在每个控制器操作之前/之后执行代码

Question

I have an ASP.NET MVC application for which I want to log events. I have already a Log class with all the tools I need, but I have to instantiate and to close it explicitly (because it opens files, so I can't depend on the GC). My actions would look like this:

public ActionResult MainMenu()
{
    CreateLog();

    // Do controller stuff
    Log(message);
    // Do more controller stuff

    CloseLog();
    return View(mModel);
}

Or I could use a using block, but it would be just a little less intrusive AND it would create troubles with exception handling. I've read about ActionFilters , which I could use to create and close my Log, but then I would have no way to access the Log object inside the method.

Do you have any suggestion? How could I avoid having to repeat the code?

Answer 1

If the other suggestions don't work or if you need to do things other than just logging also be aware that you can override the OnActionExecuting method (often in a base class for reuse).

// Custom controller.
public class CustomController : Controller
{
    protected override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        // Do whatever here...
    }
}

// Home controller.
public class HomeController : CustomController
{
    // Action methods here...
}

Answer 2

I would recommend you to push in a Logger (probably ILogger) object as a dependency to your controller. You can control the lifetime of this logger object by a DI container (Unity, for example) - and if neccessary you can define its lifetime as request scoped. The other benefit of this soution that your code will remain testable.

Answer 3

you can use modules because they both sit in a pipeline and can provide pre and post processing for the core execution of a request. BeginRequest / ActionExecuting and EndRequest / ResultExecuted. They both also provide authorization hooks.

http://msdn.microsoft.com/en-us/library/aa719858(v=vs.71).aspx