一个完整php验证码实例程序[带demo]

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 user:


 password:


 pincode:
 
   
 

require_once("log_aux.php");

if ($_get['a'] == "pin") {
 getpinimg();
 exit;
}

if ($_get['a'] == "log") {
 $ret = checkpincookie($_get['pin'], 300);
 if ($ret < 0) {
  echo "pin error:$ret ";
  exit;
 }
 // check user name and password.
 echo "ok..$ret ";
 if ("123xx" == 123) {
  echo "dddd ";
 }
 echo $_get['u'];
}

$magic_a = "www.111com.net34589";
$magic_b = "234566***+";

function getpincookie($pin_code)
{
 global $magic_a;
 global $magic_b;
 $now = time();
 $client_ip = $_server['remote_addr'];
 $pin = md5($now . $client_ip . $magic_a . $pin_code . $maigc_b) . $now;
 return $pin;
}

function checkpincookie($pin_code_in, $timeout=300) // 5 miniuteswww.111com.net
{
 global $magic_a;
 global $magic_b;
 $pin = substr($_cookie['pin'], 0, 32);
 $time = substr($_cookie['pin'], 32);
 $now = time();
 if ($now - $time > $timeout) {
  return -100;  // time_out
 }
 $pin_code_in = strtolower($pin_code_in);
 $client_ip = $_server['remote_addr'];
 $pin_2 = md5($time . $client_ip . $magic_a . $pin_code_in . $maigc_b);
 if ($pin === $pin_2) {
  return 0;
 } else {
  return -200; // pincode is error.
 }
}

function getpinimg()
{
// $rnd = rand(0, 10);
 $rnd = 0;
 $path = "./www.111com.net/" . substr("00000$rnd", -4);
 for ($i = 0; $i < 4; ++$i) {
  if (__getpinimg($path)) {
   break;
  }
 }
 exit;
}

function __getpinimg($path)
{
 require("$path/pinmap.php");
 $pinv = $pin[rand(0, $pin_max)];
 list ($file, $pin_code) = explode('#', $pinv);
 $filepath = "$path/$file$pin_ext";

 //  output pincode image.
 $fh = fopen($filepath, "rb");
 if (!$fh) {
  return false;
 }
 $data = fread($fh, 10240); // php just read max size: 8k.
 fclose($fh);

 if (strlen($data) < 200) {
  return false;
 }
 // set cookie;
 header("content-type: image/jpeg");
 $pin_code = strtolower($pin_code);
 $pin = getpincookie($pin_code);
 setcookie("pin", $pin);

 echo $data;
 return true;
}