How to get a snapshot of a Messages thread?

I'd like to snapshot an entire Messages thread to archive it only using the iOS device. As I understand it, there is no public (or otherwise!) means to grab the contents in some structured manner (ie, text, URLs, images, who is the sender, who is the receiver).


The only solution I've thought of is to ask the user to make a series of screen shots, then provide them to me, and I'd use image stitching to construct what appears to be a very tall image with the whole converstation.


Obviously, if the user screws up and doesn't leave a bit of top and bottom to match it won't work and I'd have to ask them to do it again.,


This sure seems like a tangled approach to achieve the goal that I suppose some reasonable number of Messages uses would like, but the only one I can think of.


Did I miss some obvious other solution?


David