Variable doesn't get defined/updated after function processes? - php

Question

I have coded some alerting system.
But let's not look at the system itself, Let's look at how will the system know that the system really did sent the alert/error to the browsing user.
I have made something so when you randomly go to ?alert=name, without doing any error, it will say 'No errors'.
But if the system makes you go to ?alert=name, it will echo the error.
How I handle posts
function postComment() {
if (!empty($_POST['name']) || !empty($_POST['comment'])) {
$comment = mysql_real_escape_string(htmlentities($_POST['comment']));
$guest = mysql_real_escape_string(htmlentities($_POST['name']));
}
$guestId = 1;
if (empty($guest)) {
$alert = 1;
return header('location: index.php?alert=name');
}
if (empty($comment)) {
$alert = 2;
return header('location: index.php?alert=comment');
}
if (!isset($_COOKIE['alreadyPosted'])) {
mysql_query("INSERT INTO `comments` (`comment_guest`, `guest_id`, `comment`, `comment_date`, `comment_time`) VALUES ('$guest', '$guestId', '$comment', CURDATE(), CURTIME())") or die(mysql_error());
header('Location: index.php?action=sucess');
setcookie(alreadyPosted, $cookieId+1, time() + 60);
} else {
$alert = 3;
header('location: index.php?alert=delay');
}
}
As you see, to check if user really getting that error, I will set $alert to whatever error number it is.
And to check if hes getting the error I will use this:
if (isset($_GET['alert']) == 'name') {
if ($alert == 1) {
echo 'hai';
} else {
echo 'No errors';
}
}
You will probably wonder why I am doing it this way.., well because I use 1 function for post, and my post function goes under the form, and i want the alerts to display up to the form.
Problem:
The variable either doesn't get set to the number that it is supposed to when running the function,
or.. something is blocking it from it.. I don't know..
My guess: Because the check for errors is located up to the postComment function before the variables even get set?
<?php
if (isset($_GET['alert']) == 'name') {
if ($alert == 1) {
echo 'hai';
} else {
echo 'No errors';
}
}
?>
<form action="index.php" method="POST">
<input type="text" name="name" placeholder="Your name here" class="field">
<textarea class="textarea" name="comment" placeholder="Your comment here..."></textarea>
<input type="submit" name="send" class="blue_button" value="Post Comment">
</form><input type="submit" name="" id="margin" class="blue_button" value="See all messages">
<br />
<?php
//Show the comments
showComments();
if (isset($_POST['send'])) {
postComment();
}
if (isset($_GET['delete']) == "comment"){
deleteComment();
}
echo '<br />';
?>
If it is, what is the solution?
Thanks!
Please don't start with the story about mysql_ function, I understood & I will use PDO instead, but I am using mysql_ at the moment for testing purposes

Answer 1

The problem is that you're redirecting on an error, and so the $alert variable does not get carried over.
To fix the problem add the alert type to the $_GET parameters:
function postComment()
{
// ...
if (empty($guest))
{
header('location: index.php?alert=name&alert_type=1');
exit;
}
// ...
}
And then when you check for the error:
if (isset($_GET['alert']) && 'name' == $_GET['alert'])
{
if (isset($_GET['alert_type']) && '1' == $_GET['alert_type'])
{
echo 'hai';
}
else
{
echo 'No errors';
}
}
Note also that I fixed the error here:
isset($_GET['alert']) == 'name'
That doesn't do what I think you think it does. What you want is:
isset($_GET['alert']) && 'name' == $_GET['alert']
(Excuse the order of the comparison; I prefer to have variables on the right for comparisons as it will cause a parse error if you miss a = -- much better than having it run but not do what you expect)

Answer 2

if you are a newbie, you better consider using client side scripting (viz javascript) for validation as using server side validation will simple make the process longer. but as you are facing problems, this might give you the solution.
as you are redirecting the page to index.php?alert=name', so $alert is never set initially when the page loads itself. when you call the function postcomment(), $alert is initiated but immediately destroyed when the system redirects. And as $alert never holds a value when you randomly visit the page, it shows no error.