PHP随机码图片的生成与验证
一般的方法：
checkNumbers.php
<?php
session_start();
if($act == "init")
{
header("content-type: image/png");
//srand(microtime() * 100000);
//$login_check_number = strval(rand("1111","9999"));
$login_check_number = generate_password( 4 );
session_register("login_check_number");
//这里是使用了session来保存校验码.
//当然也可以用cookie
//setcookie("login_check_number",$login_check_number);
//然后将第一行的session_start()删除;
//不推荐使用cookie,因为使用cookie并不能进行安全的验证.
$h_img = imagecreate(40,17);
$c_black = imagecolorallocate($h_img, 0,0,0);
$c_white = imagecolorallocate($h_img, 255,255,255);
imageline($h_img, 1, 1, 350, 25, $c_black);
imagearc($h_img, 200, 15, 20, 20, 35, 190, $c_white);
imagestring($h_img, 5, 2, 1, $login_check_number, $c_white);
imagepng($h_img);
imagedestroy($h_img);
die();
}
function generate_password( $length = 4 ) {
// 密码字符集，可任意添加你需要的字符
$chars = '0123456789';
//$chars = 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
$password = '';
for ( $i = 0; $i < $length; $i++ )
{
// 这里提供两种字符获取方式
// 第一种是使用 substr 截取$chars中的任意一位字符；
// 第二种是取字符数组 $chars 的任意元素
// $password .= substr($chars, mt_rand(0, strlen($chars) - 1), 1);
$password .= $chars[ mt_rand(0, strlen($chars) - 1) ];
}
return $password;
}
?>
调用随机码生成码的登录页面:login.php
<? session_start(); ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>登陆页面</title>
</head>
<?
include_once('./checkNumbers.php');
if(isset($_POST['number']))
{
$number = $_POST['number'];
echo $number.' + ';
if($number != $login_check_number )
{
print("验证码不正确!");
die();
}
else
printf("Successful.");
}
?>
<?php
//应用方法:
//在HTML文件中参加在登陆校验PHP页面中参加以下代码(留心:在参加代码前不能有输出,由于应用了SESSION)
//$number 是你输进的校验码的值
//检验校验码
?>
<body>
<form method="post">
<input type="text" name= "number" maxlength = "4"><img src=checkNumbers.php?act=init>
<input type="submit" name="submit" />
</form>
</body>
</html>
二 验证码产生类
<?php
class ValidationCode{
private $width;
private $height;
private $codeNum;
private $image;
private $disturbColorNum;
private $checkCode;
function __construct($width=80,$height=40,$codeNum=4){
$this->width=$width;
$this->height=$height;
$this->codeNum=$codeNum;
$this->checkCode=$this->createCheckCode();
$number=floor($width*$height/15);
if($number>240-$codeNum){
$this->disturbColorNum=240-$codeNum;
}
else{
$this->disturbColorNum=$codeNum;
}
}
//通过访问该方法向浏览器输出图像
function showImage(){
//创建图片背景
$this->createImage();
//创建干扰元素
$this->setDisturbColor();
//输出文本
$this->outputText();
//输出图像
$this->outputImage();
}
//通过调用该方法获取随机创建的验证码字符串
function getCheckCode(){
return $this->checkCode;
}
//创建背景图片
private function createImage(){
//创建图片资源
$this->image=imagecreatetruecolor($this->width,$this->height);
//随机获得背景色
$backColor=imagecolorallocate($this->image,rand(100,255),rand(120,255),rand(120,255));
//填充背景色
imagefill($this->image,0,0,$backColor);
//设置边框颜色
$border=imagecolorallocate($this->image,0,0,0);
//画出矩形边框
imagerectangle($this->image,0,0,$this->width-1,$this->height-1,$border);
}
//创建干扰元素
private function setDisturbColor(){
//设置像素点
for($i=0;$i<$this->disturbColorNum;$i++){
$color=imagecolorallocate($this->image,rand(0,255),rand(0,255),rand(0,255));
imagesetpixel($this->image,rand(1,$this->width-2),rand(1,$this->height-2),$color);
}
//设置干扰线条，设为10条
for($i=0;$i<10;$i++){
//颜色设置
$color=imagecolorallocate($this->image,rand(2,255),rand(2,244),rand(2,244));
imagearc($this->image,rand(-10,$this->width),rand(-10,$this->height),rand(20,200),rand(30,300),39,34,$color);
}
}
//创建验证字符
private function createCheckCode(){
$code="123456789QWERTYUIPLKJHGFDSAZXCVBNM";
$string='';
for($i=0;$i<$this->codeNum;$i++){
$char=$code{rand(0,strlen($code)-1)};
$string.=$char;
}
return $string;
}
//创建输出的字符
private function outputText(){
for($i=0;$i<$this->codeNum;$i++){
$fontcolor=imagecolorallocate($this->image,rand(0,125),rand(1,124),rand(2,125));
$fontsize=rand(2,5);
$x=floor($this->width/$this->codeNum)*$i+3;
$y=rand(0,$this->height-15);
imagechar($this->image,$fontsize,$x,$y,$this->checkCode{$i},$fontcolor);
}
}
private function outputImage(){
if(imagetypes()&IMG_GIF){
header("Content-Type:image/gif");
imagepng($this->image);
}
else if(imagetypes()&IMG_JPG){
header("Content-Type:image/jpeg");
imagepng($this->image);
}
else if(imagetypes()&IMG_PNG){
header("Content-Type:image/png");
imagepng($this->image);
}
}
function __destruct(){
imagedestroy($this->image);
}
}
?>