Persistent Variables

joker

Hello,

I've been searching trough the forums and such, and I have not found an answer to this.

Can PHP do something that is similar to ASPs Application object or the Java Servlet default (i believe that ColdFusion also has got one)?

These store common information in memory instead of acting upon a session or a request.

For example I could want to want to retreive all the URLs for my web application to generate a sitemap. I don't want to do this per every request, not even per every session, but once the web application starts up (and trigger an update when someone adds a page).

There are several other situations where this can be useful (the days of the month, the people in the group and so on and so on).

I suppose the right way would be to do shared memory semaphores... (Talking Unix/Apache here).

Anyone done anything like this? Anyone have an idea on how to do it?

Any comments appreciated!

Cheers!

/Jocke

Anon

you could look into cached dynamic modules. there's a series of articles on them at phpbuilder. it will only regenerate the page at set intervals, and ohterwise use a cached version.

-paul
http://xhawk.net

joker

paul,

Thanks, but that won't help me at all. I'm talking about the whole website as an application. Not caching output.

I want to be able to, on application startup, load persistent data into memory.

I might later want to cache it, however the templates you mention are not sufficient for what I'm doing.

Like I said, nothing like cacheing. I want to load data (variables, objects, constant) that are defined very seldom (not cached), for example the sitemap.
When the first hit to the web application comes, it treewalks the database to find out what the website is, and then saves it to a persistent application. Next time anyone does a request, the information is already there in the application, and in this case, the treewalk is not necessary.

Thanks anyway!

/Jocke

nevalabs

Hello,

Probably you already solved your problem, but you can take a look at the Shared Memory Functions on the PHP manual. Making use of Unix Shared Memory (and maybe semaphores), it provides what you want.

PHP Manual Entry:
LXXIX. Shared Memory Functions

Good Luck!
Regards,
Claudio Neves

joker

Claudio,

Thanks for your reply, I've looked brefily into the shared memory things, and they did not meet my criteria, the biggest reason being that they are Unix only. I do want this to be a very transparent application feature, hopefully as part of PHP (I know I should have written the specs..).

However, I'd be glad if you could provide me with some kind of example, and some kind of idea on how you protect your (shared) data.
I know there's an issue where you have a lot of users websites on a server and you do not want other people to access the application.

My idea of this thing would be a modification of the session handling functions where you would do something like

application_register($myvar, $application);

Or something like that...

Comments/suggestions/flames/praises..??!?

Thanks for your time!

/Jocke

Anon

Hi,

I just wondered whether you had solved your problem. I am looking for a way to do exactly the same thing.

I thought of writing the data from the database to a file (on the first request) and read it back for each subsequent request.

The data would be stored as a wddx packet in the file.

I am not sure of the performance issues, though...

Have you found a better way?

Regards

Martin

Anon

why not just cache the html output after the first run and read it back from the file after that point. take a look at ez_cache:
http://xhawk.net/projects/other/

joker

Martin,

No, I have not. I have it somewhere low low on my specs list to write a spec and submit it as a request for PHP.
I'm not looking for a caching solution, just so that we got that clear.
I'm looking for a persistant storage between different users sessions. (For example the web tree hierarchy; the tree walk is consuming).

I was thinking of extending (and copying) the way sessions are created and maintained.
See previous posts.

Let me know if you get to a solution like that!

/Jocke

mlaine

Jocke,

Hi again,

I have posted a code snippet (Snippet ID: 596). This is my solution to the problem... I am totally new to PHP so I am not so sure about the file locking issue. Does it fit in with what you were trying to achieve?

Regards,

Martin