Dog door lock/latch

Got this dog door to block my dogs from going upstairs. The built-in latch was too stiff and dumb so, I removed it. But then my dogs quickly learned how to open the door because it was held by only a weak return spring. So, I made this magnetic latch. There is a spring that holds it in a retracted position until the door is closed. When it is closed a pair of magnets easily overpower the spring and lock the latch.

I understand that there are many similar door designs and this particular latch won't fit most of them. This is just a generic idea with the Freecad source file included. You can adjust it to your needs.

Here is how it works:
https://www.youtube.com/watch?v=kn79l3Vr7XQ