Scripting: Get object transformation for every render frame (depsgraph issue)

Whenever an animation is rendered, I want to extract the camera transformation matrix and save it to a file. My problem is that the transformation is not updated during render. This is a known issue and after some search I figured out that I have to use the depsgraph to retrieve the information. The problem is that neither render_pre nor render_post have the depsgraph argument.

So what is the correct way to retrieve object data in one of those application handlers? Am I supposed to register for depsgraph_update_post and store the information in a member until needed?