Thinkphp3.2实用篇之计算型验证码示例

是不是觉得普通的验证码已经没办法满足，接下来介绍如何将tp现有的验证码改为计算型验证码：

首先找到：thinkphp\library\think\verify.class.php

在其中加入以下代码：

public function entry_add($id = '') {
    $this->length='3';
    // 图片宽(px)
    $this->imagew || $this->imagew = $this->length*$this->fontsize*1.5 + $this->length*$this->fontsize/2; 
    // 图片高(px)
    $this->imageh || $this->imageh = $this->fontsize * 2.5;
    // 建立一幅 $this->imagew x $this->imageh 的图像
    $this->_image = imagecreate($this->imagew, $this->imageh); 
    // 设置背景   
    imagecolorallocate($this->_image, $this->bg[0], $this->bg[1], $this->bg[2]); 

    // 验证码字体随机颜色
    $this->_color = imagecolorallocate($this->_image, mt_rand(1,150), mt_rand(1,150), mt_rand(1,150));
    // 验证码使用随机字体
    $ttfpath = dirname(__file__) . '/verify/' . ($this->usezh ? 'zhttfs' : 'ttfs') . '/';

    if(empty($this->fontttf)){
      $dir = dir($ttfpath);
      $ttfs = array();    
      while (false !== ($file = $dir->read())) {
        if($file[0] != '.' && substr($file, -4) == '.ttf') {
          $ttfs[] = $file;
        }
      }
      $dir->close();
      $this->fontttf = $ttfs[array_rand($ttfs)];
    } 
    $this->fontttf = $ttfpath . $this->fontttf;
    
    if($this->useimgbg) {
      $this->_background();
    }
    
    if ($this->usenoise) {
      // 绘杂点
      $this->_writenoise();
    }
    if ($this->usecurve) {
      // 绘干扰线
      $this->_writecurve();
    }
    
    // 绘验证码
    $code = array(); // 验证码
    $symbol=array('+','-');
    $codenx = 0; // 验证码第n个字符的左边距
    $now_symbol=$symbol[rand(0,1)];
    for ($i = 0; $i<$this->length; $i++) {
      if($i==1){
        $code[$i] = $now_symbol;
        $codenx += mt_rand($this->fontsize*1.2, $this->fontsize*1.6);
        imagettftext($this->_image, $this->fontsize,0, $codenx, $this->fontsize*1.6, $this->_color, $ttfpath.'2.ttf', $code[$i]);
      }
      else{
        $code[$i] = $this->codeset[mt_rand(0, strlen($this->codeset)-1)];
        $codenx += mt_rand($this->fontsize*1.2, $this->fontsize*1.6);
        imagettftext($this->_image, $this->fontsize, mt_rand(-40, 40), $codenx, $this->fontsize*1.6, $this->_color, $this->fontttf, $code[$i]);
      } 
    }
    
    // 保存验证码
    $key    =  $this->authcode($this->sekey);
    $str=implode('', $code);
    eval("\$re=$str;");
    $code    =  $this->authcode($re);
    $secode   =  array();
    $secode['verify_code'] = $code; // 把校验码保存到session
    $secode['verify_time'] = now_time; // 验证码创建时间
    session($key.$id, $secode);
            
    header('cache-control: private, max-age=0, no-store, no-cache, must-revalidate');
    header('cache-control: post-check=0, pre-check=0', false);    
    header('pragma: no-cache');
    header("content-type: image/png");

    // 输出图像
    imagepng($this->_image);
    imagedestroy($this->_image);
  }

public function check_add($code, $id = '') {
    $key = $this->authcode($this->sekey).$id;
    // 验证码不能为空
    $secode = session($key);
    if($code===false || empty($secode)) {
      return false;
    }
    //验证码是否是数字
    if(!is_numeric($code)) {
      return false;
    }
    // session 过期
    if(now_time - $secode['verify_time'] > $this->expire) {
      session($key, null);
      return false;
    }
    if($this->authcode($code) == $secode['verify_code']) {
      $this->reset && session($key, null);
      return true;
    }
    return false;
  }

生成方法：

public function verify(){
    import('org.util.verify');
    $verify = new verify();
    $verify->usenoise = true;
    $verify->codeset = '0123456789';
    $verify->usecurve = false;
    $verify->entry_add();
  }

验证方法：

 if (!check_verify($verify,'','add')) {
      $this->error('验证码错误！');
      return;
    }

 调用的公共方法：

 // 检测输入的验证码是否正确，$code为用户输入的验证码字符串
function check_verify($code, $id = '',$type=''){
  import('org.util.verify');
  $verify = new verify();
  if($type='add'){
    return $verify->check_add($code, $id);
  }
  else{
    return $verify->check($code, $id);
  }
}

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