在我的表单中，我允许用户上传文件到数据库，并将它们发送到另一个页面submission_successful.php，显示"感谢您的提交"。但是我发现当我在提交成功的php文件上点击返回按钮时，它回到了表单，相同的信息仍在并可以重新提交。我想做的是，在点击返回按钮时终止代码或清除用户输入的所有内容。我找到了一些答案，比如使用缓存控制，但有些含糊不清，有些对我没有用。而且我不希望用户在成功页面时返回上传页面。所以我会创建两个按钮，一个是"注销"，一个是"返回上传页面"，如果他们点击返回按钮，它将崩溃。我想显示确认表单重新提交页面。在其他帖子中，他们实际上试图防止"确认表单重新提交"，但出于安全考虑，我想要它。这是我的代码。
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");
}
?>