python: Better error checking for events from python

[rm5248]

Use a context manager when locking in python to ensure that if an exception is thrown, the lock will be released.

Add some basic error checking to the submit_event function to make sure that card read events have the correct data set.

fixes: #267

[Copilot]

Pull request overview

This PR improves error handling and thread safety in the Python OSDP peripheral device implementation. The changes use context managers for lock management to ensure locks are released even when exceptions occur, and add validation for card read events to catch malformed event data early.

Key changes:

• Replaced manual lock.acquire()/lock.release() calls with context manager pattern (with lock:) for exception safety
• Added input validation to submit_event() to verify event structure and required fields for card read events
• Imported Event and CardFormat constants to support the new validation logic

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[Copilot]

The membership test should use the more idiomatic Python syntax 'event' not in event instead of not 'event' in event. While both are functionally equivalent, the former is the preferred style according to PEP 8.

Suggested change

	if not 'event' in event:
	if 'event' not in event:

[Copilot]

The code accesses event['format'] before validating that the 'format' key exists in the event dictionary. This will raise a KeyError if the 'format' key is missing. The validation should first check that all expected keys exist before attempting to access any of them, or should check for the 'format' key existence before accessing it on line 76.

Suggested change

	expected_keys = ["reader_no", "format", "direction", "data"]
	if event['format'] != CardFormat.ASCII:
	expected_keys.append("length")
	if not all(key in event for key in expected_keys):
	raise TypeError("cardread event missing expected key")
	# Base required keys for all CardRead events
	expected_keys = ["reader_no", "format", "direction", "data"]
	if not all(key in event for key in expected_keys):
	raise TypeError("cardread event missing expected key")
	# At this point, 'format' is guaranteed to exist
	if event["format"] != CardFormat.ASCII and "length" not in event:
	raise TypeError("cardread event missing expected key: 'length'")

[Copilot]

The error message does not specify which key is missing from the cardread event, making it difficult for users to debug the issue. Consider providing a more specific error message that indicates which expected key is missing, such as including the list of expected keys and the keys that are actually present.

Suggested change

	raise TypeError("cardread event missing expected key")
	missing_keys = [key for key in expected_keys if key not in event]
	present_keys = list(event.keys())
	raise TypeError(
	"cardread event missing expected key(s): "
	f"{missing_keys}; expected keys: {expected_keys}; present keys: {present_keys}"
	)

[sidcha]

@rm5248 Please ignore the AI review, I'm just trying it out.