创建 PHP 文本验证码

清疚 2023-09-27 08:10 44阅读 0赞

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。

<?php
    
    /* 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。

<?php
    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 = "<span style='color:red'>The Validation code does not match!</span>"; // Captcha verification is incorrect.
        } else {// Captcha verification is Correct. Final Code Execute here!
            $msg = "<span style='color:green'>The Validation code has been matched.</span>";
        }
    }
    ?>
    <!doctype html>
    <html>
        <head>
            <meta charset="utf-8">
            <title>PHP Secure text Captcha.</title>
            <link href="./css/style.css" rel="stylesheet">
            <script type='text/javascript'>
                function refreshCaptcha() {
                    var img = document.images['captchaimg'];
                    img.src = img.src.substring(0, img.src.lastIndexOf("?")) + "?rand=" + Math.random() * 1000;
                }
            </script>
        </head>
        <body>
            <div id="frame0">
                <center> <h1>PHP Secure Text Captcha Demo.</h1>
                    <p>More tutorials <a href="https://tutorialswebsite.com">www.tutorialswebsite.com</a></p></center>
            </div>
            <br>
    
            <form action="" method="post" name="form1" id="form1" >
                <table width="400" border="0" align="center" cellpadding="5" cellspacing="1" class="table">
    <?php if (isset($msg)) { ?>
                        <tr>
                            <td colspan="2" align="center" valign="top"><?php echo $msg; ?></td>
                        </tr>
    <?php } ?>
                    <tr>
                        <td align="right" valign="top"> Validation code:</td>
                        <td><img src="captcha.php?rand=<?php echo rand(); ?>" id='captchaimg'><br>
                            <label for='message'>Enter the code above here :</label>
                            <br>
                            <input id="captcha_code" name="captcha_code" type="text">
                            <br>
                            Can't read the image? click <a href='javascript: refreshCaptcha();'>here</a> to refresh.</td>
                    </tr>
                    <tr>
                        <td> </td>
                        <td><input name="Submit" type="submit" onclick="return validate();" value="Submit" class="button1"></td>
                    </tr>
                </table>
            </form>
        </body>
    </html>

### captcha.php ###

该文件用于创建验证码图像。在这个文件中，我们包含**“phpcaptchaClass.php”**文件并创建一个phpcaptchaClass对象。  
phpcaptcha()：-此函数根据参数创建带有文本和线条或噪声的图像。

<?php
    
    session_start();
    include("./phpcaptchaClass.php");
    
    /* create class object */
    $phptextObj = new phpcaptchaClass();
    /* phptext function to genrate image with text */
    $phptextObj->phpcaptcha('#000', '#fff', 120, 40, 10, 25);
    ?>

### 结论 ###

在示例脚本中，静态图像显示在 3D 图像库中。