smartproxyping.php

AJAX and PHP: Building Responsive Web Applications源代码

<?php
// load the error handling module
require_once('error_handler.php');
// make sure the user's browser doesn't cache the result
header('Expires: Wed, 23 Dec 1980 00:30:00 GMT'); // time in the past
header('Last-Modified: ' . gmdate('D, d M Y H:i:s') . ' GMT');
header('Cache-Control: no-cache, must-revalidate');
header('Pragma: no-cache');
// retrieve the action parameter
$action = $_GET['action'];
// check availability or get new random number?
if ($action == 'GetNumber')
{
  $num = 1; // value is hardcoded because client can't deal with more numbers
  $min = $_GET['min'];
  $max = $_GET['max'];
  // holds the remote server address and parameters
  $serverAddress = 'http://www.random.org/cgi-bin/randnum';
  $serverParams = 'num=' . $num . // how many random numbers to generate
                  '&min=' . $min . // the min number to generate
                  '&max=' . $max; // the max number to generate
  // retrieve the random number from foreign server
  $randomNumber = file_get_contents($serverAddress . '?' . $serverParams);
  // output the random number
  echo $randomNumber;
}
elseif ($action == 'CheckAvailability')
{
  // address of page that returns buffer level
  $serverAddress = 'http://www.random.org/cgi-bin/checkbuf';
  // received buffer level is in form 'x%'
  $bufferPercent = file_get_contents($serverAddress);
  // extract the number 
  $buffer = substr($bufferPercent, 0, strlen($bufferPercent) - 2);
  // echo the number
  echo $buffer;
}
else
{
  echo 'Error talking to the server.';
}
?>