Persistant variables

basscheffers

Hi,

Is there a way to have persistant variables in a PHP interpreter? These do not have to be shared between threads, just in the one they are loaded.

What I am trying to do is load configuration files into memory and 'remember' other things, without doing that over and over again for each page.

I take it it is not possible to keep functions in memory between pages, sourcing everything again for every page is the only option, isn't it?

I can find very little information about PHP regarding all these things/architecture, can someone point me to it if there is some?

Thanks,
Bas.

herve

Hi,

what you want is called "session" in PHP

here you will found info :

http://www.php.net/manual/en/ref.session.php

regards,
Hervé.

basscheffers

That's not what I meant, session are user specific, I am looking for something global.

Cheers,
Bas.

herve

Well,

the way the web is functionning is "state-less".

It means taht you're executing a PHP script each
time you request an HTML page (or a script itself
of course), and when the display is finished
the script end its execution in the server.

So if you want to store something, you need
a place for that, which means : a simple text
file on the server HD or a table in a RDBMS like MySQL.

Otherwise, you could set up a special server
running like a daemon, coded maybe in C language
or PERL. His purpose is only storing and giving back
data for PHP script. That specific server running
all the time in background.

But for me it seems a bit "heavy" for such an
aim.

Hervé.

basscheffers

Thanks for your answer, but I have to dissagree with you that "stateless" means that you have to reload everything into the interpretter all the time! Java, AOLserver and Vignette don't have this limitation, for example.

So I guess the answer is no: you can't keep any values in memory.

Thanks,
Bas.

herve

Read me better.

I was talking about "the web", read "HTTP Protocol" . The HTTP Protocol IS state-less.
Which impact the way you can program things
on the web.

Of course, you can do what you want if you
are the coder of a program executed
on the server (physical).

For instance, an Apache server doesn't need
to reload its configuration file each time
it serve an HTML page 🙂

The same goes for an interpreter of a language.

But normally, the interpreter is launch
more or less every time an PHP script is request,
it's not permanently in memory of the server.

But you can code your interpreter in such a way
it stays in memory permanently, like a daemon
or service, running in background.

If that's the case, then you can (could ?) do
what you ask, remembering things between two
"sessions", two running of scripts of whatever langage.

Hope it's more clear that way.

Regards,
Hervé.

tomhath

It depends on the web server you are using. IIS allows you to have Application variables (similar to sessions, but shared across the web site).

There is also the option of using mysql heap tables. The heap tables are always kept in mimory, never written to disk. You'll need some code to initialize things when the DB server is restarted (not the web server); shouldn't be hard to detect the mysql error and call a common function to rebuild the heap tables.

I'd prefer heap tables since you have the full power of SQL to work with, and it's web server independent.