How should you repair a wing-back chair leg that snapped off?

I had this exact same thing happen. What I did. I removed the staples and tacks on the underside of the chair half way down the side and front of the chair then I rolled up the upholstery taking care not to tear it. I removed the leg from the chair. (A rear leg broken would be a completely different repair.) The leg is attached to the side stile and front board with 1 1/2" long 1/2" dowels. I had to work at it a little to keep from breaking it more. I then removed the dowels from the leg and boards. The leg can now be reinforced and glued back together if that is what broke. I usually use small short dowels and centering guides to drill and reinforce legs. Glue up and clamp the pieces together. On my wing-back the side stile actually split so i reinforced it with dowels drilled through the sides and glued them in with glue in the split as well, then i clamped it up. After it dried I drilled the dowel holes 2 inches deeper to get purchase in more solid wood and glued new 4" long dowels in. I then reinstalled the leg with new dowels and glue and clamped it up. After this dried I rolled the upholstery back down and stapled and tacked it back into place.