canviz 0.1.0

Open-source browser-based CAN bus analyzer

CANvas Backend

FastAPI + python-can backend for the CANvas CAN bus analyzer.

Quick Start

cd backend

# Install (includes gs_usb support)
pip install -e ".[gs_usb]"

# Run with virtual bus (no hardware needed)
canvaz --interface virtual

# Run with FYSETC UCAN / any Candlelight-firmware device (Windows)
canvaz --interface gs_usb

# Run with slcan (COM port) device
canvaz --interface slcan --channel COM3 --bitrate 500000

# Run on Raspberry Pi (SocketCAN)
canvaz --interface socketcan --channel can0 --bitrate 500000

Browser opens automatically at http://localhost:8080. API docs at http://localhost:8080/docs.

Run Tests (no hardware needed)

pip install -e ".[dev]"
pytest tests/ -v

API Summary

Method	Path	Description
POST	/connect	Open CAN interface
POST	/disconnect	Close interface
GET	/status	Connection state
POST	/send	Transmit a frame
WS	/ws/frames	Live frame stream
POST	/dbc/load	Upload DBC file
GET	/dbc/messages	List decoded messages
DELETE	/dbc	Unload DBC
POST	/log/start	Start recording
POST	/log/stop	Stop recording
GET	/log/download/{file}	Download log file

Interface Notes

gs_usb (default): Targets Candlelight firmware — the default on FYSETC UCAN and most cheap CAN modules. Shows as "USB Composite Device" + "gs_usb" in Windows Device Manager. No COM port. No reflash needed.

slcan: For devices running slcan firmware that enumerate as a COM port. Pass --channel COM3 (or whatever port Windows assigns).

virtual: Software bus — frames loop back on themselves. Used for development and CI. No hardware required.

socketcan: Linux SocketCAN. Requires ip link set can0 up type can bitrate 500000 before starting. Works on Raspberry Pi and WSL2 with usbipd.