Example of Captcha verification code class implemented in PHP, captcha verification code_PHP tutorial

Captcha verification code class instance implemented by php, captcha verification code

The example in this article describes the Captcha verification code class implemented in PHP, which is extremely widely used in PHP programming. Share it with everyone for your reference. The specific method is as follows:

The verification code files are as follows:

<&#63;php
/** Captcha 验证码类
* Date: 2011-02-19
* Author: fdipzone
*/

class Captcha{ //class start

 private $sname = '';

 public function __construct($sname=''){ // $sname captcha session name
 $this->sname = $sname==''&#63; 'm_captcha' : $sname;
 }

 /** 生成验证码图片
 * @param int $length 验证码长度
 * @param Array $param 參數
 * @return IMG
 */
 public function create($length=4,$param=array()){
 Header("Content-type: image/PNG");
 $authnum = $this->random($length); //生成验证码字符.
 
 $width = isset($param['width'])&#63; $param['width'] : 13; //文字宽度
 $height = isset($param['height'])&#63; $param['height'] : 18; //文字高度
 $pnum = isset($param['pnum'])&#63; $param['pnum'] : 100; //干扰象素个数
 $lnum = isset($param['lnum'])&#63; $param['lnum'] : 2; //干扰线条数

 $this->captcha_session($this->sname,$authnum);  //将随机数写入session

 $pw = $width*$length+10;
 $ph = $height+6;
  
 $im = imagecreate($pw,$ph);   //imagecreate() 新建图像，大小为 x_size 和 y_size 的空白图像。
 $black = ImageColorAllocate($im, 238,238,238); //设置背景颜色
 
 $values = array(
  mt_rand(0,$pw), mt_rand(0,$ph),
  mt_rand(0,$pw), mt_rand(0,$ph),
  mt_rand(0,$pw), mt_rand(0,$ph),
  mt_rand(0,$pw), mt_rand(0,$ph),
  mt_rand(0,$pw), mt_rand(0,$ph),
  mt_rand(0,$pw), mt_rand(0,$ph)
 );
 imagefilledpolygon($im, $values, 6, ImageColorAllocate($im, mt_rand(170,255),mt_rand(200,255),mt_rand(210,255))); //设置干扰多边形底图
 
 /* 文字 */
 for ($i = 0; $i < strlen($authnum); $i++){
  $font = ImageColorAllocate($im, mt_rand(0,50),mt_rand(0,150),mt_rand(0,200));//设置文字颜色
  $x = $i/$length * $pw + rand(1, 6); //设置随机X坐标
  $y = rand(1, $ph/3);   //设置随机Y坐标
  imagestring($im, mt_rand(4,6), $x, $y, substr($authnum,$i,1), $font); 
 }

 /* 加入干扰象素 */
 for($i=0; $i<$pnum; $i++){
  $dist = ImageColorAllocate($im, mt_rand(0,255),mt_rand(0,255),mt_rand(0,255)); //设置杂点颜色
  imagesetpixel($im, mt_rand(0,$pw) , mt_rand(0,$ph) , $dist); 
 } 

 /* 加入干扰线 */
 for($i=0; $i<$lnum; $i++){
  $dist = ImageColorAllocate($im, mt_rand(50,255),mt_rand(150,255),mt_rand(200,255)); //设置线颜色
  imageline($im,mt_rand(0,$pw),mt_rand(0,$ph),mt_rand(0,$pw),mt_rand(0,$ph),$dist);
 }

 ImagePNG($im); //以 PNG 格式将图像输出到浏览器或文件
 ImageDestroy($im); //销毁一图像
 }

 /** 检查验证码
 * @param String $captcha 验证码
 * @param int $flag 验证成功后 0:不清除session 1:清除session
 * @return boolean
 */ 
 public function check($captcha,$flag=1){
 if(empty($captcha)){
  return false;
 }else{
  if(strtoupper($captcha)==$this->captcha_session($this->sname)){ //检测验证码
  if($flag==1){
   $this->captcha_session($this->sname,'');
  }
  return true;
  }else{
  return false;
  }
 }
 }

 /* 产生随机数函数
 * @param int $length 需要随机生成的字符串數
 * @return String
 */
 private function random($length){
 $hash = '';
 $chars = 'ABCDEFGHIJKLMNPQRSTUVWXYZ23456789';
 $max = strlen($chars) - 1;
 for($i = 0; $i < $length; $i++) {
  $hash .= $chars[mt_rand(0, $max)];
 }
 return $hash;
 }

 /** 验证码session处理方法
 * @param String $name captcha session name
 * @param String $value
 * @return String
 */
 private function captcha_session($name,$value=null){
 if(isset($value)){
  if($value!==''){
  $_SESSION[$name] = $value;
  }else{
  unset($_SESSION[$name]);
  }
 }else{
  return isset($_SESSION[$name])&#63; $_SESSION[$name] : '';
 }
 }
} // class end
&#63;>

The demo sample program is as follows:

<&#63;php 
  session_start(); 
  require_once('Captcha.class.php'); 
 
  $obj = new Captcha($sname);   # 创建Captcha类对象 
                  # $sname为保存captcha的session name,可留空,留空則为'm_captcha' 
 
  $obj->create($length,$param);  #创建Captcha并输出图片 
                  # $length为Captcha长度，可留空，默认为4 
                  /* $param = array( 
                      'width' => 13    captcha 字符宽度 
                      'height' => 18    captcha 字符高度 
                      'pnum' => 100    干扰点个数
                      'lnum' => 2     干扰线条数 
                      ) 
                      可留空 
                  */ 
  $obj->check($captcha,$flag); # 检查用户输入的验证码是否正确，true or false 
                  # $captcha为用户输入的验证码,必填 
                  # $flag 可留空，默认为1  
                  #    1:当验证成功后自动清除captcha session 
                  #    0:挡验证成功后不清除captcha session,用于ajax检查 
&#63;>

I believe that what is described in this article has certain reference value for everyone’s learning of PHP programming.

Can anyone give an example of Zend_Captcha generating verification code - PHP framework development

I don’t understand why zend made the default verification code so difficult to read, it’s almost impossible for people to recognize it.

php registration page verification code verification code The code is as follows:

You have to judge whether the verification code you filled in is consistent with the verification code you saved before

if($_POST["captcha"]!=$_SESSION["captcha"] )
{
echo "Verification code error";
}

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