Registering objects in sessions

[MrRosary]

I have been working on a XML rather than databse based system recently.

I didnt want to keep writing and parsing XML on each page for user preferences etc. The logical place then is to store them in a cookie.

As I am trying to be as object orientated as possible I want to store an object containing the data and the code to access them in a cookie.

The only really good reference to this I could find was on the zend site at
http://www.zend.com/manual/language.oop.serialization.php

I adapted the examples on this page to work with cookies by stripping out the file handling code and adding in.

session_register('a');

in the first page's code and taking out the file handling code in the second page and just leaving it with
session_start();
$a->show_one();

At the moment the cookie is set with the serialized data in it. However it is not accessed or possible unserialised on the second page as I get
fatal error call to a member funtion on a non object.

I am baffled here? Any Ideas?

MrRosary

[archangel_617b]

You need to [man]session_register/man the object on the receiving page (based on what I can see here). Also, if you are using session_register(), you do not need to call [man]session_start/man.

Hope this fixes your problem 😛

[MrRosary]

I dont think i made myself clear here....

the first page creates the object
with
$a = new test
then registers it in the session with
session_register('a');
the first page just has a link to the second page.

The second page just has this code in it
session_start();
$a->show_one();

Its this second page that throws up the fatal error. Both pages have the code to define the class in them to be safe.

As far as I can see the obect $a is being deserialized but not as an instance of the right class. Its then a memeber of the standard class which has no methods that can be called.

When I added a
print_r(HTTP_SESSION_VARS);
to the second page to have a closer look at what was going on I got
Array ( [a] => barfoo Object ( [one] => 1 ) )
It looks to me like the object is in the session just fine and unserialized(?) how do i get to access its method?

Mr.Rosary

[archangel_617b]

Do either of these:

1. session_register('a'); on page 2 will allow you to call $a->method();

2. $_SESSION['a']->method(); can be used if you do not wish to register the session vairable.

The problem is that $a has not been made available on page 2 though you started the session (hence why your print_r() worked). Check [man]session_register[/man] for details on its use.

[ednark]

after trying to work with xml i came to the conclusion that its just too much overhead unless you are really passing info from your php to some other non php system...

this is an example of storing a small piece of complex php outside of a database within a session and a flat file using serialize

its a little long to look at but, you should be able to copy and paste this and it should work right away if you have register globals off...

somthing like this may be what you are lookignng to do

<?php
session_start();

$obj = new StorableObject('./storable.data');
$obj->one = 'IM IN A SESSION';
$obj->two = 'IM IN A SESSION';
$obj->storeInSession();

$obj->one = 'IM IN A FILE';
$obj->two = 'IM IN A FILE';
$obj->saveToFile();

$obj->one = 'IM JUST AN OBJECT';
$obj->two = 'IM JUST AN OBJECT';


$obj_from_session = new StorableObject('./storable.data');
$obj_from_session->loadFromSession();

$obj_from_file = new StorableObject('./storable.data');
$obj_from_file->loadFromFile();


print "<br><br><u>This is our object we created</u>:<br>";
print "<pre>";
print_r( $obj );
print "</pre>";

print "<br><br><u>This is our object from our file</u>:<br>";
print "<pre>";
print_r( $obj_from_file );
print "</pre>";

print "<br><br><u>This is our object from our session</u>:<br>";
print "<pre>";
print_r( $obj_from_session );
print "</pre>";


print "<br><br><u>This is what gets stored in our session</u>:<br><br>";
print_r( $_SESSION[$obj->uid] );

print "<br><br><u>This is what gets stored in the first line of our file</u>:<br><br>";
readfile($obj->uid);


class StorableObject
{
    var $uid;

var $one;
var $two;

function StorableObject( $uid )
{
    $this->uid = $uid;
    $this->one = NULL;
    $this->two = NULL;
}

function loadFromFile()
{
    $lines = file($this->uid);
    $this->cloneFrom(unserialize($lines[0]));
}

function saveToFile()
{
    if ( file_exists($this->uid) ) {
        $fp = fopen( $this->uid, 'w' );
        fwrite($fp,serialize($this));
        fclose($fp);
    }
}

function cloneFrom( $obj )
{
    $this->one = $obj->one;
    $this->two = $obj->two;
}

function loadFromSession()
{
    if ( isset($_SESSION[$this->uid]) ) {
        $this->cloneFrom( unserialize($_SESSION[$this->uid]) );
    }
}

function storeInSession()
{
    $_SESSION[$this->uid] = serialize($this);
}
}

?>

[/code]

[MrRosary]

I will have to try these out when i get home tonight.

I wouldnt be using xml like this either. Thats what databases are for.

I have a freind who wants a "database" driven site but who isnt willing to pay for hosting with a database. I can get php only hosting for free for her and XML seems to be a better way to go than flat files to store data.

MrRosary

[MrRosary]

Everything works a lot better with Register Globals turned on 😃

I was doing this on a out of the box Red Hat 8.0 install. Its just one of the many things that isn't /quite/ right with php on red hat 8.0

I could mention the fact they forgot to include MySQL support for php in the install..... long tags on by default......

MrRosary