I'm making something similar a captha, the not working part is the IF, under if(isset($_POST['submit'])), that always returns false. I think. Tried a lot ways with no luck... Anyway, I have followed this solution https://stackoverflow.com/a/21504949/4167976 without success.
Here is my test php and html:
<?php
session_start();
$char = "abcdefghijklmnopqrstuvwxyz1234567890";
$code = $char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)];
$_SESSION["testcode"] = $code;
echo $_SESSION["testcode"]."<br>"; // echo here only for testing
if(isset($_POST['submit'])) {
$code1 = mb_substr($_POST['fullcode'], 0, 5);
$code2 = mb_substr($_POST['fullcode'], -6);
if ($code2 == $_SESSION["testcode"])
{echo "The code is correct!";}
else
{echo "Wrong code!";}
// unset($_SESSION['testcode']); // ???
}
?>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body>
<form action="<?php echo $_SERVER['PHP_SELF']; ?>" method="post">
<input type="text" name="fullcode">
<input type="Submit" name="submit" value="Submit!">
</form>
</body>
</html>
Please, tell me what and where I'm wrong... Thanks! :)
EDIT:
<?php
session_start();
if (!isset($_SESSION["testcode"])) {
$char = "abcdefghijklmnopqrstuvwxyz1234567890";
$code = $char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)];
$_SESSION["testcode"] = $code;
}
if(isset($_POST['submit'])) {
$code1 = mb_substr($_POST['fullcode'], 0, 5);
$code2 = mb_substr($_POST['fullcode'], -6);
if ($code2 === $_SESSION["testcode"])
{echo "The code is correct!<br>";}
else
{echo "Wrong code!<br>";}
unset($_SESSION['testcode']);
$char = "abcdefghijklmnopqrstuvwxyz1234567890";
$code = $char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)];
$_SESSION["testcode"] = $code;
}
?>
Finally, get a new code IF the condition is false!
<?php
session_start();
// first request.
// if not set session 'testcode' and set it, else do nothing.
// prevent session be covered.
if (!isset($_SESSION["testcode"])) {
reFreshCode();
}
if(isset($_POST['submit'])) {
$code1 = mb_substr($_POST['fullcode'], 0, 5);
$code2 = mb_substr($_POST['fullcode'], -6);
if ($code2 == $_SESSION["testcode"])
echo "The code is correct!";
else {
// get a new code IF the condition is false!
echo "Wrong code!";
echo “new code：”.reFreshCode();
}
}
function reFreshCode() {
$char = "abcdefghijklmnopqrstuvwxyz1234567890";
$code = $char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)].$char[rand(0,35)];
return $_SESSION["testcode"] = $code;
}