Dispose method in web api 2 web service

Question

I am coding an MVC 5 internet application with a web api 2 web service. Do I need a dispose method for the DbContext class in a web service? It is not there as default.

Ignace

What would you do if you did need such a method? Were you planning to rewrite the DbContext class? – Kef

Hi , Check this #20837337, It might be useful for you. – Rhoden

@JohnSaunders: My DbContext class already has the dispose method, I am wondering if I need to add the dispose method to the web api controller. – Ignace

If your web api controller class holds an instance of the DbContext class (or any other IDisposable class), then yes, you need the Web API controller to implement IDisposable. If it does not hold any instances of an IDisposable-implementing class, then you don't need to implement IDisposable. – Kef

Answer 1

Actually, System.Web.Http.ApiController already implements IDisposable:

// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the  project root for license information.
// ...
public abstract class ApiController : IHttpController, IDisposable
{
// ...
    #region IDisposable

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
    }

    #endregion IDisposable
}

So, if your controller holds a DbContext, do the following:

public class ValuesController : ApiController
{
    private Model1Container _model1 = new Model1Container();

    protected override void Dispose(bool disposing)
    {
        if (disposing)
        {
            if (_model1 != null)
            {
                _model1.Dispose();
            }
        }
        base.Dispose(disposing);
    }
}

Kef

This was exactly what I was looking for. I already had an implemented code similar as yours in MCV, didn't know the same was for Web API – Mortar

Answer 2

In Web Api 2, you can register a component for disposal when the request goes out of scope. The method is called "RegisterForDispose" and it's part of the Request. The component being disposed must implement IDisposable.

The best approach is to create your own extension method as below...

       public static T RegisterForDispose<T>(this T toDispose, HttpRequestMessage request) where T : IDisposable
   {
       request.RegisterForDispose(toDispose); //register object for disposal when request is complete
      return toDispose; //return the object
   }

Now (in your api controller) you can register objects you want to dispose when request finalize...

    var myContext = new myDbContext().RegisterForDispose(Request);

Links... https://www.strathweb.com/2015/08/disposing-resources-at-the-end-of-web-api-request/

Cagliostro