Classes : some clarifications please

debbie

Hello,

I al new to classes anb have read several tutorials, message post etc. to get me started ok. I do have the following questions though, to deepen my understanding :

1) I have created my own session class which works in realtion with my database and a database connection class I created. Now, I need to pass my session object across the url to conserve it from page to page :

<form name=frmCompte action="login.php?submit=yes&SSID=<?=base64_encode(serialize(&$SSID));?>" method=post>

if (empty($SSID))
$SSID = new sessionObj();
else {
$SSID = unserialize(base64_decode($SSID));
}

This works fine, apart from the fact the my URL is about 650 characters long. I would like to just pass the object reference, but it seems to pass the same character string if I pass :
SSID=<?=base64_encode(serialize(&$SSID));?>
or
SSID=<?=base64_encode(serialize($SSID));?>
Doesn't the url have a limit off 255 characters???? I am scared I will lose my full object serialization !!

2) Where are object instances stored in PHP? Is there any way of returning all of the created object instances of a class and looping through them to check a particular value?

3) Is it important to 'destroy' unused objects or will php do that istelf? For example : On each page where I query my db, I create a new db object which has methods for select, insert etc. What happens to all those object instances? Say, there are 20 people connected to the site and each time they call a page a new db object instance is created, what happens to all the old ones?

Thanks you very much, I know these are probably basic questions, but I can't seem to figure out the answers from what i have read so far !!

Many thanks,
Debbie

laserlight

I think that if you use serialize() in PHP4, the whole object, including methods, are serialized.
Would it be possible to store this in a session, then access the session id and retrieve it?
There are other ways, but I think this makes sense based on what you seem to intend to do.
Not that I know of.
PHP4 has no destructors, though memory shouldnt be a problem since it should be released once the page is served.

debbie

Thanks for your reply ...

No, I think with serialize, I read only the object values are stored, not the methods, the methods are recreated through the class definition which is included on each page once the unserialize has been called and the object instance re-instantiated.

I don't want to use sessions, as my object replaces the inbuilt-session of php. I feel I haev more control this ay and don't have to worry about my session start ... maybe I am wrong ?

You mentioned 'there are several ways of doing this', what would they be?

What are the advanteages of using the session to do what I am trying to do ? Just that the serialize and unserialze are done for you ? If so, well, on unserialize, my wakeup funciton performs some important db tasks. Would the wakup still execute if my object was part of the session ?

Again, many thanks,

Debbie

Weedpacket

Are you hooking your class into PHP's own session-handling mechanism (i.e., using [man]session_set_save_handler[/man])? If so, then your custom session handler will operate the same way that PHP's internal session handler does now (including php.ini settings). All you'd need to do is actually implement things like session_start() and so forth.

debbie

No, I am not using sessions, just my own object. I feel I have more control over what I am doing this way, as I have to interact with the db on each page call ...

Also, i do not have access to my php.ini file and the system I am trying to write needs to be usable on any host or server, so i would prefer not to use any inbuilt php objects that may vary from one isntallation to another. That is why I want to keep maximum control over my code and the way it operates ??!!