Global/SESSION PHP Array/Variable without content - php

Question

I have a huge problem which I can't seem to fix. I got 2 files. insertDB.php(for writing content into my database) & mail.php(for sending me a mail if something got written into databse). Because I don't want the mail stuff in the same file as the SQL-Statements, I created the mail.php file.
Now I want to pass Variables or an Array from insertDB to mail. It works in every other file I'm using but it's not working here.
<?php
//insertDB.php
Session_Start();
include 'dbconnect.php';
$login = $_SESSION['login'];
$num = $_mysqli->real_escape_string($_POST['num']);
$date = $_mysqli->real_escape_string($_POST['date']);
$user = $_mysqli->real_escape_string($_POST['user']);
$program = $_mysqli->real_escape_string($_POST['program']);
$name = $_mysqli->real_escape_string($_POST['name']);
$path = $_mysqli->real_escape_string($_POST['path']);
$mailData = [$num, $date, $user, $program, $name, $path];
$_SESSION['mailData'] = $mailData;
// var_dump($_SESSION['mailData']); <- outputs array WITH content
$insert = "INSERT INTO Zeichnungen (Num, Date, User, Program, Name, Path, Info, Leer)
VALUES ('$num', '$date', '$user', '$program', '$name', '$path', '', '$login')";
if ($_result = $_mysqli->query($insert)) {
header('Location: mail.php');
}
?>
<?php
//mail.php
Session_Start();
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
use PHPMailer\PHPMailer\SMTP;
include '/opt/composer/vendor/autoload.php';
include 'insertDB.php';
$login = $_SESSION['login'];
var_dump($_SESSION['mailData']);
?>
/* Output I see in Browser from mail.php -> var_dump($_SESSION['mailData']); : */
array(6) { [0]=> string(0) "" [1]=> string(0) "" [2]=> string(0) "" [3]=> string(0) "" [4]=> string(0) "" [5]=> string(0) "" }
What is the problem? Why does it have no content but the 6 keys?
Any help appreciated.

Answer 1

Looking at the code, there is nothing obvious to me that can cause var_dump() to print 6 empty strings. Running the provided code does not reproduce your problem (despite unnecessarily calling start_session() again, but that has no effect other than a warning).
This is difficult to debug this way. Don't use the session for this if this data does not survive through multiple requests. If you don't want to use classes, at least pass the data to functions with one responsibility. Using the session to store these variables is not a good practice. It is unnecessary global state and will eventually make this code even more difficult to follow and debug.
You have several examples in http://php.net/manual/en/functions.user-defined.php. Define the functions in one file and note that you must include that file before being able to use them. Do not mix concerns, ie: your mail function should not set HTTP headers, and your database function should not access the $_SESSION or $_POST variables.
For example, in insertIntoDb.php (less fields for clarity) and using functions:
<?php
// ... (necessary mysqli includes, etc.)
function insertIntoDB(array $formData) {
// we escape the data here, this escaping is DB specific.
$num = $_mysqli->real_escape_string($formData['num']);
$date = $_mysqli->real_escape_string($formData['date']);
$login = $formData['login'];
$insert = "
INSERT INTO SomeTable (Num, Date, Login)
VALUES ('$num', '$date', '$login');
";
// it's better not to have other side effects here
// if everything goes right, we just continue
$result = $_mysqli->query($insert);
if (!$result) {
die("Database error");
}
}
In your mail.php file:
<?php
include 'insertIntoDb.php';
include 'sendEmail.php';
// we read the POST and other values here
// constructing an associative array is an
// option if not using objects.
$formData = [
'num' => $_POST['num'],
'date' => $_POST['date'],
'login' => $_SESSION['login'],
];
// using the functions
insertIntoDb($formData);
sendEmail($formData); // defined in sendEmail.php, not in example.
// this point is reached when everything works,
// no need to control flow...
header('Location: success.php'); // perhaps "thanks" message.

Answer 2

as many have said, the code is clean and should work. The other possible culprit is the following line
header('Location: mail.php');
The php function header() clears all GETs & POSTs when client leaves current page.
Instead make mail.php a function then include mail.php in insertDB.php
NB: try to adopt OOP coding particulary when dealing with PHP