PHP Text Captcha 是由免费的验证码脚本生成的文本图像。它用于保护您的登录表单、注册表单或任何表单免受垃圾邮件、滥用和黑客攻击。

在本文中，我们将学习如何在没有 google captcha API 的情况下创建 PHP Text Captacha。PHP Text Captcha 是用于创建复杂图像的开源脚本。

PHP文本验证码的特点：

• 代码结构很小。
• phpTextClass 用于创建验证码图像
• 代码是完全可定制的
• 带有随机线条和噪音的安全功能
• 防止垃圾邮件发送者和滥用脚本。
• 消除从随机黑客脚本中破解信息的可能性。

phpcaptchaClass.php

在这个文件中，我们创建了一个 phpcaptcha 类、hexTo RGB 和 ImageTTFCenter 函数来创建文本验证码的 imgae。

 
/* phpcaptcha class, version 1.0
  created by www.tutorialswebsite.com (Pradeep Maurya)
  october 5, 2017
 */
 
class phpcaptchaClass {
 
    public function phptext($text, $textColor, $backgroundColor = '', $fontSize, $imgWidth, $imgHeight, $dir, $fileName) {
        /* settings */
        $font = realpath(".") . '/monofont.ttf'; /* define font */
        $textColor = $this->hexToRGB($textColor);
 
        $im = imagecreatetruecolor($imgWidth, $imgHeight);
        $textColor = imagecolorallocate($im, $textColor['r'], $textColor['g'], $textColor['b']);
 
        if ($backgroundColor == '') {/* select random color */
            $colorCode = array('#56aad8', '#61c4a8', '#d3ab92');
            $backgroundColor = $this->hexToRGB($colorCode[rand(0, count($colorCode) - 1)]);
            $backgroundColor = imagecolorallocate($im, $backgroundColor['r'], $backgroundColor['g'], $backgroundColor['b']);
        } else {/* select background color as provided */
            $backgroundColor = $this->hexToRGB($backgroundColor);
            $backgroundColor = imagecolorallocate($im, $backgroundColor['r'], $backgroundColor['g'], $backgroundColor['b']);
        }
 
        imagefill($im, 0, 0, $backgroundColor);
        list($x, $y) = $this->ImageTTFCenter($im, $text, $font, $fontSize);
        imagettftext($im, $fontSize, 0, $x, $y, $textColor, $font, $text);
        if (imagejpeg($im, $dir . $fileName, 90)) {/* save image as JPG */
            return json_encode(array('status' => TRUE, 'image' => $dir . $fileName));
            imagedestroy($im);
        }
    }
 
    public function phpcaptcha($textColor, $backgroundColor, $imgWidth, $imgHeight, $noiceLines = 0, $noiceDots = 0, $noiceColor = '#162453') {
        /* Settings */
        $text = $this->random();
        $font = realpath(".") . '/monofont.ttf'; /* define font */
        $textColor = $this->hexToRGB($textColor);
        $fontSize = $imgHeight * 0.75;
 
        $im = imagecreatetruecolor($imgWidth, $imgHeight);
        $textColor = imagecolorallocate($im, $textColor['r'], $textColor['g'], $textColor['b']);
 
        $backgroundColor = $this->hexToRGB($backgroundColor);
        $backgroundColor = imagecolorallocate($im, $backgroundColor['r'], $backgroundColor['g'], $backgroundColor['b']);
 
        /* generating lines randomly in background of image */
        if ($noiceLines > 0) {
            $noiceColor = $this->hexToRGB($noiceColor);
            $noiceColor = imagecolorallocate($im, $noiceColor['r'], $noiceColor['g'], $noiceColor['b']);
            for ($i = 0; $i < $noiceLines; $i++) {
                imageline($im, mt_rand(0, $imgWidth), mt_rand(0, $imgHeight),
                        mt_rand(0, $imgWidth), mt_rand(0, $imgHeight), $noiceColor);
            }
        }
 
        if ($noiceDots > 0) {/* generating the dots randomly in background */
            for ($i = 0; $i < $noiceDots; $i++) {
                imagefilledellipse($im, mt_rand(0, $imgWidth),
                        mt_rand(0, $imgHeight), 3, 3, $textColor);
            }
        }
 
        imagefill($im, 0, 0, $backgroundColor);
        list($x, $y) = $this->ImageTTFCenter($im, $text, $font, $fontSize);
        imagettftext($im, $fontSize, 0, $x, $y, $textColor, $font, $text);
 
        imagejpeg($im, NULL, 90); /* Showing image */
        header('Content-Type: image/jpeg'); /* defining the image type to be shown in browser widow */
        imagedestroy($im); /* Destroying image instance */
        if (isset($_SESSION)) {
            $_SESSION['captcha_code'] = $text; /* set random text in session for captcha validation */
        }
    }
 
    /* for random string */
 
    protected function random($characters = 6, $letters = '23456789bcdfghjkmnpqrstvwxyz') {
        $str = '';
        for ($i = 0; $i < $characters; $i++) {
            $str .= substr($letters, mt_rand(0, strlen($letters) - 1), 1);
        }
        return $str;
    }
 
    /* function to convert hex value to rgb array */
 
    protected function hexToRGB($colour) {
        if ($colour[0] == '#') {
            $colour = substr($colour, 1);
        }
        if (strlen($colour) == 6) {
            list( $r, $g, $b ) = array($colour[0] . $colour[1], $colour[2] . $colour[3], $colour[4] . $colour[5]);
        } elseif (strlen($colour) == 3) {
            list( $r, $g, $b ) = array($colour[0] . $colour[0], $colour[1] . $colour[1], $colour[2] . $colour[2]);
        } else {
            return false;
        }
        $r = hexdec($r);
        $g = hexdec($g);
        $b = hexdec($b);
        return array('r' => $r, 'g' => $g, 'b' => $b);
    }
 
    /* function to get center position on image */
 
    protected function ImageTTFCenter($image, $text, $font, $size, $angle = 8) {
        $xi = imagesx($image);
        $yi = imagesy($image);
        $box = imagettfbbox($size, $angle, $font, $text);
        $xr = abs(max($box[2], $box[4]));
        $yr = abs(max($box[5], $box[7]));
        $x = intval(($xi - $xr) / 2);
        $y = intval(($yi + $yr) / 2);
        return array($x, $y);
    }
 
}
 
?>

index.php

该文件用于创建表单数据并用于在提交表单后验证验证码图像。

session_start();
 
if (isset($_POST['Submit'])) {
    // code for check server side validation
    if (empty($_SESSION['captcha_code']) || strcasecmp($_SESSION['captcha_code'], $_POST['captcha_code']) != 0) {
        $msg = "The Validation code does not match!"; // Captcha verification is incorrect.
    } else {// Captcha verification is Correct. Final Code Execute here!
        $msg = "The Validation code has been matched.";
    }
}
?>
    
        "utf-8">
        
        "./css/style.css" rel="stylesheet">
        
    
    
        
"frame0">
             
PHP Secure Text Captcha Demo.
                
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