1 files changed, 54 insertions, 0 deletions
diff --git a/hosts/gnuslashprinter/resources/flaskrelayctl/server/__init__.py b/hosts/gnuslashprinter/resources/flaskrelayctl/server/__init__.py
new file mode 100644
index 0000000..f2c0bc3
--- /dev/null
+++ b/hosts/gnuslashprinter/resources/flaskrelayctl/server/__init__.py
@@ -0,0 +1,54 @@
+from flask import Flask, jsonify
+import serial
+import os
+
+app = Flask(__name__)
+
+RELAY_DEV  = os.environ.get("RELAYCTL_DEV", "/dev/ttyUSB0")
+RELAY_HOST = os.environ.get("RELAYCTL_HOST", "127.0.0.1")
+RELAY_PORT = os.environ.get("RELAYCTL_PORT", "5050")
+RELAY_BAUD = 9600
+RELAY_ID = 1  # NOTE: multi relay boards are not supported (only relay id 1)
+
+def get_cmd(state: bool):
+    """
+    LCUS relay 4-byte control command syntax is as follows:
+    start: always 0xA0
+    relay: id of relay (counts from 1)
+    state: coil energized 0 or 1
+    checksum: sum of previous 3 bytes
+    """
+    start = 0xA0
+    relay = RELAY_ID
+    state = int(state)
+    checksum = start + relay + state
+    return bytes((start, relay, state, checksum))
+
+def get_serial():
+    return serial.Serial(RELAY_DEV, RELAY_BAUD, timeout=1)
+
+@app.route("/on", methods=["GET", "POST"])
+def on():
+    with get_serial() as ser:
+        ser.write(get_cmd(True))
+        return jsonify({"state": "ON"})
+
+@app.route("/off", methods=["GET", "POST"])
+def off():
+    with get_serial() as ser:
+        ser.write(get_cmd(False))
+        return jsonify({"state": "OFF"})
+
+@app.route("/status", methods=["GET"])
+def status():
+    with get_serial() as ser:
+        ser.write(bytes((0xFF,)))  # write 0xFF to get status
+        r = ser.readline()
+        state = r.decode("utf-8").removeprefix("CH1: ").strip()
+        return jsonify({"state": state})
+
+def main():
+    app.run(host=RELAY_HOST, port=int(RELAY_PORT))
+
+if __name__ == "__main__":
+    main()