# python code for the Simple Internet Gizmo - instructable by talk2bruce
# 
# this program receives RFID tag numbers sent from Sparkfun RFID reader connected via USB.
# the tag is number is used to lookup the address of the web site associated
# with the tag. the program then opens a new tab in a web browser for that site.
# if an unknown tag is read, a small HTML file is constructed with an error
# message and the tag number. a new tab is opened in a web browser and the error
# information is displayed.  this error message can be used to for adding new tages:
# the tag number can be copied by the user and added to the dictionary and 
# associated with a new web site.

# this version for the Parallax RFID reader.  The Parallax RFID reader will
# continously read tags if they are in range so code is needed to detect whether
# duplicate tags have been read.

import sys            # library for system functions
import serial         # library for connecting to the rfid reader
import webbrowser     # library for opening web pages in a browser

# this dictionary is used to map RFID tag numbers to web sites
# to add a new tag, duplicate the last line and modify the tag and
# web site address (url)
tag_url_dictionary = {  
  '48001FD494'  : 'quit'  
  ,'48001FD227' : 'http://www.techshop.ws'
  ,'48001FD6FA' : 'http://www.arduino.cc'
  ,'2C00AC423E' : 'http://www.instructables.com'
  ,'48002038C1' : 'http://www.adafruit.com'
  ,'4800202481' : 'http://makerfaire.com'
  ,'48001FD404' : 'http://www.ebay.com'
  ,'480020380E' : 'http://www.gmail.com'
  ,'480020385D' : 'http://www.radioshack.com'
  ,'48001FD469' : 'http://www.facebook.com'
  ,'48001FD6CA' : 'http://www.amazon.com'
  ,'48001FD6E7' : 'http://www.twitter.com'
  ,'48002005CC' : 'http://mail.yahoo.com'
  }

# default port for the sparkfun rfid reader for my system - update to match your system
default_rfid_reader_port = "COM7"

# name of the file used for constructing error messages when tags not in the
# dictionary have been read.  this file will be created in the same directory
# as this program is located.
error_file = 'unknowntag.html'

# main program for reading and processing tags
def main(rfid_reader = default_rfid_reader_port):      
  print "Connecting to Sparkfun RFID reader on port ", rfid_reader
  try:
    ser = serial.Serial(rfid_reader, timeout=1)                 # connect to the rfid reader
    print "Successfully connected to RFID reader on ", rfid_reader
    rfid_reader_opened = 1
  except:
    print "Failed to connect to RFID reader on port ", rfid_reader
    rfid_reader_opened = 0

  # if the RFID reader was successfully connected, start reading and processing tags    
  if rfid_reader_opened:

    previous_rfid_tag = ''  # used for identifying whether the same tag has been read
  
    while 1:    # loop forever until a "quit" tag is read
  
      ser.flushInput()                    # flush any extra data from the serial port
      rfid_data = ser.readline().strip()  # read the  rfid data 

      # if data has been received
      if len(rfid_data) > 0:

        print "Tag data:", rfid_data                   # print the tag number

        # using the tag number, lookup the corresponding web site address
        url = translate_tag_to_url(tag_url_dictionary, rfid_data);
        print "tag = ", rfid_data, " url = ", url

        # check to see if the 'quit' tag was just read and if so stop the program
        if url == 'quit':
          break
        else:
          # if the last tag is different than the last one read, open the web page
          # ignore the tag is it was the same one as the one last read
          if rfid_data != previous_rfid_tag:
            webbrowser.open(url)                   # open the web site in a new tab in the default browser
            previous_rfid_tag = rfid_data          # remember what tag was just read    

# this function uses the tag number to look up the web site address (url)from the RFID tag number
def translate_tag_to_url(tag_dictionary, tag):

  if tag_dictionary.has_key(tag): # see if the tag is in the dictionary
    return tag_dictionary[tag]    # it's there so return the url associated with the tag
  else:    # tag isn't defined - build a HTML page with the error message in a temporary file
    # build the HTML file for the error message: it will look like "RFID tag not in the dictionary: xxxxxxxxxx"
    # where xxxxxxxxxx is the tag number.
    error_msg = '<html><title>Simple Internet Gizmo Error Message</title><body><font size="+3">'
    error_msg = error_msg + 'RFID tag not in the dictionary: ' + tag
    error_msg = error_msg + '</font></body></html>'
    f = open(error_file, 'w')   # open the file for writing
    f.writelines(error_msg)     # write the error message
    f.close                     # close the file
    return error_file           # return the file name

# this code enables starting the program from the command line
if __name__ == '__main__':
  if (len(sys.argv) > 1):
    main(sys.argv[1])
  else:
    main()