preserving objects between pages

[desolator144]

Well I figured my code is horribly obvious so instead of explaining what it does, I'll just post it.

Here's my page 1 php:

include "class.php";

   $dog1 = new dog("Barko"); 

   $dog1->age = 8;

   print "My name is ";
   print $dog1->name;
   print " and I'm ";
   print $dog1->age;
   print " years old";

print " Watch me multiply 5 and 7: " . $dog1->multiply(5,7);
print " " . $dog1->bark(); 

$_SESSION['dogOne'] = $dog1;

and I want that dog to exist on the next page so I put

   include "class.php";
$dog1 = new dog("WhoCares");
	if (isset($_SESSION['dog1']))
{
	$dog1 = $_SESSION['dog1'];	
print "My name is still ";
   print $dog1->name;
   print " and I'm still ";
   print $dog1->age;
   print " years old";

}
else
{
print "No dog was found";
}

yeah I know, I'm a VB programmer and that's a very VB OOP way of doing it but I thought it would work. I gotta help someone with a php project that does something pretty much identical to this. And here's something that'll really piss you off. I actually have a PC programming AND a Web Programming degree but I barely know a thing about php. How? Cuz at my college they thought 9 weeks of php would cover it and the rest was html, javascript, XML, and AJAX. Yeah, I know, that's as stupid as it gets. I wasn't too happy either. So yeah, I don't know a ton about php so I'm sure it's something stupid causing this to not work. Basically the problem is every time I get to page 2 even from a link on page 1, it never follows the true branch of the if statement and always prints that no dog was found. Can't you just save an object to a session and make a new one and page 2 then replace it with the saved session one? VB lets you do that.
So what's up with that and is there a better way of preserving objects between pages that I should be using instead?

P.S. don't ask why my dog Barko can multiply, he just can

[bogu]

You should read this: Serializing objects - objects in sessions

[desolator144]

I actually did read that article earlier and it totally looked exactly like what to do but his code looked like he threw up on the keyboard and hit upload. I wasn't even sure it was php code 😕 never seen 2/3 of that stuff in my life. Like why is he including classa.inc instead of .php. And what's implode? Is that his function or a built in one? And what does opening a file have to do with any of this? Well I'll give it second read through and see if I can figure out his jibberish.

[NogDog]

desolator144 wrote:

I actually did read that article earlier and it totally looked exactly like what to do but his code looked like he threw up on the keyboard and hit upload. I wasn't even sure it was php code 😕 never seen 2/3 of that stuff in my life. Like why is he including classa.inc instead of .php.

[man]include/man and [man]require/man couldn't care less what the file extension is, so for include files you can use whatever extension makes sense and works well for you.

And what's implode? Is that his function or a built in one?

[man]implode/man (You can enter "http://www.php.net/function_name" in your browser to look up any PHP function.)

And what does opening a file have to do with any of this?

The example is storing the object in a file. It's just one possibility. You might also store it in a session variable, a database field, etc.

Well I'll give it second read through and see if I can figure out his jibberish.

It is part of the official PHP manual, so it's probably not "gibberish", though it certainly may be in a different style than you are used to.

[NogDog]

PS: If using PHP5+, you may also want to take a look at the sleep() and wakeup() "magic" methods.

PPS: A short example:

script1.php:

require_once 'Dog.class.php';
session_start();
$dog1 = new Dog();
$_SESSION['dog1'] = serialize($dog1);

script2.php:

require_once 'Dog.class.php';  // include class definition before you unserialize anything
session_start();
if(isset($_SESSION['dog1']))
{
   $dog1 = unserialize($_SESSION['dog1']);
}
else
{
   $dog1 = new Dog(); // or raise error here if that is more appropriate.
}

[desolator144]

ooh U guys are helpful 😃 is there any significant reason to store the object as a file? I heard a session will one way or another work out because it will do something else if it can't save itself as a cookie but is writing it out to a file more stable and reliable in some way?

Also in your code example, NogDog, my file isn't named Dog.class.php it's just dog.php but does the server require that if it's a class or is that a special way of telling the php code that runs to treat it as a class?

Also I think I made it do $dog1 = unserialize($_SESSION['dog1']); without declaring dog1 as a variable (and without unserialize) at some point and it said I can't um...do that. I forgot the error. Something about I can't access and object without instantiating one of it or something to that effect. Like in other words, it wanted me to make one first or something. So are you sure you can do that? I assume you can and it works just simply because the unserialize contains the object definitions (but not enough to not need to include the class)

[NogDog]

As I said, when including/requiring a file, PHP does not care what it is called, so the naming convention is strictly up to you. If the file is being stored in a location where it is directly accessible from the internet, you may want to give it a .php suffix just to ensure that it is not viewable by anyone who guesses it's name/location.

You should be able to directly assign the unserialize() result to a variable. The important thing though is to load the class definition before you do that (the require_once() in my example).

PS: When you store it in a session variable, it is, in fact, being stored in a file. It's just using PHP's own built-in method for storing data and retrieving it later.

[Weedpacket]

Incidentally, the serialize/unserialize is probably not necessary;

page1.php

<?php
require_once('dog.class.php');
session_start();
$dog = new Dog;
$dog->name = 'Jackie';
$_SESSION['dog1'] = $dog;
?>
<a href='page2.php'>Dog?</a>

page2.php

<?php
require_once('dog.class.php');
session_start();
if(isset($_SESSION['dog1']))
{
	echo $_SESSION['dog1']->name;
}
else
{
	echo 'No dog';
}

And of course dog.class.php

<?php
class Dog{public $name;}

Works quite fine.

Why the original code didn't is almost certainly due to the failure to start the session on either page. This is not done automatically (unless you configure PHP that way) because - well, not everyone needs session handling, and it's a waste of resources to have it if it's not needed.

Also

NogDog wrote:

It's just using PHP's own built-in method for storing data and retrieving it later.

Notice that this is just the default (not everyone has a dbms installed). You can use a database for session storage if you want.

desolator144 wrote:

...a Web Programming degree

So what letters does that put after your name?🙂