Question

I have a class Logger with a number of static methods for various user activity logging. Something like:

public static class Logger
{
    public static void FileDownload(int fileId, int userId) 
    {
        // Do stuff
    }

    // ... and a number of similar additional methods
}

So what I’ve come to now is that I want to ignore logging the activity for users of a certain role.

The idea I had, to avoid rewriting a lot of code and for the purpose of DRY, was to implement a custom attribute that I can use on the Logger class, which will, for every method call, verify if the user is in a certain role, and in that case I want to ignore the method call altogether.

The problem I can’t wrap my head around is how to intercept and abort the method-call within my attribute.

Is it possible, or is there some other more efficient way to intercept a method call and ignore it if a certain condition is true?

Answer 1

A way to do this efficiently and DRY is to change those methods from static to instance methods, then inherit from class Logger and override its methods to do nothing.

Your Logger class will now look like this:

public class Logger
{
    public virtual void FileDownload(int fileId, int userId) 
    {
        // Do stuff
    }
    // ... and a number of similar additional methods
}

And the subclass will look like this:

public class IdleLogger : Logger
{
    public override void FileDownload(int fileId, int userId) 
    {
        // Do NOTHING
    }
    // ... and a number of similar additional methods
}

Then you can say:

var myLogger =  IsUserInNoLoggingRole  ? new IdleLogger() : new Logger();

…and you are done! Simple, efficient, DRY and elegant.