How to create a session in PHP with a randomized string?

Question

How do I keep session state of a variable throughout a site?

For example:

A user lands on my website, the string generated is

$string = 'uejsh37rhda283jde86541as';

(This string is autogenerated by an xml feed on every page refresh).

Now, everything works so far ok. The problem is when the user clicks on another page on the site, the xml feed creates a new random string.

I know I have to use sessions here, but how exactly?

if(isset($_SESSION[])): 
     ?
else: 
      ?
endif;

Updated code:

if(isset($_SESSION['session'])): 
      $string = $_SESSION['session'];
else: 
      $string = $sessionId;
      $_SESSION['session'] = $string;
endif;

echo $string;

Answer 1

if (isset($_SESSION['my_string'])) {
    $string = $_SESSION['my_string'];
}
else {
    $string = generate_random_string();
    $_SESSION['my_string'] = $string;
}
// now do something with $string

Answer 2

First of all, you need to call session_start() on all pages that access or manipulate session data.

You can do it like this:

session_start();

if (!isset($_SESSION['string'])) {

  $string = makeString();
  $_SESSION['string'] = $string;

}

Answer 3

Try this:

// call session_start() here if session handler is not started yet
if (isset($_SESSION['random-string'])) {
    $string = $_SESSION['random-string'];
} else {
    $string = generateRandomString();
    $_SESSION['random-string'] = $string;
}