How to tell the controller what view to call?

Question

I have a virtual function that is called handlePathChange() in my Controller class.
It checks the current URL and should dispatch the right view for it.
Here's the code I have so far:

void Controller::handlePathChange()
{
    if ( app->internalPathMatches(basePath) )
    {
        string path = app->internalPathNextPart(basePath);

        if ( path.empty() ) // If it's empty it is known that the index of the controller should show up
            index();
        // else if ( path == ?? ) each controller has it's own routes
        //   call_some_unknown_function();
    }
}

How can I generalize this?
I was thinking about two options:

1. Call a pure virtual function called dispatch() that will match the right path to the right function in the derived class. This solution violates DRY as basically you will write the same code over and over again.
2. Create a hash maps of std::function but then if a part of the url is a parameter then the view won't be found. So that option isn't good enough.

Any ideas?

Answer 1

I realize your post uses a c++ example, but if you don't mind reading some c#, this article by Scott Guthrie is a great overview of how the ASP.NET MVC framework implements its routing:

http://weblogs.asp.net/scottgu/archive/2007/12/03/asp-net-mvc-framework-part-2-url-routing.aspx

I think you will find that article very helpful. In an overly simplified sort-of-way, it is similar to your option #2, yet it always checks for a parameter. If the parameter is not provided, it uses the same routing rule, but provides a "default" value and sends the request to the correct view. That strategy avoids the problem you mention where you can't find the appropriate view if the parameter is specified.

Hope this helps.