Example analysis of a practical PHP verification code class

<?php

header('Content-type:text/html;charset=utf8');

class Code{

  // 验证码个数$number

  protected $number;

  // 验证码类型$codeType

  protected $codeType;

  // 验证码图像宽度$width

  protected $width;

  // 验证码$height

  protected $height;

  // 验证码字符串$code

  protected $code;

  // 图像资源$image

  protected $image;

  public function __construct($number=4,$codeType=0,$height=50,$width=100){

    //初始化自己的成员属性

    $this->number=$number;

    $this->codeType=$codeType;

    $this->width = $width;

    $this->height= $height;

    //生成验证码函数

    $this->code = $this ->createCode();

  }

  public function __get($name){

    if ($name == 'code'){

      return $this->code;

    }

    return false;

  }

  /*获取验证码*/

  public function getCode() {

    return $this->code;

  }

  /*图像资源销毁*/

  public function __destruct(){

    imagedestroy($this->image);

  }

  protected function createCode(){

    //通过你的验证码类型生成验证码

    switch ($this->codeType){

      case 0: //纯数字

        $code = $this->getNumberCode();

        break;

      case 1: //纯字母的

        $code = $this->getCharCode();

        break;

      case 2: //数字和字母混合

        $code = $this->getNumCharCode();

        break;

      default:

        die('不支持此类验证码类型');

    }

    return $code;

  }

  protected function getNumberCode(){

    $str = join('', range(0, 9));

    return substr(str_shuffle($str),0, $this->number);

  }

  protected function getCharCode(){

    $str = join('', range('a', 'z'));

    $str = $str.strtoupper($str);

    return substr(str_shuffle($str),0,$this->number);

  }

  protected function getNumCharCode(){

    $numstr = join('',range(0, 9));

    $str =join('', range('a', 'z'));

    $str =$numstr.$str.strtoupper($str);

    return substr(str_shuffle($str), 0,$this->number);

  }

  protected function createImage(){

    $this->image = imagecreatetruecolor($this->width,

        $this->height);

  }

  protected function fillBack(){

    imagefill($this->image, 0, 0, $this->lightColor());

  }

  /*浅色*/

  protected function lightColor(){

    return imagecolorallocate($this->image, mt_rand(133,255), mt_rand(133,255), mt_rand(133,255));

  }

  /*深色*/

  protected function darkColor(){

    return imagecolorallocate($this->image, mt_rand(0,120), mt_rand(0,120), mt_rand(0,120));

  }

  protected function drawChar(){

    $width = ceil($this->width / $this->number);

    for ($i=0; $i< $this->number;$i++){

      $x = mt_rand($i*$width+5, ($i+1)*$width-10);

      $y = mt_rand(0, $this->height -15);

      imagechar($this->image, 5, $x, $y, $this->code[$i], $this->darkColor());

    }

  }

  protected function drawLine(){

    for ($i=0;$i<5;$i++) {

      imageline($this->image,mt_rand(0,$this->width),mt_rand(0,$this->height),mt_rand(0,$this->width),mt_rand(0,$this->height),$this->darkColor());

    }

  }

  protected function drawDisturb(){

    for ($i=0;$i<150;$i++){

      $x=mt_rand(0, $this->width);

      $y=mt_rand(0, $this->height);

      imagesetpixel($this->image, $x, $y, $this->lightColor());

    }

  }

  protected function show(){

    header('Content-Type:image/png');

    imagepng($this->image);

  }

  public function outImage(){

//     创建画布

    $this->createImage();

//     填充背景色

    $this->fillBack();

//     将验证码字符串花到画布上

    $this->drawChar();

//     添加干扰元素

    $this->drawDisturb();

//     添加线条

    $this->drawLine();

//     输出并显示

    $this->show();

  }

}

<?php

//开启session

session_start();

require_once 'code.php';

$code= new Code(4,1,50,100);

$_SESSION['code']= $code->getCode();

$code->outImage();

<?php

    //开启Session

    session_start();

    //判断是否提交

    if(isset($_POST['dosubmit'])){

      //获取session中的验证码并转为小写

      $sessionCode=strtolower($_SESSION['code']);

      //获取输入的验证码

      $code=strtolower($_POST['code']);

      //判断是否相等

      if($sessionCode==$code){

        echo "<script type=&#39;text/javascript&#39;>alert(&#39;验证码正确!&#39;);</script>";

      }else{

        echo "<script type=&#39;text/javascript&#39;>alert(&#39;验证码错误!&#39;);</script>";

      }

    }

  ?>

  <!DOCTYPE html>

  <html>

    <head>

      <title></title>

      <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"/>

      <style type="text/css">

        *{margin:0px;padding:0px;}

        ul{

          width:400px;

          list-style:none;

          margin:50px auto;

        }

        li{

          padding:12px;

          position:relative;

        }

        label{

          width:80px;

          display:inline-block;

          float:left;

          line-height:30px;

        }

        input[type='text'],input[type='password']{

          height:30px;

        }

        img{

          margin-left:10px;

        }

        input[type="submit"]{

          margin-left:80px;

          padding:5px 10px;

        }

      </style>

    </head>

    <body>

      <form action="login.php" method="post">

        <ul>

          <li>

            <label>用户名：</label>

            <input type="text" name="username"/>

          </li>

          <li>

            <label>密码：</label>

            <input type="password" name="password"/>

          </li>

          <li>

            <label>验证码：</label>

            <input type="text" name="code" size="4" style="float:left"/>

            <img src="test.php" onclick="this.src=&#39;test.php?Math.random()&#39;"/>

          </li>

          <li>

            <input type="submit" value="登录" name="dosubmit"/>

          </li>

        </ul>

      </form>

    </body>

  </html>