PHP 生成验证码

这个是在user.php下的一个action：

function scode(){

//include_once( __DIR__.'/include.php' );

Header("Content-type: image/gif");

$border = 1; //是否要边框 1要:0不要

$how = 4; //验证码位数

$w = $how*15; //图片宽度

$h = 20; //图片高度

$fontsize = 5; //字体大小

$alpha = "abcdefghijkmnopqrstuvwxyz"; //验证码内容1:字母

$number = "023456789"; //验证码内容2:数字

$randcode = ""; //验证码字符串初始化

srand((double)microtime()*1000000); //初始化随机数种子

$im = ImageCreate($w, $h); //创建验证图片

$bgcolor = ImageColorAllocate($im, 255, 255, 255); //设置背景颜色

ImageFill($im, 0, 0, $bgcolor); //填充背景色

if($border)

{

$black = ImageColorAllocate($im, 0, 0, 0); //设置边框颜色

ImageRectangle($im, 0, 0, $w-1, $h-1, $black);//绘制边框

}

for($i=0; $i<$how; $i++)

{

$alpha_or_number = mt_rand(0, 1); //字母还是数字

//   $alpha_or_number = 0;

$str = $alpha_or_number ? $alpha : $number;

$which = mt_rand(0, strlen($str)-1); //取哪个字符

if ( $which == 0 || $which=='o' || $which == "O") {

$i--;

continue;

}

$code = substr($str, $which, 1); //取字符

$j = !$i ? 4 : $j+15; //绘字符位置

$color3 = ImageColorAllocate($im, mt_rand(0,100), mt_rand(0,100), mt_rand(0,100)); //字符随即颜色

ImageChar($im, $fontsize, $j, 3, $code, $color3); //绘字符

$randcode .= $code; //逐位加入验证码字符串

}

for($i=0; $i<$how*40; $i++)//绘背景干扰点

{

$color2 = ImageColorAllocate($im, mt_rand(100,200), mt_rand(100,200), mt_rand(100,200)); //干扰点颜色

ImageSetPixel($im, mt_rand(0,$w), mt_rand(0,$h), $color2); //干扰点

}

//把验证码字符串写入session

// if(!session_id())session_start();

XSession::set('security_code', $randcode);

XSession::set('security_code_time', time());

//$_SESSION['randcode'] = $randcode;

// $_SESSION['randcode_time'] = time();

Imagegif($im);

ImageDestroy($im);

}

访问某个页面时的action中植入如下代码:

$flag = check_ip();

$msg = '';

if(!$flag&&isset($_REQUEST['scode'])&&isset($_SESSION['security_code']) ){

$scode = $_REQUEST['scode'];

if((time()-XSession::get('security_code_time'))>180){

$msg = '验证码超时';

$flag = false;

}

if(!$scode or $scode!=XSession::get('security_code')){

$msg = '验证码输入错误';

$flag = false;

}else{

allow_ip();

$flag=true;

}

}

if(!$flag){

if(isset($_REQUEST['wid'])){

$k = 'wid';

$v = $_REQUEST['wid'];

}elseif(isset($_REQUEST['wname'])){

$k = 'wname';

$v = $_REQUEST['wname'];

}

echo '';

echo $msg;

echo ' 请输入验证码： 换一张? ';

echo '';

exit(0);

}

。

关于IP地址的监测：

function check_ip(){

    $mmc=memcache_init();

    

    if($mmc==false)

        echo "mc init failed\n";

    else

    {

        $ip = $_SERVER["REMOTE_ADDR"];

        if (in_array($ip,array('124.205.90.159'))) {

        return true;

        }

        $key = dechex(ip2long($ip));

        if($v = memcache_get($mmc,$key)){

            if($v>10){

return false;

            }

            memcache_set($mmc,$key,$v+1);

        }else{

            memcache_set($mmc,$key,1,0,60);

        }

    }

    return true;

}

function allow_ip(){

$mmc=memcache_init();

if($mmc==false)

echo "mc init failed\n";

else

{

$ip = $_SERVER["REMOTE_ADDR"];

$key = dechex(ip2long($ip));

memcache_set($mmc,$key,1,0,60);

}

return false;

}