On my form , i allow users to upload files to the database and i send them to another page, which is submission_successful.php, that says "Thank You for Submitting". But i noticed that when i hit the back button on the submission successful php file, it goes back to the form and the same information is there and allows another submission. What i want to do is kill the code, upon hitting back button, or clear everything that was inputted by the user. I found a couple of answers around like using cache control but, some were vague and others didn't work for me. And plus i don't want the user going back to the upload page when they're on the success page. So thats why i will create 2 buttons for "logout" or "go back to upload page" and if they hit back button, it will crash. I want to show the Confirm Form Resubmission page. In other post they are trying to actually prevent the "Confirm Form Resubmission" but i would like to have it for security. Here is my code
developerUpload.php
<?php
session_start();
if(array_key_exists("invalid", $_GET)){
echo '<br><h3 style="color:red;">File(s) were already submitted! Please re-name file or select a different file...</h3>';
}
if(isset($_COOKIE['username'])){
if($_SERVER['REQUEST_METHOD'] =="POST"){
$price = addslashes(trim($_POST['price']));
$description = addslashes(trim($_POST['description']));
if(!empty($price) && !empty($description)){
$userid = $_SESSION['id'];
$username = $_SESSION['username'];
echo '<br>'.$userid;
$pack_id = rand();
//Check file 1
if($_FILES['file1']['error'] !== UPLOAD_ERR_OK){
$file1 = null;
}else{
$target1 = "devFiles/";
$target_file1 = addslashes(trim($target1 . basename($_FILES["file1"]["name"])));
$file1 = addslashes(trim($_FILES['file1']['tmp_name']));
}
//Check file 2
if($_FILES['file2']['error'] !== UPLOAD_ERR_OK){
$file2 = null;
}else{
$target2 = "devFiles/";
$target_file2 = addslashes(trim($target2 . basename($_FILES["file2"]["name"])));
$file2 = addslashes(trim($_FILES['file2']['tmp_name']));
}
//Check file 3
if($_FILES['file3']['error'] !== UPLOAD_ERR_OK){
$file3 = null;
}else{
$target3 = "devFiles/";
$target_file3 = addslashes(trim($target3 . basename($_FILES["file3"]["name"])));
$file3 = addslashes(trim($_FILES['file3']['tmp_name']));
}
//Check file 4
if($_FILES['file4']['error'] !== UPLOAD_ERR_OK){
$file4 = null;
}else{
$target4 = "devFiles/";
$target_file4 = addslashes(trim($target4 . basename($_FILES["file4"]["name"])));
$file4 = addslashes(trim($_FILES['file4']['tmp_name']));
}
//Check file 5
if($_FILES['file5']['error'] !== UPLOAD_ERR_OK){
$file5 = null;
}else{
$target5 = "devFiles/";
$target_file5 = addslashes(trim($target5 . basename($_FILES["file5"]["name"])));
$file5 = addslashes(trim($_FILES['file5']['tmp_name']));
}
//Check video
if($_FILES['video']['error'] !== UPLOAD_ERR_OK){
$video = null;
$videoName = null;
}else{
$target = "devFiles/";
$target_file = addslashes(trim($target . basename($_FILES["video"]["name"])));
$video = addslashes(trim($_FILES['video']['tmp_name']));
$videoName = addslashes(trim($_FILES['video']['name']));
}
if(file_exists($target_file1)
or file_exists($target_file2)
or file_exists($target_file3)
or file_exists($target_file4)
or file_exists($target_file5)
or file_exists($target_file)){
header("Location: developerUpload.php?invalid");
exit;
}
if(move_uploaded_file($_FILES["file1"]["tmp_name"], $target_file1)
&& move_uploaded_file($_FILES["file2"]["tmp_name"], $target_file2)
&& move_uploaded_file($_FILES["file3"]["tmp_name"], $target_file3)
&& move_uploaded_file($_FILES["file4"]["tmp_name"], $target_file4)
&& move_uploaded_file($_FILES["file5"]["tmp_name"], $target_file5)
&& move_uploaded_file($_FILES["video"]["tmp_name"], $target_file)){
try{
// new php data object
$handler = new PDO('mysql:host=127.0.0.1;dbname=magicsever', 'root', '');
//ATTR_ERRMODE set to exception
$handler->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}catch(PDOException $e){
die("There was an error connecting to the database");
}
header("Location: submission_successful.php?");
die();
}
}else{
echo '<br><h1 style="color:red;">VALUES MISSING!</h1>';
}
}
}else {
header("Location: developerLogin.php");
}
?>
submission_successful.php
<?php
session_start();
if(array_key_exists("invalid", $_GET)){
header("Location: developerUpload.php?invalid");
}
if(isset($_COOKIE['username'])){
echo '<br><h1 style="color:red; text_align:center;">Thank You for Submitting!</h1>';
}else{
header("Location: developerLogin.php");
}
?>