razor with C#, and .NET3.5/4.0, and I’m looking for the “best pratice” approach for using existing web services in an MVC 3 application. From what I have figured out so far it looks like all I need to do is the following. Include a reference to the existing web service in the MVC project, create a Model for the data I desire to use in the application, create a Controller that makes the web service call that then fills an object created from the Model (reading about AutoMapper to see how this helps in that process), and then create a View to display the data that was translated into the MVC view model.
The part that I’m having questions about is what is the best way to retrieve and create/update the data from the web service. Maybe I’m over complicating this but it seems like I’m missing something.
Do I need to create a “Domain Model” that maps to the data retrieved from the web service and then create “View Models” that map to the domain model, and then use the View Models within the MVC 3 application?
Basically I’m looking for input on how best to use existing web services as my data access layer.
On your data access layer you would open the connection, get the raw data and then close it. Identically to how you would get data from your database. You would then convert this raw data to your business layer (domain model) via a data adapter. Then any top level applications, such as your MVC3 website, will convert this domain model into an approriate view model, along with any other data for rendering, again through a data adapter.
The main argument for doing it this way is that the service is now accessible to any top tier application that requires it. It is also makes logical sense to put any sort of data retrieval methods in your data access layer, since that’s logically what the data access layer is designed to do.
There is always the temptation to simply access the service from your controller, but separation of concerns might suggest this is a bad way to structure your code. You should encapsulate the service as a domain/business layer service for your applications.
So in short, you don’t need to, but best practice suggests you should. It can feel tedious sometimes when there is little or no conversion between layers, but it often helps to stay consistent.