barcode.py

# Import the PyOTA library
import iota
from iota import Address
from iota import Transaction
from iota import TryteString
from iota.crypto.kerl import Kerl

# Import datetime libary
import datetime

# Import from PrettyTable
from prettytable import PrettyTable

# Import requests
import requests

# Import json
import json

# Set UPC URL and KEY
upcURL = "https://api.upcdatabase.org/product"
upcKEY = "BC5BD15B042DF904FE3ACC7FE3EBDE3C"

# Define full node to be used when uploading/downloading inventory records from the tangle
NodeURL = "https://nodes.thetangle.org:443"

# Create IOTA object
api=iota.Iota(NodeURL)

# Function for generating addresses based on a UPC item ID
def CreateAddress(upc_ID):

  upc_tryte = TryteString.from_unicode(upc_ID)
  astrits = TryteString(str(upc_tryte).encode()).as_trits()
  checksum_trits = []
  sponge = Kerl()
  sponge.absorb(astrits)
  sponge.squeeze(checksum_trits)
  result = TryteString.from_trits(checksum_trits) 
  new_address = Address(result)
  return(new_address.with_valid_checksum())

# Function for adding/removing items from stock
def UpdateStock(stock_change):

  # Get barcode ID
  upc_ID = input("Scan barcode..:")

  # Get stock change quantity
  qty = input("Specify quantity: ")

  # Create upload json
  udata = {'Stock Change' : stock_change, 'Quantity' : qty}
  mystring = json.dumps(udata)

  # Create address based on UPC code
  addr = CreateAddress(upc_ID)

  # Define new IOTA transaction
  pt = iota.ProposedTransaction(address = iota.Address(addr), message = iota.TryteString.from_unicode(mystring), tag = iota.Tag(b'HOTELIOTA'), value=0)

  # Print waiting message
  print("\nSending transaction...Please wait...")

  # Send transaction to the tangle
  FinalBundle = api.send_transfer(depth=3, transfers=[pt], min_weight_magnitude=14)['bundle']
    
  # Print confirmation message 
  print("\nTransaction completed.")

  print("\nIOTA address used for the transaction was:")
  print(addr)


def StockReport():
  
  # Get barcode from scanner..
  upc_ID = input("Scan barcode..:")

  # Get IOTA address where item records is stored
  addr = CreateAddress(upc_ID)
  Address = []
  Address.append(addr)

  # Create PrettyTable object
  x = PrettyTable()

  # Specify column headers for the table
  x.field_names = ["Stock Change", "Quantity", "Date/Time"]

  # Find all transacions for selected IOTA address
  result = api.find_transactions(addresses=Address)
    
  # Create a list of transaction hashes
  myhashes = result['hashes']

  # Print wait message
  print("\nPlease wait while retrieving inventory records from the tangle...")

  # Get item data from UPC database
  upc_lookup = upcURL + "/" + upc_ID + "/" + upcKEY
  upc_data = requests.get(upc_lookup).json()

  # Print UPC item data to the terminal
  if upc_data['status'] == 200:
    print("\nUPC item title: " + upc_data['title'])
    print("UPC item description: " + upc_data['description'])
  else:
    print("\nItem was not found in UPC database")

  # Define items in stock counter
  in_stock = 0

  # Loop trough all transaction hashes
  for txn_hash in myhashes:
    
    # Convert to bytes
    txn_hash_as_bytes = bytes(txn_hash)

    # Get the raw transaction data (trytes) of transaction
    gt_result = api.get_trytes([txn_hash_as_bytes])
    
    # Convert to string
    trytes = str(gt_result['trytes'][0])
    
    # Get transaction object
    txn = Transaction.from_tryte_string(trytes)
    
    # Get transaction timestamp
    timestamp = txn.timestamp
    
    # Convert timestamp to datetime
    change_time = datetime.datetime.fromtimestamp(timestamp).strftime('%Y-%m-%d %H:%M:%S')

    # Get transaction message as string
    txn_data = str(txn.signature_message_fragment.decode())
    
    # Convert to json
    json_data = json.loads(txn_data)
    
    # Check if json data has the expected json tag's
    if all(key in json.dumps(json_data) for key in ["Stock Change","Quantity"]):
        # Add table row with json values
        x.add_row([json_data['Stock Change'], json_data['Quantity'], change_time])

        # Get transaction item quantity and appenf/subtract from total quantity 
        if json_data['Stock Change'] == "+":
          in_stock = in_stock + int(json_data['Quantity'])
        elif json_data['Stock Change'] == "-":
          in_stock = in_stock - int(json_data['Quantity'])

  # Sort table by datetime
  x.sortby = "Date/Time"

  # Print table to terminal
  print(x)

  # Print item quantity currently in stock
  print("Items currently in stock: " + str(in_stock))
  
# Show main menu
ans=True
while ans:
  print ("""
  1. Add to stock
  2. Remove from stock
  3. Stock report
  4. Exit
  """)
  # Get menu selection
  itemID = input("Select from menu:")
  if itemID=="1":
    UpdateStock("+")
  elif itemID=="2":
    UpdateStock("-")
  elif itemID=="3":
    StockReport()
  elif itemID=="4":
    exit()