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Question

I tried figured out how I can get the if empty() for different field input also if captcha is empty or wrong

this is the page of comments.php

    <div class="box">
        <ul>
            <?php 
                $result = $com->index();
                while ($data = $result->fetch_assoc()) {
             ?>
            <li><b><?php echo $data['name']; ?></b>  -  
            <?php echo date('M d, Y', strtotime($data['comment_time'])); ?> - 
        <span class="rating"><?=str_repeat('&#9733;', $data['rating'])?></span><br>  
            <?php echo $data['comment'] ?></li>
            <?php } ?>
        </ul>
    </div><br>
    <center>
        <?php 
            if (isset($_GET['msg'])) {
                $msg = $_GET['msg'];
                echo "<span style='font-size:18px'>".$msg."</span>";
            }
         ?>
    
    <div>
        <form action="post_comment.php" method="post">
        <table>
            <tr>
                <td>Rating:</td>
                <td><ul class="rate-area">
  <input type="radio" id="5-star" name="rating" value="5" /><label for="5-star" title="Amazing">5 stars</label>
  <input type="radio" id="4-star" name="rating" value="4" /><label for="4-star" title="Good">4 stars</label>
  <input type="radio" id="3-star" name="rating" value="3" /><label for="3-star" title="Average">3 stars</label>
  <input type="radio" id="2-star" name="rating" value="2" /><label for="2-star" title="Not Good">2 stars</label>
  <input type="radio" id="1-star" name="rating" value="1" /><label for="1-star" title="Bad">1 star</label>
</ul></td>
            </tr>
            <tr>
                <td>Your Name:<span style='color:red;font-size:20px'>*</span></td>
                <td><input type="text" name="name" placeholder="Please enter your name"></td>
            </tr>
            <tr>
                <td>Comment:<span style='color:red;font-size:20px'>*</span></td>
                <td>
                    <textarea name="comment" placeholder="Please enter your comment"></textarea>
                </td>
            </tr>
            <tr>
                <td> <img src="captcha.php?rand=<?php echo rand(); ?>" id='captchaimg' > </td>
                <td> <a href='javascript: refreshCaptcha();'><img src="refresh.png" width="25px"></a> </td>
            </tr>
            <tr>
                <td colspan="2">Enter the code above here :
                  <input id="6_letters_code" name="6_letters_code" type="text" class="form-control"></td>
            </tr>
            <tr>
                <td></td>
                <td><input type="submit" name="submit" id="contact-submit" value="Post"></td>
                <!-- <td><input style="width: 230px;height: 40px;" type="submit" name="submit" value="Post"></td> -->
            </tr>
        </table>
    </form>
    </div>
    <center>
 <script language='JavaScript' type='text/javascript'>
function refreshCaptcha()
{
    var img = document.images['captchaimg'];
    img.src = img.src.substring(0,img.src.lastIndexOf("?"))+"?rand="+Math.random()*1000;
}
</script>

and this is the post_comments.php

<?php 
    include_once 'controllers/Comment.php';
    $com = new Comment();
    if (isset($_POST['submit'])) {
        $name    = $_POST['name'];
        $comment = $_POST['comment'];
        $rating = $_POST['rating'];
        $capctha = $_POST['6_letters_code'];
        
            if(empty($_SESSION['6_letters_code'] ) ||
              strcmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)
            {
                header('Location: indexcomment.php?msg='.urlencode('The captcha code does not match!'));
            }

        if (empty($name) || empty($comment)) {
                header('Location: indexcomment.php?msg='.urlencode('<span style="color:red;font-size:20px">Field must not be empty !</span>'));
        } else {
            $com->setData($name, $comment, $rating);
            if ($com->create()) {
                header('Location: indexcomment.php?msg='.urlencode('Comment Posting Successfully'));
            }
        }
    }
 ?>

this is the Comment.php

<?php 
    include_once './database/DB.php';
    class Comment
    {
        private $db;
        private $name;
        private $comment;
        private $rating;
        private $table = "tbl_comments";

        public function __construct()
        {
            $this->db = new DB();
        }

        public function setData($name, $comment, $rating)
        {
            $this->name    = $name;
            $this->comment = $comment;
            $this->rating = $rating;
        }

        public function create()
        {
            $query = "INSERT INTO $this->table(name, comment, rating, comment_time) VALUES('$this->name', '$this->comment', '$this->rating', now())";
            $insert_comment = $this->db->insert($query);
            return $insert_comment;
        }

        public function index()
        {
            $query = "SELECT * FROM $this->table ORDER BY id DESC";
            $result = $this->db->select($query);
            return $result;
        }

        public function dateFormat($data)
        {
            date_default_timezone_set('Europe/Berlin');
            $date = date('M j, Y', time());
            return $date;
        }


    }
 ?>

this the DB.php

<?php 
    include_once './config/config.php';
    class DB
    {
        private $host   = DB_HOST;
        private $user   = DB_USER;
        private $pass   = DB_PASS;
        private $dbname = DB_NAME;

        public $link;
        public $error;

        public function __construct()
        {
            $this->connectDB();
        }

        private function connectDB()
        {
            $this->link = new mysqli($this->host, $this->user, $this->pass, $this->dbname);
            if (!$this->link) {
                echo "Connection fail".$this->link->connect_error;
                return false;
            }
        }

