Question

Imagine a call center that cannot be inundated with customers by more than 2 calls per minute. So, anyone outside that range, would get an email support link ($bTrigger = FALSE). Everyone else ($bTrigger = TRUE) would get a tech support phone number.

The script is PHP. So, what’s the most efficient and accurate way to build this?

This is what I have so far, but unfortunately it’s only triggering once per minute. I can’t seem to figure out why it won’t run twice per minute.

<?php

$bTrigger = FALSE;
$sDir = dirname(__FILE__);
$sDir = rtrim($sDir,'/');
$sFile = $sDir . '/MINUTE-TIMER.txt';

$sLine = @ file_get_contents($sFile);
$sLine = str_replace("\r\n",'',$sLine);
$sLine = str_replace("\r",'',$sLine);
$sLine = str_replace("\n",'',$sLine);
$sLine = str_replace("\t",'',$sLine);
$asParts = explode(',',$sLine);
$nLetThru = @ $asParts[0];
$nLetThru = intval($nLetThru);
$nLastMin = @ $asParts[1];
$nLastMin = intval($nLastMin);
$nCurMin = intval(date('i'));
if (empty($sLine)) {
  $nLetThru = 0;
  $nLastMin = 0;
}

$nMaxLetThru = 2;

if ($nCurMin != $nLastMin) { // meaning, a new minute since last checked
  if ($nLetThru <= $nMaxLetThru) { // meaning, we haven't hit more than max allowed
    $bTrigger = TRUE;
    ++$nLetThru;
    file_put_contents($sFile,"$nLetThru,$nCurMin");
  } else {
    file_put_contents($sFile,"0,$nCurMin");
  }
}

if ($bTrigger) {
  echo 'TRIGGERED!!!!';
} else {
  echo 'not triggered';
}

Answer 1

The problem was a simple coding error: $nLetThru wasn’t being reset when the minute changed. (Also, your <= should have been <, but you already noticed that.)

Here’s the fixed code (based on the original version, in the question):

if (empty($sLine)) {
  $nLastMin = -1; # (instead of 0) just affects the 1st time thru, 1 chance in 60
}

…

if ($nCurMin != $nLastMin) { // new minute
  $bTrigger = TRUE;
  $nLetThru = 1;
} else { // another hit, same minute
  if ($nLetThru < $nMaxLetThru) { // not too many yet
    $bTrigger = TRUE;
    ++$nLetThru;
  }
}
if ($bTrigger) {
  file_put_contents($sFile,"$nLetThru,$nCurMin");
}