sfdc_ids.py

import re
import logging


def validate_id(candidate_id):
    value = -1  # default return value if validation doesn't pass

    if bool(re.match('^[0-9a-zA-Z]{15}$', candidate_id)):
        value = 15
    elif bool(re.match('^[0-9a-zA-Z]{15}[0-5a-zA-Z]{3}$', candidate_id)):
        if bool(re.match('^[a-z]{3}', candidate_id[-3:])):
            logging.warning("Last 3 digits of 18-digit ID not capitalized, "
                            "ID might have been mangled by another process.")
        value = 18

    return value


def get_caps(input_string):
    caps_nums = []
    for starts in [0, 5, 10]:
        caps_num = 0
        chars = input_string[starts:starts+5]
        for i in range(5):
            caps_num += 2**i if chars[i].isupper() else 0
        caps_nums.append(caps_num)

    # convert each char to base 32, represented by [A-Z0-5] in that order
    caps_chars = [str(i-26) if i > 25 else chr(i+ord('A')) for i in caps_nums]

    return ''.join(caps_chars)


def fifteen_to_eighteen(input_id):
    caps = get_caps(input_id)
    return input_id+caps


def eighteen_to_fifteen(input_id):
    first_fifteen = input_id[:15]
    last_three = input_id[15:18].upper()
    caps = get_caps(first_fifteen)  # for casing validation
    if last_three != caps:
        logging.warning("Last 3 digits of 18-digit ID don't match computed"
                        "digits from casing of first 15 digits, coercing"
                        "casing as specified by last 3 digits.")
        last_three_nums = [int(iletter)+26 if ord(iletter) < ord('A')
                           else ord(iletter)-ord('A')
                           for iletter in last_three]
        last_three_masks = [format(inum, '05b')[::-1]
                            for inum in last_three_nums]
        mask = ''.join(last_three_masks)
        output_array = [first_fifteen[i].upper() if mask[i] == '1'
                        else first_fifteen[i].lower() for i in range(15)]
        output_id = ''.join(output_array)
    else:
        output_id = first_fifteen

    return output_id


def convert(input_id):

    id_check = validate_id(input_id)  # length of ID if valid, else -1

    if id_check == 15:
        output_id = fifteen_to_eighteen(input_id)
    elif id_check == 18:
        output_id = eighteen_to_fifteen(input_id)
    else:
        logging.error("Invalid SFDC ID given; no conversion performed")
        output_id = input_id

    return output_id