How to politely ask someone's name by SMS?

That's a good question. My personal opinion is: first of all, it should be different from person to person, because if your personality is the kind of straightforward person, you can ask directly, for example, if you don't mind, may I have your name? If not, because you know most of this stranger, you can ask him some recent developments, such as where are you now? What are you doing? How have you been recently? Some daily communication language to know who he is.