104 lines
2.4 KiB
Python
104 lines
2.4 KiB
Python
#!/usr/bin/python
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import sys
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from datetime import datetime
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import time
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import json
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import RPi.GPIO as IO
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import zmq
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# Magic numbers for PWM activation
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MOTOR_PIN = 19
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FREQUENCY = 100
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DUTYCYCLE = 100
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DURATION = 1.0
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# Address of the scanning service
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SCANSERVADDRESS = "tcp://localhost:5000"
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def timestamped(s):
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"""
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Prepends a timestamp to a string.
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"""
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return "[{:%Y-%m-%d %H:%M:%S}] {}".format(datetime.now(), s)
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def setup_pwm():
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"""
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Performs initialization for pulse width modulation.
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Returns the PWM object for the motor pin.
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"""
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IO.setwarnings(False)
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IO.setmode(IO.BCM)
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IO.setup(MOTOR_PIN, IO.OUT)
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p = IO.PWM(MOTOR_PIN, FREQUENCY)
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return p
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def unlock_door(p):
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"""
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Uses PWM to turn the motor connected to the door handle.
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"""
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try:
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p.start(DUTYCYCLE)
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time.sleep(DURATION)
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finally:
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p.stop()
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def read_loop():
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"""
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Simple REPL skeleton for validating scanned IDs.
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"""
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# Initialize zmq socket for reading in scanned barcodes
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context = zmq.Context()
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socket = context.socket(zmq.SUB)
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socket.setsockopt(zmq.SUBSCRIBE, "")
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socket.connect(SCANSERVADDRESS)
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# Initialize the PWM pin for opening the door
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pwm_pin = setup_pwm()
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# Open the log file in append mode
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log_file = open("./access.log", "a")
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log_file.write(timestamped("=== Door security initiated ===\n"))
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# Begin the loop
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while True:
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# Read in the ID
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code = socket.recv()
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# Load the access database
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# As long as the access list is small and the speed is unimportant,
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# the flexibility and update ability is worth reading from disk.
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raw = open("access.json", "r").read()
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try:
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access = json.loads(raw)
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except:
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log_file.write(timestamped("Could not load access file!"))
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sys.stderr.write("Could not load access file!")
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access = {}
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# Determine ID authorization
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if code not in access:
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authorized = False
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user = "unknown barcode"
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else:
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authorized = "authorized" in access[code] and access[code]["authorized"]
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user = access[code]["name"] if "name" in access[code] else code
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# If the user is not authorized, deny access
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if not authorized:
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s = timestamped("Denied {} ({})\n".format(code, user))
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log_file.write(s)
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print s,
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# If the user is authorized, perform the unlock procedure
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else:
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s = timestamped("Validated {} ({})\n".format(code, user))
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log_file.write(s)
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print s,
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# TODO: Play open tone
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if "sound" in access[code]:
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pass
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# Run unlock procedure
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unlock_door(pwm_pin)
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if __name__ == "__main__":
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read_loop()
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