Is there a way to execute required php file once per session? - php

Question

I am new to php and have just written a basic index.php that will display family tree information for an individual based on input id.
The index.php includes a file called "xml-people-list.php" which loads the information from the family tree and creates a sorted list of people.
My problem is that every time you click on a person to display their details, the included php is reloaded which causes the read from file and creation of sorted list to happen again.
Is there a way to only run this code once per session to avoid multiple loads?
I tried to look at session variables but wasn't sure if they would help or how to use them in this case or if there is another way?
Contents of "xml-people-list.php:
<?php require 'xml-load-person.php';
if (file_exists('people.xml'))
{
$people = simplexml_load_file('people.xml');
foreach ($people->person as $person)
{
$person_list[(string)$person['ID']] = strtoupper($person->FamilyName) . ", " . $person->GivenNames;
}
asort($person_list);
}
else
{
exit('Failed to open people.xml.');
}
?>
Thanks for any help!

Answer 1

Yes, you could use session variables. If you wanted to only parse the list once per visitor, and then "cache" the result into a session variable, you could do something like this (for a simple example):
if (!empty($_SESSION['person_list'])) {
// Here we fetch and decode the the ready list from a session variable, if it's defined:
$person_list = json_decode($_SESSION['person_list']);
}
// Otherwise we load it:
else {
require 'xml-load-person.php';
if (file_exists('people.xml'))
{
$people = simplexml_load_file('people.xml');
foreach ($people->person as $person)
{
$person_list[(string)$person['ID']] = strtoupper($person->FamilyName) . ", " . $person->GivenNames;
}
asort($person_list);
// Here we assign the ready list to a session variable (as a JSON string):
$person_list = json_encode($person_list);
$_SESSION['person_list'] = $person_list;
// Here we revert the JSON-encoded (originally SimpleXML) object into a stdClass object.
$person_list = json_decode($person_list);
}
else
{
exit('Failed to open people.xml.');
}
}
You will need to call session_start() in your file (either this one, or any other file including it, but importantly before any output is sent to the browser). Homework: Read up on sessions in PHP.
Update: Since SimpleXML objects can't be serialized, and since adding an object to $_SESSION causes serialization, I've updated the answer to json_encode/decode the object. Yes there's a bit of processing, but that'd be the case with the default serialization as well, and json_en/decode is fairly light-weight. Certainly heaps lighter than parsing XML on each page load!
Be aware that the returned object will be a stdClass object, not a SimpleXML object. I'm assuming it won't be a problem in your use case.

Answer 2

Maybe try require_once() function

Answer 3

1) First of all, try to see if your buttons are anchor tags then be sure that the href attribute is directing to # example: <a href="#">
2) try to use include_once instead of requiring
3) if you tried this and these couple solutions didn't work for you you can send the id of a person using the global $_GET variable
//this should be you URL http://localhost/projectname/index.php?person_id=1
// your href of each person should appoint to their URL
// <a href="index.php?person_id=1">
you can use this $_GET['person_id'] and store it into a variable so it will give you the id of person.