Session help please

movieflick

I am trying to start a session and I am having no luck. I am just doing an extremely simple form to try and figure out how to get this working. Can someone please tell me how to do this.

I am trying to get a session value $czip from a form input named czip. Here are the pages. Please note I have tried every example I could find and nothing worked.

Page 1:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<form  method="post" action="index.php">
<input name="czip" type="text"  />
<input name="submit" type="submit" /></form>
<body>
</body>
</html>

Page 2

<?php require_once('Connections/dent.php'); ?>
<?php
mysql_select_db($database_dent, $dent);
$query_shop = "SELECT frm_shop.sname FROM frm_shop WHERE frm_shop.sassignzip = '$czip' ";
$shop = mysql_query($query_shop, $dent) or die(mysql_error());
$row_shop = mysql_fetch_assoc($shop);
$totalRows_shop = mysql_num_rows($shop);
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>



<body>
<?php echo ($row_shop['sname']); ?><br />
Form submited 
</body>
</html>
<?php
mysql_free_result($shop);
?>

bodzan

...but globals which are set to off on the machine where you're trying this code...

Note that $czip can be accessed on the latter page by $POST array or as $POST['czip']... Regardless on the register globals status this should work...

You should try to read this on global variables and how they influence your coding...

Also, I would suggest to you to do the following data filtering before you use them in your SQL queries to prevent the SQL injection attack...

$variable = htmlentities($_POST['variable']);
$variable = addslashes($variable);
$variable = mysql_real_escape_string($variable);

To read more on these practices read this... And good luck with your coding... 🙂

movieflick

I understand what you are saying but I need to have a session variable in this case. I need to know how to create a session variable for this form so I can implement this on a more advanced form. I am just using this small example so I can understand how it is done. Can anyone tell me how to setup this session variable please.

Roger_Ramjet

If you want to use sessions then you do this

// start session
session_start();

// now you can add any var you want to the session array
$_SESSION['czip'] = $_POST['czip'];
$_SESSION['mytest'] = 'Hello, I\'m just an example of a session variable, hope you like me ;)';

// then on next page you also need to use session start
session_start();

// now you can access the session data like this
echo $_SESSION['czip'];
// or like this
echo $mytest;

Remember, you must have session_start() at the top of every script that you want to use sessions in.

movieflick

Ok I tried this

Page one

<?php 
session_start(); 

$_SESSION['czip'] = $_POST['czip']; 
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<form  method="post" action="index.php">
<input name="czip" type="text"  />
<input name="submit" type="submit" /></form>
<body>
</body>
</html>

Page 2

<?php 
session_start();
echo $_SESSION['czip']; 
?>


<?php require_once('Connections/dent.php'); ?>
<?php
mysql_select_db($database_dent, $dent);
$query_shop = "SELECT frm_shop.sname FROM frm_shop WHERE frm_shop.sassignzip = '$czip' ";
$shop = mysql_query($query_shop, $dent) or die(mysql_error());
$row_shop = mysql_fetch_assoc($shop);
$totalRows_shop = mysql_num_rows($shop);
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>



<body>
<?php echo ($row_shop['sname']); ?><br />
Form submited 
</body>
</html>
<?php
mysql_free_result($shop);
?>

and I get nothing. When I check the session in my tmp folder it just says czip|N;

Can someone please tell me EXACTLY what needs to be put into this form to get a session value for $czip and pass it from page to page. 😕

Roger_Ramjet

So what is posting czip to the first script then?

Debugging 101

Test all GET and POST vars before you try to use them

if (isset($_POST['czip'])) {
   $_SESSION['czip'] = $_POST['czip'];
}

That should be aprt of your permanent code.

When things are not working the way you expect then echo out everything at every stage. To begin with check all POST vars like this

foreach ($_POST as $key=>$val) {
   echo $key . ' = ' . $val . '<br />';
}

Once you are satisfied that the data is arriving at the target script you canb begin to track it through the script untill you find the error. You do that by echoing any var before using it in an IF etc.

Add echo statements inside every IF, SWITCH, and the like so that you can track the processing.

Do that and you'll find what is going wrong.

In this case it is because there is nothing in $_POST['czip']. If there is not some other script posting to the first one then it does not even exist.

My example code does work, just try the other one I posted where I made a session var out of a string and you'll see I'm right.

movieflick

edit *** I get it ********

Roger_Ramjet

I dunno what you mean by way to indepth - my debugging guide? If you tried using some of it then you would start to soluve some of these problems for yourself.

So, page one creates the var. Not a lot of point trying to put it into a session var bewfore it exists now is there.

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<form  method="post" action="index.php">
<input name="czip" type="text"  />
<input name="submit" type="submit" /></form>
<body>
</body>
</html>

<?php 
session_start();
if (isset($_POST['czip']) {
  $_SESSION['czip'] = $_POST['czip'];
}

require_once('Connections/dent.php');

mysql_select_db($database_dent, $dent);
$query_shop = "SELECT frm_shop.sname FROM frm_shop WHERE frm_shop.sassignzip = '$czip' ";
$shop = mysql_query($query_shop, $dent) or die(mysql_error());
$row_shop = mysql_fetch_assoc($shop);
$totalRows_shop = mysql_num_rows($shop);
?>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>Untitled Document</title>
</head>
<body>

<?php echo ($row_shop['sname']); ?>

<br />
Form submited 
</body>
</html>

There you are, just copy and paste it as is.

Now, you do not need to use mysql_free_result , EVER. It is explained in the manual - php is clever enough to cope with freeing resources as soon as they are finished with anyway. Just take my word for it. Same way you never need to use mysql_close, despite what you may come across in books and tutorials and sample code. They are way out of date, like 5 years, if they have either of those functions in them.

movieflick

ok thanks to Roger Ramjet and 2 days of frustration I now am able to set a session variable YAAAAY.. Well kind of. Here is the issue now:

I get the var value on page one I then pass it to the processing page which inserts the information into the DB I am using the following to set me session var

<?php
session_start(); 
if (isset($_POST['czip'])) 
{
  $_SESSION['czip'] = $_POST['czip'];
  $czip =  $_SESSION['czip'] ;
}
?>

This works like a charm thanks Roger

But then then after the data is inserted into the DB the page passes you to a reults page. I have the following to recal the session

<?php session_start();  ?>

I try to check to make sure the var is still valid so I put

<?php echo $czip ?>

And I get nothing but a blank page. I thought I might have to set everything again so I also tried

<?php
session_start(); 
if (isset($_POST['czip'])) 
{
  $_SESSION['czip'] = $_POST['czip'];
  $czip =  $_SESSION['czip'] ;
}
?>

With no luck. I checked my session file and the value was still set but for some reason I can not recal the var after I have inserted the information into the DB and then forwarded. I hope this makes sence. Any ideas?

Roger_Ramjet

That is actually down to your server settings. It used to be the case that the default was for register_globals to be ON, and so you could access any session var the way you are trying, ie $var. However, that was very insecure and nowadays the default is for register_globals to be OFF, so you either have to register then specifically, or more properly you should only access them by $_SESSION['var'].

Read about register globals for a detailed explanation.

Just get into the habit of referring to all session vars as $_SESSION['var'] and you'll be OK.

session_start();
echo $_SESSION['czip'];