I am going to try this after finding an old clutch bag with an actual old measuring tape used for the closure. It still worked great too.
Cut a metal measuring tape (The wide yellow Stanley tape is good) to fit around the purse and sew it in like elastic. That will make a snap shut opening. Easier then sewing in a zipper. I don't like sewing zippers.
I better explain more. Don't sew through the metal but encase it like a waistband.