Added Robust JSON Decoding

[jannick-schroeer]

Proposed change(s)

handle_syscommand uses a un-robust JSON decoding implementation. This leads to errors when using it in combination with Unity ROS Teleoperation.

[default_server_endpoint-1] json.decoder.JSONDecodeError: Expecting ',' delimiter: line 1 column 58 (char 57)
[default_server_endpoint-1] [INFO] [1761210822.634175002] [UnityEndpoint]: Connection from 127.0.0.1
[default_server_endpoint-1] [INFO] [1761210822.635462761] [UnityEndpoint]: Disconnected from 127.0.0.1
[default_server_endpoint-1] Exception in thread Thread-36:
[default_server_endpoint-1] Traceback (most recent call last):
[default_server_endpoint-1]   File "/usr/lib/python3.12/threading.py", line 1073, in _bootstrap_inner
[default_server_endpoint-1]     self.run()
[default_server_endpoint-1]   File "/home/jannick/ros-ws/build/ros_tcp_endpoint/ros_tcp_endpoint/client.py", line 213, in run
[default_server_endpoint-1]     self.tcp_server.handle_syscommand(destination, data)
[default_server_endpoint-1]   File "/home/jannick/ros-ws/build/ros_tcp_endpoint/ros_tcp_endpoint/server.py", line 126, in handle_syscommand
[default_server_endpoint-1]     params = json.loads(message_json)
[default_server_endpoint-1]              ^^^^^^^^^^^^^^^^^^^^^^^^
[default_server_endpoint-1]   File "/usr/lib/python3.12/json/__init__.py", line 346, in loads
[default_server_endpoint-1]     return _default_decoder.decode(s)
[default_server_endpoint-1]            ^^^^^^^^^^^^^^^^^^^^^^^^^^
[default_server_endpoint-1]   File "/usr/lib/python3.12/json/decoder.py", line 337, in decode
[default_server_endpoint-1]     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
[default_server_endpoint-1]                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[default_server_endpoint-1]   File "/usr/lib/python3.12/json/decoder.py", line 353, in raw_decode
[default_server_endpoint-1]     obj, end = self.scan_once(s, idx)
[default_server_endpoint-1]    

Types of change(s)

• Bug fix
• New feature
• Code refactor
• Documentation update
• Other (please describe)

Testing and Verification

• Tested together with the newest commit on the Unity ROS Teleoperation
• Tested Standalone

Test Configuration:

• Unity Version: 2022.3.12f1
• Unity machine OS + version: Kubuntu 24.04.3 LTS x86_64, 2022.3.12f1
• ROS machine OS + version: Kubuntu 24.04.3 LTS x86_64, ROS2 Jazzy
• ROS–Unity communication: Local (Both Natively run on OS)

Checklist

(Note there is no dev branch, hence I would guess a pr to main-ros2 is acceptable)

• Ensured this PR is up-to-date with the dev branch
• Created this PR to target the dev branch
• Followed the style guidelines as described in the Contribution Guidelines
• Added tests that prove my fix is effective or that my feature works
• Updated the Changelog and described changes in the Unreleased section
• Updated the documentation as appropriate

Other comments

None

[Soldann]

This looks great :D