basler
The Camera Object Does not Follow the RAII Principle
It is an amazingly helpful library, but I noticed the pypylon.pylon.InstantCamera class does not follow the RAII principle to open and close a camera. Instead, it leaves the acquisition (and eventual release) of the camera to developer judgement. I am curious if the maintainers had their reason for making this choice, and what possible scenarios are aided by this.
Nonetheless, I thought some developers can benefit from this class that I developed as a context manager wrapper around the existing InstantCamera, that can replace the parent class respecting the Liskov substitution principle and can be used within a with block.
class CameraContext(py.InstantCamera):
"""This class is to respect the RAII principle of managing the camera resource."""
def __enter__(self):
"""Acquire the camera."""
self.Open()
def __exit__(self, exc_type, exc_val, exc_tb):
"""Release the camera."""
self.Close()
I can also add the methods to the existing class, if the maintainers are accepting contributions from the community. Kindly let me know the contributing guidelines for that.
Thanks for your feedback.
You can always create a pull request to our project.
Looking at your proposal, I thought about embedding this context manager into the InstantCamera class itself ( which is already extended in a lot of places compared to the C++ functionality )
Only tricky thing might be, to check if this covers all paths to create/attach an instant camera
Only tricky thing might be, to check if this covers all paths to create/attach an instant camera
One thing to keep in mind when thinking about this: There are rare cases where you need an intermediate step between creating an InstantCamera and opening it. In my - admittedly quite unusual - work, I occasionally have to register a different configuration than the default (using RegisterConfiguration).
