Locking by string. Is this safe/sane?

Question

I need to lock a section of code by string. Of course the following code is hideously unsafe:

lock(\"http://someurl\")
{
    //bla
}

So I\'

Answer 1

Here is a very simple, elegant and correct solution for .NET 4 using ConcurrentDictionary adapted from this question.

public static class StringLocker
{
    private static readonly ConcurrentDictionary _locks = new ConcurrentDictionary();

    public static void DoAction(string s, Action action)
    {
        lock(_locks.GetOrAdd(s, new object()))
        {
            action();
        }
    }
}

You can use this like so:

StringLocker.DoAction("http://someurl", () =>
{
    ...
});