Creates a stub for a URL based on a string and the current time. (JavaScript, PHP & Python)

get_stub.php

<?php
function get_stub($str_start, $opt_max_length=15, $opt_chars="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") {
  $number = intval(microtime(true) * 1e3);
  $s = "";
  $l = strlen($opt_chars);
  while (number) {
    $remainder = $number % $l;
    $number = ($number - $remainder) / $l;
    $s = substr($opt_chars, $remainder, 1) . $s;
  }
  $number = $opt_max_length - strlen($s) - 1;
  return $number > 0 ? substr($str_start, 0, $number) . "-$s" : null;
}

get_stub.py

import time
def get_stub(str_start, opt_max_length=15, opt_chars="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789"):
  number = int(round(time.time() * 1e3))
  s = ""
  l = len(opt_chars)
  while number > 0:
    remainder = number % l
    number /= l
    s = opt_chars[remainder] + s
  number = opt_max_length - len(s) - 1
  return (str_start[0:number] + "-" + s) if number > 0 else None

getStub.es6.js

/**
 * Gets a stub string based on the given prefix and the time while limiting the
 * stub's length.
 * @param {string} prefix
 *   Prefix to start the stub with.  This prefix may be cut short to accomodate
 *   for the time part of the string.
 * @param {number=} opt_maxLength
 *   Defaults to 15.  The maximum length of the returned stub.
 * @param {string=} opt_chars
 *   Defaults to the characters A to Z followed by the characters a to z
 *   followed by the numbers 0 to 9.  Characters used to represent the current
 *   time (milliseconds).
 * @returns {?string}
 *   If the string the represents the time (epoch) is less than maximum length
 *   minus 1 a stub starting at least part of the prefix, followed by a dash
 *   ("-"), followed the epoch representation will be returned.  Otherwise null
 *   is returned.
 */
function getStub(prefix, opt_maxLength=15, opt_chars='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789') {
  for (var remainder, number = +new Date, s = '', l = opt_chars.length; number; ) {
    remainder = number % l;
    number = (number - remainder) / l;
    s = opt_chars.charAt(remainder) + s;
  }
  number = opt_maxLength - s.length - 1;
  return number > 0 ? prefix.slice(0, number) + '-' + s : null;
}

getStub.js

/**
 * Gets a stub string based on the given prefix and the time while limiting the
 * stub's length.
 * @param {string} prefix
 *   Prefix to start the stub with.  This prefix may be cut short to accomodate
 *   for the time part of the string.
 * @param {number=} opt_maxLength
 *   Defaults to 15.  The maximum length of the returned stub.
 * @param {string=} opt_chars
 *   Defaults to the characters A to Z followed by the characters a to z
 *   followed by the numbers 0 to 9.  Characters used to represent the current
 *   time (milliseconds).
 * @returns {?string}
 *   If the string the represents the time (epoch) is less than maximum length
 *   minus 1 a stub starting at least part of the prefix, followed by a dash
 *   ("-"), followed the epoch representation will be returned.  Otherwise null
 *   is returned.
 */
function getStub(prefix, opt_maxLength, opt_chars) {
  opt_maxLength = opt_maxLength || 15;
  opt_chars = opt_chars || 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
  for (var remainder, number = +new Date, s = '', l = opt_chars.length; number; ) {
    remainder = number % l;
    number = (number - remainder) / l;
    s = opt_chars.charAt(remainder) + s;
  }
  number = opt_maxLength - s.length - 1;
  return number > 0 ? prefix.slice(0, number) + '-' + s : null;
}