scan.py

#! /usr/bin/python
import sys, getopt
import struct, time
import httplib, json

def addToCart(server, barcode):
	c = httplib.HTTPConnection(server)
	c.request("GET", "/barcode/" + barcode)
	r = c.getresponse()

	if r.status != 200:
		print "Lookup failed:", barcode
		return

	resp = r.read()
	print resp
	data = json.loads(resp)['barcode']
	name = data['name']

	#
	# Insert new item.
	#
	item = {
		'item': {
			'code': barcode,
			'name': name,
			'count': 1,
			'done': 0
		}
	}
	body = json.dumps(item, sort_keys=True, indent=4)
	print body

	c = httplib.HTTPConnection(server)
	c.request("POST", "/list/1/item", body)
	r = c.getresponse()

	print r.status, r.reason
	if r.status == 200:
		return

	#
	# Update existing item.
	#
	resp = r.read()
	print resp
	data = json.loads(resp)
	if data['error'] == "Item already exists.":
		item = {
			'item': {
				'count': data['item']['count'] + 1,
				'done': 0
			}
		}
		body = json.dumps(item, sort_keys=True, indent=4)
		c = httplib.HTTPConnection(server)
		c.request("PUT", "/list/1/item/" + str(data['item']['id']), body)
		r = c.getresponse()
		print r.status, r.reason

#https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/input-event-codes.h
scancodes = {
    0: None, 1: u'ESC', 2: u'1', 3: u'2', 4: u'3', 5: u'4', 6: u'5', 7: u'6', 8: u'7', 9: u'8',
    10: u'9', 11: u'0', 12: u'-', 13: u'=', 14: u'BKSP', 15: u'TAB', 16: u'q', 17: u'w', 18: u'e', 19: u'r',
    20: u't', 21: u'y', 22: u'u', 23: u'i', 24: u'o', 25: u'p', 26: u'[', 27: u']', 28: u'ENTER', 29: u'LCTRL',
    30: u'a', 31: u's', 32: u'd', 33: u'f', 34: u'g', 35: u'h', 36: u'j', 37: u'k', 38: u'l', 39: u';',
    40: u'"', 41: u'`', 42: u'LSHFT', 43: u'\\', 44: u'z', 45: u'x', 46: u'c', 47: u'v', 48: u'b', 49: u'n',
    50: u'm', 51: u',', 52: u'.', 53: u'/', 54: u'RSHFT', 55: u'CAPS', 56: u'LALT', 96: u'ENTER', 100: u'RALT'
}
capscodes = {
    0: None, 1: u'ESC', 2: u'!', 3: u'@', 4: u'#', 5: u'$', 6: u'%', 7: u'^', 8: u'&', 9: u'*',
    10: u'(', 11: u')', 12: u'_', 13: u'+', 14: u'BKSP', 15: u'TAB', 16: u'Q', 17: u'W', 18: u'E', 19: u'R',
    20: u'T', 21: u'Y', 22: u'U', 23: u'I', 24: u'O', 25: u'P', 26: u'{', 27: u'}', 28: u'ENTER', 29: u'LCTRL',
    30: u'A', 31: u'S', 32: u'D', 33: u'F', 34: u'G', 35: u'H', 36: u'J', 37: u'K', 38: u'L', 39: u':',
    40: u'\'', 41: u'~', 42: u'LSHFT', 43: u'|', 44: u'Z', 45: u'X', 46: u'C', 47: u'V', 48: u'B', 49: u'N',
    50: u'M', 51: u'<', 52: u'>', 53: u'?', 54: u'RSHFT', 55: u'CAPS', 56: u'LALT', 96: u'ENTER', 100: u'RALT'
}

def scanBarcodesRawDevice(server, device):

	#long int, long int, unsigned short, unsigned short, unsigned int
	eventFormat = 'llHHI'
	eventSize = struct.calcsize(eventFormat)

	# I.e. /dev/input/event4
	kb = open(device, 'rb')

	string = ''
	caps=False

	while True:
		event = kb.read(eventSize)
		(tv_sec, tv_usec, etype, code, value) = struct.unpack(eventFormat, event)

		# Skip everything except key events.
		if etype != 1:
			continue

		# Shift and caps lock.
		if code == 42 or code == 54:
			caps = False if value == 0 else True
			continue
		if code == 55 and value != 0:
			caps = not caps
			continue

		# Skip release events.
		if value == 0:
			continue

		# Skip some specific non-character codes.
		if code in (1,14,15,29,42,54,56,100):
			continue

		# Enter.
		if code == 28 or code == 96:
			print '\nRead string:', string
			addToCart(server, string)
			string = ''
			continue

		table = capscodes if caps else scancodes

		if code not in table:
			print("Event type %u, code %u, value %u at %d.%d" % \
				(etype, code, value, tv_sec, tv_usec))
			continue

		key = table[code]
		string += key

		sys.stdout.write(key)
		sys.stdout.flush()

	# Close raw device.
	kb.close()

def scanBarcodesSTDIN(server):
	while True:
		string = raw_input("Enter barcode: ").rstrip()
		print string
		addToCart(server, string)

options = [ 
    ('h','help','This help.'),
    ('s:','server=','Shopping cart server.'),
    ('d:','device=','Input device path.')]
shortOpt = "".join([opt[0] for opt in options])
longOpt = [opt[1] for opt in options]

def usage():
    pad = str(len(max(longOpt, key=len)))
    fmt = '  -%s, --%-'+pad+'s : %s'
    print 'Usage: '+sys.argv[0]+' [options]\n'
    for opt in options:
        print fmt%(opt[0][0], opt[1], opt[2])
    sys.exit(2)

def main():
	try:
		opts, args = getopt.getopt(sys.argv[1:], shortOpt, longOpt)
	except getopt.GetoptError as err:
		print str(err)
		usage()

	server = 'localhost:8888'
	device = None

	for o, a in opts:
		if o in ('-h', '--help'):
			usage()
		elif o in ('-s', '--server='):
			server = a
		elif o in ('-d', '--device='):
			device = a
		else:
			assert False, 'Unhandled option: ' + str(o)

	if device is None:
		scanBarcodesSTDIN(server)
	else:
		scanBarcodesRawDevice(server, device)

if __name__ == "__main__":
    main()