Yes, the van driver should have looked more carefully (or more than once) and had his signal on. But also you were passing moving traffic on the right. You were in his blind spot when he checked his mirrors just before turning. Mini-vans have big blind spots, too.
Even though it was basically his fault, cars just WILL do the wrong thing, and you can bet they'll do it on a regular basis. It's up to us to try to keep ourselves out of dangerous traffic situations where they can get us.
I always get really nervous when I start going faster than traffic and am on their right near the curb- it's a situation I try to avoid because I know eventually someone will suddenly turn right into a driveway without signaling and without seeing me, or one of them will suddenly swing a passenger door open to let someone out or something. It's always something. At that point I start coasting and make a choice to either get IN the lane with the traffic or else I slow down to their speed so I can watch for the obstacle course to unfold. Sometimes in that situation I'll even get on the sidewalk if there are clearly no pedestrians around anywhere. Whatever keeps me safe.

I'm sure glad you didn't get more badly hurt! Good thing you weren't going really fast.