Drivers for the barcode and the rfid scanner

Author: kjagiello

drivers/barcode.py

@@ -0,0 +1,66 @@
+import argparse
+import logging
+from thunderclient import Thunder
+from evdev import InputDevice, list_devices, ecodes
+from evdev import categorize
+
+logger = logging.getLogger(__name__)
+
+
+def read_codes(device):
+    events = (e for e in device.read_loop() if e.type == ecodes.EV_KEY)
+    events = map(categorize, events)
+    events = (e for e in events if e.keystate == e.key_up)
+
+    buff = []
+
+    for e in events:
+        if e.scancode == ecodes.KEY_ENTER:
+            ascii = [e.keycode.split('_')[1] for e in buff]
+            buff = []
+            yield ''.join(ascii)
+        else:
+            buff.append(e)
+
+
+def main(device_name, host, port, apikey, apisecret, verbose=False):
+    # Configure logging to the console if requested.
+    if verbose:
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.DEBUG)
+        logger.addHandler(handler)
+        logger.setLevel(logging.DEBUG)
+
+    devices = map(InputDevice, list_devices())
+    devices = [d for d in devices if d.name.strip() == device_name]
+
+    assert devices, ('No Barcode Reader device found (did you forget to run '
+                     'the script as root?).')
+
+    device = devices[0]
+    device.grab()
+
+    logger.debug('Connected to \'%s\'.', device.name.strip())
+    tc = Thunder(apikey, apisecret, host, port)
+
+    for code in read_codes(device):
+        tc.send_message_to_channel('products', code)
+        logger.debug('Code %s has been sent to the \'products\' channel.', code)
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('device', type=str,
+                        help='The name of the device to read from.')
+    parser.add_argument('host', type=str,
+                        help='Thunderpush host to communicate with.')
+    parser.add_argument('apikey', type=str)
+    parser.add_argument('apisecret', type=str)
+    parser.add_argument('--port', type=int, default=80,
+                        help='Thunderpush port (default 80).')
+    parser.add_argument('-v', '--verbose', help='Increase output verbosity.',
+                        action='store_true')
+    args = parser.parse_args()
+    main(args.device, args.host, args.port, args.apikey, args.apisecret,
+         args.verbose)
+

drivers/rfid.py

@@ -0,0 +1,93 @@
+import time
+import serial
+import logging
+import argparse
+import redis
+from functools import wraps
+
+logger = logging.getLogger(__name__)
+
+
+def throttle(seconds):
+    def decorator(func):
+        func.last_call = 0
+
+        def reset_timer():
+            func.reset_timer = 0
+
+        func.reset_timer = reset_timer
+
+        @wraps(func)
+        def wrapper(*args, **kwargs):
+            if time.time() - func.last_call > seconds:
+                func.last_call = time.time()
+                return func(*args, **kwargs)
+        return wrapper
+    return decorator
+
+
+@throttle(seconds=1)
+def parse_code(data):
+    try:
+        return int('0x{}'.format(data.decode('ascii').strip()), 16)
+    except ValueError:
+        # Invalid value has been read. Discard it and do not wait before
+        # reading the next value.
+        parse_code.reset_timer()
+        return None
+
+
+def parse_codes(ser):
+    while True:
+        code = parse_code(ser.readline())
+        if code is not None:
+            yield code
+
+
+def main(dev, rate, host, port, channel, verbose):
+    # Configure logging to the console if requested.
+    if verbose:
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.DEBUG)
+        logger.addHandler(handler)
+        logger.setLevel(logging.DEBUG)
+
+    r = redis.StrictRedis(
+        host=host,
+        port=port
+    )
+
+    logger.debug('Starting reading from %s with baud rate %d.', dev, rate)
+    with serial.Serial(dev, rate) as ser:
+        # Discard the first value as it contains just a welcome message
+        ser.readline()
+        logger.debug('The connection has been estabilished and the '
+                     'welcome message read.')
+
+        try:
+            for code in parse_codes(ser):
+                r.publish(channel, code)
+                logger.debug('Code %d has been sent to the \'%s\' channel.',
+                             channel, code)
+        except KeyboardInterrupt:
+            logger.debug('CTRL-C received. Shutting down...')
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(
+        description='Listens for input from a RFID reader and publishes it '
+                    'to a Redis channel.'
+    )
+    parser.add_argument('device', type=str, help='A device file to read from.')
+    parser.add_argument('--channel', type=str, default='cards',
+                        help='Redis channel to send messages to.')
+    parser.add_argument('--host', type=str, default='localhost',
+                        help='Redis host (default localhost).')
+    parser.add_argument('--port', type=int, default=6379,
+                        help='Redis port (default 6379).')
+    parser.add_argument('--rate', type=int, default=115200,
+                        help='The baud rate (default: 115200).')
+    parser.add_argument('-v', '--verbose', help='Increase output verbosity.',
+                        action='store_true')
+    args = parser.parse_args()
+    main(**vars(args))

drivers/rfid_forwarder.py

@@ -0,0 +1,52 @@
+import logging
+import argparse
+import redis
+from thunderclient import Thunder
+
+logger = logging.getLogger(__name__)
+
+
+def main(apikey, apisecret, rhost, rport, rchannel, thost, tport, tchannel,
+         verbose=False):
+    # Configure logging to the console if requested.
+    if verbose:
+        handler = logging.StreamHandler()
+        handler.setLevel(logging.DEBUG)
+        logger.addHandler(handler)
+        logger.setLevel(logging.DEBUG)
+
+    tc = Thunder(apikey, apisecret, thost, tport)
+    r = redis.StrictRedis(host=rhost, port=rport)
+    p = r.pubsub()
+    p.subscribe(rchannel)
+
+    try:
+        for msg in filter(lambda msg: msg['type'] == 'message', p.listen()):
+
+            code = int(msg['data'].decode('utf-8'))
+            tc.send_message_to_channel('cards', code)
+            logger.debug('Code %d has been forwarded.', code)
+    except KeyboardInterrupt:
+        logger.debug('CTRL-C received. Shutting down...')
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser()
+    parser.add_argument('apikey', type=str)
+    parser.add_argument('apisecret', type=str)
+    parser.add_argument('--thost', type=str, default='localhost',
+                        help='Thunderpush host (default: localhost).')
+    parser.add_argument('--tchannel', type=str, default='cards',
+                        help='Thunderpush channel name (default: cards).')
+    parser.add_argument('--tport', type=int, default=80,
+                        help='Thunderpush port (default: 80).')
+    parser.add_argument('--rhost', type=str, default='localhost',
+                        help='Redis host (default: localhost).')
+    parser.add_argument('--rport', type=int, default=6379,
+                        help='Redis port (default: 6379).')
+    parser.add_argument('--rchannel', type=str, default='cards',
+                        help='Redis channel name (default: cards).')
+    parser.add_argument('-v', '--verbose', help='Increase output verbosity.',
+                        action='store_true')
+    args = parser.parse_args()
+    main(**vars(args))