DHT11 Temperature Sensor as HTTP Service

temp_server.py

#!/usr/bin/env python3

from argparse import ArgumentParser
from http.server import ThreadingHTTPServer, BaseHTTPRequestHandler
from json import dumps as json_dumps
from threading import Thread, RLock
from time import sleep

import Adafruit_DHT

GPIO_PIN_DEFAULT = 4

class Handler(BaseHTTPRequestHandler):
    CODE_INTERNAL_SERVER_ERROR = 500
    CODE_OK = 200
    CONTENT_TYPE = "application/json;charset=utf-8"

    protocol_version = "HTTP/1.1"
    error_content_type = CONTENT_TYPE
    error_message_format = json_dumps({"message": "%(explain)s"})

    def do_GET(self):
        self.send_response(Handler.CODE_OK)
        self.send_header("Content-Type", Handler.CONTENT_TYPE)
        
        response = json_dumps(self.server.sensor_data).encode("utf-8")
        self.send_header("Content-Length", len(response))
        self.end_headers()

        self.wfile.write(response)


class Server(ThreadingHTTPServer):
    SENSOR_POLL_INTERVAL = 1
    allow_reuse_address = True

    def __init__(self, address, handler, gpio_pin):
        super().__init__(address, handler)
        self._sensor_data = {"humidity": 0, "temperature": 0}
        self._sensor_lock = RLock()
        self._sensor_thread = Thread(
            target=Server.poll_sensor, 
            args=(self._sensor_lock, gpio_pin, self._sensor_data), 
            daemon=True
        )
        self._sensor_thread.start()

    @property
    def sensor_data(self):
        with self._sensor_lock:
            return self._sensor_data

    @staticmethod
    def poll_sensor(lock, gpio_pin, data):
        while True:
            humidity, temperature = Adafruit_DHT.read_retry(Adafruit_DHT.DHT11, gpio_pin)
            with lock:
                data["humidity"] = humidity
                data["temperature"] = temperature
            sleep(Server.SENSOR_POLL_INTERVAL)


if __name__ == "__main__":
    parser = ArgumentParser(description="Temperature and Humidity Server")
    parser.add_argument("port", type=int, help="The port to the the server on")
    parser.add_argument("--gpio-pin", type=int, help="The GPIO pin that the sensor is connected to", default=GPIO_PIN_DEFAULT)

    args = parser.parse_args()

    with Server(("0.0.0.0", args.port), Handler, args.gpio_pin) as httpd:
        print("Server running on port {}...".format(args.port))
        try:
            httpd.serve_forever()
        except KeyboardInterrupt:
            httpd.shutdown()