Redirect in an if block works even though condition not satisfied?

[mrob]

Hi,

I am trying to redirect when a certain condition is satisfied. Did a search for similar problem - can't find any.

The page seems to redirect even when the condition in the if statement has not been satisfied. Even though the if statement works if I change the content of the block to some simple echo statement.Here's the code:

if ($num >= count($_SESSION['questions'])) {header ('Location: correct.php');}

-redirects when $num=1 and count=6

The following works fine, it waits til the condition is satisfied:

if ($num >= count($_SESSION['ceisteanna'])) {echo count($_SESSION['ceisteanna')."<br>$num";}

I have a similar statement earlier in the script that works fine:

if (!isset($_SESSION['ceisteanna'])){header('Location: setup_quiz.php');}

Any pointers in the right direction, manual on header doesn't give me any clues?

Thanks for your time,
mrob

[laserlight]

Let's try:

<?php
if (1 >= 6)
	header("Location: http://www.example.com");
else
	echo 'It works fine so far';
?>

Once you're satisfied this works fine, double check your code.
Is there another header() call somewhere?
When you ran your check, did you mix up $num and count($_SESSION['questions']) since only the associated values were output?

[mrob]

Thanks Laserlight.

Tried the snippet with the actual numbers - works fine.

did you mix up $num and count($_SESSION['questions']) since only the associated values were output?

Not sure what you mean by only associated values - here's what I've tried to see what was getting into the if statement:

This works and echos 1 for $num and 6 for $count and doesn't redirect.

$count=count($_SESSION['ceisteanna']);
echo "num=$num<br>count=$count";
if ($num >= $count) {header ("Location: correct.php?num=$num&count=$count");}

This however, redirects under the same conditions:

$count=count($_SESSION['ceisteanna']);
//echo "num=$num<br>count=$count";
if ($num >= $count) {header ("Location: correct.php?num=$num&count=$count");}

And the script I direct to echos the values 1 for $num and 0 for $count?! Here it is:

$content="<h1>Ceartú</h1> <p><br>num=".$_GET['num']."<br>count=".$_GET['count']."</p>";

Other headers? Yes.

1. The first is in an included file to check if logged in properly and redirects to login page. Works fine.
2. The next is the one I mentioned in my original post - redirects to setup_quiz to fill the session with questions in case the page is accessed by mistake. At the moment setup_quiz add questions to session and redirects back to the script I'm having trouble with.This also works fine if the troublesome if statement is commented out.
   3 Last header - the one giving me trouble.

Thanks,
mrob

[laserlight]

Fascinating, I dont recall ever coming across such a case before.
It almost looks as if the echo statement really makes a difference.
What's your version of PHP, the operating system, webserver, and do you have error reporting set to E_ALL?
Can you find (and provide) the smallest example of a script that displays this problem?

[mrob]

I'm using:
php 4.2.3
Apache 1.3.27
Os: Windows XP Home Edition
Packaged and setup by phpdev 4.2.3 from firepages.com.au
Errors: error_reporting = E_ALL & ~E_NOTICE
display_errors = On
display_startup_errors = On
log_errors = On
error_log = errors.txt
track_errors = Off

I put together two smaller examples one of which has the problem and another which works fine. The problem seems to be caused by my redirecting to one page, assigning values to session array, and then redirecting back again, though I can't see why this causes difficulty, nor why the later echo statement affects the action of the script.When I leave out this redirection in the smaller example it works.

Start at problem_page, which redirects to setup_page and back again to problem page. The difficulty occurs then in problem_page when I ask it to redirect to redirect.php if the question number is >= the question array size. It's like the session array gets wiped out.

I've attached everything aswell as copying it here - not sure which way you prefer.

One that doesn't work:

<?php
//Problem_page.php - starting point
//This page should perform tasks related to asking quiz questions
//Problem lies within if statement to redirect when at the end of question list
//$num contains the question number and $count the number of questions

session_start();

//This is how I populated my questions in the session array if we arrive at this page by mistake.
//Not essential for this example - but put it in in case it has something to do with the problem.
if (!isset($_SESSION['questions'])){header('Location: setup_page.php');}

//Give values to $num and count the questions in session array
$num=1;
$count=count($_SESSION['questions']);

//This next echo seems to affect how the 'if' statement works. When commented out the page redirects and the count is 0.
//When it's included, everything works as expected. If there's something else other than the header statement in the
//'if' block, everything still works as normal. (Note I would prefer not to have to do this as I'm using CSS and
//all my page content should get prepared and displayed later.)

//echo "<h1>Not redirected</h1><p>num=$num<br>count=$count<p>";

if ($num >= $count) {header ("Location: redirect.php?num=$num&count=$count");}
//The following is an alternative to the header statement - it works as expected
//if ($num >= $count) {echo "<br> num is greater than count<br>";}
//else echo "<br>Num is less than count<br>";

echo "Everything ok";

//Just to close session and try again for testing each version of the script
echo "<br><a href=\"close_session.php\">Close the session</a>";
?>

<?php
//Setup_page.php
//Redirected here from problem_page if the session question array isn't populated
//Fill the array with questions and send it back again

session_start();

function get_questions() {
//My function gets questions from database - here's a simple one to populate the session array
$array=array("name"=>"mrob",
             "questions"=>array(1=>'What is wrong?', 2=> 'Why does it not work?', 3=>'Php is great,no?'));
$_SESSION=$array;
}

get_questions();

//Session populated with questions - send back to where it came from - problem_page
header ('Location: problem_page.php');

?>

<?php
session_start();
//Redirect.php
//shouldn't be here unless num >= count (ie. run out of questions)

//Check the values of num and count passed by the redirect from problem_page.php
echo "<h1>Redirected</h1><p>name=".$_SESSION['name']."<br>num=".$_GET['num']."<br>count=".$_GET['count']."</p>";

//Just to close session and try again for testing each version of the script
echo "<br><a href=\"close_session.php\">Close the session</a>";

?>

<?php
session_start();

unset($_SESSION['name']);
unset($_SESSION['questions']);
// kill session variables
$_SESSION = array(); // reset session array
session_destroy();   // destroy session.

echo "<a href=\"problem_page.php\">Try again</a>";

?>

Oops! Just realised I can't attach php files.
Anyway here's the shorter version without the first redirect, which works as it should,(setup_page is gone and redirect.php and close_session.php are as above):

<?php
//Problem_page.php - starting point
//This page should perform tasks related to asking quiz questions
//No problem with this page - works as expected regardless of echo being commented out or not

session_start();

//Populate the question array in session without any redirection
$array=array("name"=>"mrob",
             "questions"=>array(1=>'What is wrong?', 2=> 'Why does it not work?', 3=>'Php is great,no?'));
$_SESSION=$array;


//Give values to $num and count the questions in session array
$num=1;
$count=count($_SESSION['questions']);

//This next echo is the one I used to comment out - but it works in this version smaller_session_test as it should

//echo "<h1>Not redirected</h1><p>num=$num<br>count=$count<p>";

if ($num >= $count) {header ("Location: redirect.php?num=$num&count=$count");}
//The following is an alternative to the header statement - it works as expected
//if ($num >= $count) {echo "<br> num is greater than count<br>";}
//else echo "<br>Num is less than count<br>";

echo "Everything ok";

//Just to close session and try again for testing each version of the script
echo "<br><a href=\"close_session.php\">Close the session</a>";
?>