PHP Session Not Saving Upon Refresh - php

Question

So, I have a PHP class that has a method which updates a session variable called $_SESSION['location']. But the problem is, each time the method is called, it doesn't find the saved session variable, and tells me it isn't set. It's supposed to store a location ID, and the method pulls the next location from a MySQL database based on the session variable, then storing the new ID. But the place in the SQL code, that's supposed to include the variable, is empty.
I do have session_start() at the beginning of the page. I've tried manually setting the variable, and it doesn't do anything either. Also tried to reach that variable from another PHP page, and no luck either. Please help.
Small sample of my code:
class location {
#session_start();
function compass($dir) {
$select = $_SESSION['location'];
if($dir == "north") {
$currentlat = mysql_result(mysql_query("SELECT `lat` FROM `locationdb` WHERE id=".$select), 0, "lat");
$currentlon = mysql_result(mysql_query("SELECT `lon` FROM `locationdb` WHERE id=".$select), 0, "lon");
$sql = "[THE SQL CODE THAT GETS THE NEXT LOCATION]";
$id = mysql_result(mysql_query($sql), 0, "id");
$_SESSION['location'] = $id;
$return['loc'] = $this->display_location($id);
$return['lat'] = $this->display_lat($id);
$return['long'] = $this->display_long($id);
$return['id'] = $id;
}
return $return;
}
}

Answer 1

I have tested your code
**Dont use session_start() in this file.
For simple testing first add this inside your compass() function.
$_SESSION['location'] .= 'World';
Then create a php script with these codes.
<?php
session_start();
$_SESSION['location'] = 'Hello';
include_once('*your name of class file*');
$obj = new location();
$obj -> compass('north');
echo $_SESSION['location'];
?>
Run this script
If the output is "HelloWorld" then your $_SESSION['location'] is working.

Answer 2

Check your phpinfo(), to see if the session save path is defined. If not, define a directory to store the sessions. In your code:
session_save_path('/DIRECTORY IN YOUR SERVER');
Then try again.

Answer 3

This is closer to what your method should look like. There are some settings that will help reduce errors being thrown when running the function. With this function, and other suggestions, you should be able to remove the error your are getting.
class location
{
public function compass($dir = '')
{
// Set the $select by $_SESSION or by your function
$select = (isset($_SESSION['location']))? $_SESSION['location']: $this->myFunctionToSetDefault();
// I set $dir to empty so not to throw error
if($dir == "north") {
$currentlat = mysql_result(mysql_query("SELECT `lat` FROM `locationdb` WHERE id=".$select), 0, "lat");
$currentlon = mysql_result(mysql_query("SELECT `lon` FROM `locationdb` WHERE id=".$select), 0, "lon");
$sql = "[THE SQL CODE THAT GETS THE NEXT LOCATION]";
$id = mysql_result(mysql_query($sql), 0, "id");
$_SESSION['location'] = $id;
$return['loc'] = $this->display_location($id);
$return['lat'] = $this->display_lat($id);
$return['long'] = $this->display_long($id);
$return['id'] = $id;
}
// This will return empty otherwise may throw error if $return is not set
return (isset($return))? $return:'';
}
}