        // Insert Data
        public function insert($query)
        {
            $insert_row = $this->link->query($query) or die($this->link->error.__LINE__);
            if ($insert_row) {
                return $insert_row;
            } else {
                return false;
            }
        }

        // Select or Read data
        public function select($query)
        {
            $result = $this->link->query($query) or die($this->link->error.__LINE__);
            if ($result->num_rows > 0) {
                return $result;
            } else {
                return false;
            }
        }
    }
 ?>

and this a config.php

<?php 
    define('DB_HOST', 'localhost');
    define('DB_USER', 'root');
    define('DB_PASS', '****************');
    define('DB_NAME', 'dbcomment');
 ?>

and this is the captcha.php

<?php 

session_start();
//Settings: You can customize the captcha here
$image_width = 280;
$image_height = 40;
$characters_on_image = 6;
$font = './fonts/monofont.ttf';

//The characters that can be used in the CAPTCHA code.
//avoid confusing characters (l 1 and i for example)
$possible_letters = '23456789bcdfghjkmnpqrstvwxyzBCDFGHJKLMNPQRSTVWXYZ';
$random_dots = 30;
$random_lines = 20;
$captcha_text_color="0x142864";
$captcha_noice_color = "0x142864";

$code = '';


$i = 0;
while ($i < $characters_on_image) { 
$code .= substr($possible_letters, mt_rand(0, strlen($possible_letters)-1), 1);
$i++;
}


$font_size = $image_height * .75;
$image = @imagecreate($image_width, $image_height);


/* setting the background, text and noise colours here */
$background_color = imagecolorallocate($image, 255, 255, 255);

$arr_text_color = hexrgb($captcha_text_color);
$text_color = imagecolorallocate($image, $arr_text_color['red'], 
        $arr_text_color['green'], $arr_text_color['blue']);

$arr_noice_color = hexrgb($captcha_noice_color);
$image_noise_color = imagecolorallocate($image, $arr_noice_color['red'], 
        $arr_noice_color['green'], $arr_noice_color['blue']);


/* generating the dots randomly in background */
for( $i=0; $i<$random_dots; $i++ ) {
imagefilledellipse($image, mt_rand(0,$image_width),
 mt_rand(0,$image_height), 2, 3, $image_noise_color);
}


/* generating lines randomly in background of image */
for( $i=0; $i<$random_lines; $i++ ) {
imageline($image, mt_rand(0,$image_width), mt_rand(0,$image_height),
 mt_rand(0,$image_width), mt_rand(0,$image_height), $image_noise_color);
}


/* create a text box and add 6 letters code in it */
$textbox = imagettfbbox($font_size, 0, $font, $code); 
$x = ($image_width - $textbox[4])/2;
$y = ($image_height - $textbox[5])/2;
imagettftext($image, $font_size, 0, $x, $y, $text_color, $font , $code);


/* Show captcha image in the page html page */
header('Content-Type: image/jpeg');// defining the image type to be shown in browser widow
imagejpeg($image);//showing the image
imagedestroy($image);//destroying the image instance
$_SESSION['6_letters_code'] = $code;

function hexrgb ($hexstr)
{
  $int = hexdec($hexstr);

  return array("red" => 0xFF & ($int >> 0x10),
               "green" => 0xFF & ($int >> 0x8),
               "blue" => 0xFF & $int);
}
?>

Somehow I don't get this to work. I been trying to get captcha done when is wrong or empty to show the error notice like "Security code is invalid" and I also tried to get when the name or text is empty that it will show error notice "Name should not be empty" or "Text should not be empty"

I have Debian 10, apache with PHP 8 and mysqli

Answer 1

Assuming that the $_SESSION['6_letters_code'] exists, this condition is omitted but afterwards nothing happens:

            if(empty($_SESSION['6_letters_code'] ) ||
              strcmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0)
            {
                header('Location: indexcomment.php?msg='.urlencode('The captcha code does not match!'));
            }

That means even the details in your code are logical correct, there is a gap in the combination of all the details.

I propose the changes like this (in short removing the last else but executing the code without any condition):

<?php 
    include_once 'controllers/Comment.php';
    $com = new Comment();
    if (isset($_POST['submit'])) {
        $name    = $_POST['name'];
        $comment = $_POST['comment'];
        $rating = $_POST['rating'];
                
        if (empty($name)) {
            header('Location: indexcomment.php?msg='.urlencode('<span style="color:red;font-size:20px">Name must not be empty !</span>'));
            exit;
        }
        if (empty($comment)) {
            header('Location: indexcomment.php?msg='.urlencode('<span style="color:red;font-size:20px">Comment must not be empty !</span>'));
            exit;
        }
        if(empty($_SESSION['6_letters_code']) ||
            strcmp($_SESSION['6_letters_code'], $_POST['6_letters_code']) != 0) {
            header('Location: indexcomment.php?msg='.urlencode('The captcha code does not match!'));
            exit;
        }
        $com->setData($name, $comment, $rating);
        if ($com->create()) {
            header('Location: indexcomment.php?msg='.urlencode('Comment Posting Successfully'));
            exit;
        }
    }
 ?>

I added exit after each redirect to be sure that the script is stopped, as the redirect opens a new site / script.