Python script for FDX-B 15-digit, ISO-compliant Pet microchips

FDX-B.md

The script processes a raw HEX string input (representing an FDX-B transponder) and extracts relevant fields, such as the header, identification code, country code, data block status, animal application indicator, CRC checksum, and extended data block.

Key Features:

1. Dynamic Imports: It dynamically imports required libraries (binascii, argparse, termcolor), displaying errors if any library is missing.
2. HEX Processing: It converts the input HEX string into binary and extracts the fields following the FDX-B protocol structure.
3. Manufacturer Lookup: Based on the country code, it enriches the output by displaying the manufacturer's name (if available).
4. Colorful Output: Uses the termcolor library to colorize the output fields for better readability.
5. Error Handling:
   • If no HEX string is passed, it displays a usage guide and prompts the user to provide valid input.
   • If an invalid HEX string is passed, it catches the error and prints a helpful message.

The script is run via the command line, and the user must provide the HEX string as an argument for it to process the data.

The Python Script:

import sys

# Dynamically import required libraries
libnames = ['binascii', 'argparse', 'termcolor']
for libname in libnames:
    try:
        lib = __import__(libname)
    except:
        print(f"Failed to import {libname}: ", sys.exc_info())
    else:
        globals()[libname] = lib

# List of known manufacturers and their ISO codes
manufacturers = {
    985: "Destron",
    982: "Allflex",
    981: "Datamars",
    978: "Ordicam",
    977: "Avid",
    975: "Sokymat",
    972: "Planet ID",
    968: "AEG",
    967: "Rfdynamics",
    966: "PetCode",
    965: "4D Technology Co. Ltd.",
    963: "Korth Eletro Mecanica LTDA",
    961: "Mannings I.A.I.D.",
    959: "Global ID Technologies",
    958: "Pet ID",
    956: "Trovan Ltd.",
    955: "Reseaumatique",
    953: "Cromasa Identificacion electronica S.A.",
    952: "JECTA"
}

# Function to process the HEX input
def process_hex(hex_string):
    try:
        # Remove spaces and convert hex string to binary
        hex_clean = hex_string.replace(" ", "")
        binary_data = bin(int(hex_clean, 16))[2:].zfill(len(hex_clean) * 4)

        # Extract fields from the binary data
        header = binary_data[:11]  # 11-bit header
        identification_data = binary_data[11:49]  # 38-bit identification code
        country_code_binary = binary_data[49:59]  # 10-bit country code
        data_block_status = binary_data[59]  # 1-bit data block status
        animal_indicator = binary_data[60]  # 1-bit animal indicator
        crc = binary_data[61:77]  # 16-bit CRC
        extended_data_block = binary_data[77:101]  # 24-bit extended data block

        # Convert fields to relevant formats
        country_code = int(country_code_binary, 2)
        identification_code = int(identification_data, 2)
        
        # Enrich manufacturer information
        manufacturer_name = manufacturers.get(country_code, "Unknown")

        # Print the fields with color
        print(termcolor.colored(f"Header: {header} (11-bit)", "yellow"))
        print(termcolor.colored(f"Identification Code: {identification_code} (12-digit code)", "cyan"))
        print(termcolor.colored(f"Country Code: {country_code} (Manufacturer: {manufacturer_name})", "green"))
        print(termcolor.colored(f"Data Block Status: {data_block_status} (1-bit)", "yellow"))
        print(termcolor.colored(f"Animal Application Indicator: {animal_indicator} (1-bit)", "cyan"))
        print(termcolor.colored(f"CRC Checksum: {crc} (16-bit)", "red"))
        print(termcolor.colored(f"Extended Data Block: {extended_data_block} (24-bit)", "green"))
    
    except ValueError:
        print(termcolor.colored("Error: Invalid HEX string. Please provide a valid HEX string.", "red"))

# Command-line argument parser with error handling
def main():
    parser = argparse.ArgumentParser(description="Process raw HEX input from an FDX-B transponder.")
    parser.add_argument("hex_string", nargs="?", help="The raw HEX string to process (e.g., 'C2 28 EE 12 E9 6F 00 01 00 00 00')")
    
    args = parser.parse_args()
    
    if not args.hex_string:
        print(termcolor.colored("Error: No HEX string provided. Please provide a valid HEX string as a command-line argument.", "red"))
        parser.print_help()
    else:
        process_hex(args.hex_string)

if __name__ == "__main__":
    main()

Error Handling:

1. Error Handling for Missing Input:

   • If no string is passed, the script will display a usage message using argparse.print_help() along with an error message.

2. Error Handling for Invalid HEX Strings:

   • If an invalid HEX string (i.e., a string that can't be converted to a valid hexadecimal number) is passed, it will catch the ValueError and print a user-friendly error message indicating the issue.

3. argparse Settings:

   • nargs="?" is used to allow the HEX string argument to be optional, and the script can then handle the case where it’s missing.

How to Run the Script:

• If you pass a valid HEX string:

python process_transponder.py "C2 28 EE 12 E9 6F 00 01 00 00 00"

• If you pass an invalid HEX string:

python process_transponder.py "InvalidString"

• If no string is passed:

python process_transponder.py

Example Output for Missing Input:

Error: No HEX string provided. Please provide a valid HEX string as a command-line argument.
usage: process_transponder.py [-h] [hex_string]
Process raw HEX input from an FDX-B transponder.

positional arguments:
  hex_string  The raw HEX string to process (e.g., 'C2 28 EE 12 E9 6F 00 01 00 00 00')

optional arguments:
  -h, --help  show this help message and exit

Example Output for Invalid HEX String:

Error: Invalid HEX string. Please provide a valid HEX string.

This ensures that the script is robust, handles errors gracefully, and gives clear feedback to the user when something is wrong.