print_daemon.py

#!/usr/bin/env python

import os
import sys

from os import listdir
from os.path import isfile, join
from time import sleep


class PrintDaemon:

    def __init__(self, folder_to_scan = None):
        if folder_to_scan is not None:
            self.folder_to_scan = folder_to_scan

        self.file_list = [ f for f in listdir(self.folder_to_scan) if isfile(join(self.folder_to_scan,f)) ]
        for file in self.file_list:
            print "Ignoring %s..." % file

    def diff(self, a, b):
        return list(set(a) - set(b))

    def printFromFolder(self):
        while True:
            updated_file_list = [ f for f in listdir(self.folder_to_scan) if isfile(join(self.folder_to_scan,f)) ]
            new_items = self.diff(updated_file_list, self.file_list)
 
            for item in new_items:
                print "Printing %s..." % item
                os.system('convert %s %s +append /tmp/%s' % (item, item, item))
                os.system('lpr -o media="4x6" /tmp/%s' % item)

            self.file_list = updated_file_list

            sleep(1)         

if __name__ == '__main__':
    folder_to_scan = None

    if len(sys.argv) == 2:
        folder_to_scan = sys.argv[1]
    
    print_daemon = PrintDaemon(folder_to_scan)
    print_daemon.printFromFolder()