The order of functions in session_set_save_handler?

settingsun

My website will have a registration script that collects user data, writes it to the database, then immediately presents part of that data back to the user.

That means I'll need session_set_save_handler() to open, write to database, read from database, then close when the user logs out..

The tutorials I'm reading show the functions inside session_set_save_handler being written like this:

session_set_save_handler('open', 'close', 'read', 'write', 'destroy', 'clean')

These functions inside the "()" can't be called from left to right, because that would mean the database connection is opened, then closed before the other functions are called.

Are these functions called by php as written from left to right?

Can they be listed(written) within the parenthesis in any order that is needed for any particular script?

Can I list them as open, write, read, then close in the registration script?

I'll need to do this, because until the new user's data is written to the database, there will be nothing to read from it.

Thank you for your help

bradgrafelman

The order of the parameters for [man]session_set_save_handler/man have nothing to do with the order in which the functions will actually be called. PHP simply calls the necessary function(s) whenever needed.

settingsun

Here are a few questions to make sure I have the details right:

Are you saying the first thing that happens is this function is written with all its parameters?

The parameters are called by scripts that are written separately and outside of the session_set_save_handler() function itself?

The session_set_save_handler() function is a library of sorts that simple defines exactly what each part does, but this function does not call itself?

After I write (define) this function, I could call "function_open()" all by itself in any script anywhere that needed it - kind of like a javascript event handler?

Thanks again for your help

Weedpacket

See the manual definition for

session_set_save_handler

. It lists the parameters and describes when the corresponding functions are called.

None of the functions are called when the session_set_save_handler() function is called - there is a difference between using something and just talking about it, and that is the difference here.

If you have a function_open() function declared somewhere you can call it whenever you like - whether it's part of the session handler or not. It very much is like a JavaScript event handler (or rather, a JavaScript event handler is another example of the same programming concept).

settingsun

Could someone give me an example of how to call:

function_open()

Could it be as simple as:

if(condition)
{
function_open();
}

Also, could someone post a link to the formatting tags used to display code on this forum. I need to learn them.

Thanks

Weedpacket

settingsun wrote:
Also, could someone post a link to the formatting tags used to display code on this forum. I need to learn them.

See the FAQ.

settingsun wrote:
Could someone give me an example of how to call:

The same way you'd call any function. But why do you want to call it yourself if you're wanting it to be called by the session handler? What are you actually trying to do?

settingsun

Your question to me (why do I want to call it myself...) tells me I don't understand how it works yet.

I want to put user information in a database using a registration form.

I want registered users to be able to access their information from that database, per form element or div, with ajax, using an internal secure page (not the registration page) when they log in after registration.

I'm still trying to figure out if session_set_save_handler() makes this easier or not.

I'm learning javascript, php, html at the same time. Gotta learn it first, before I can answer these questions. No way around the learning curve. I'm learning a little php, then some javascript, etc.

The entire coding "picture" is coming together. There are still some gaps.
session_set_save_handler() is one of them.

I know it is php code that communicates with the database, but I'm still not sure what it does that's so helpful that can only be done using it.

What does this function do that can't be done with session_start(), the
$_SESSION array, mysql_query(), mysql_fetch_assoc(), and placing

$_SESSION['user data'} wherever it needs to be in the page sent to the browser?

I know these functions are necessary to do the job, that's why they are placed inside session_set_save_handler().

What happens when they are placed inside this function that doesn't happen when this handler function is not used?

The answer to this question is what I need to understand before I can really understand how this function works.

Then I'll know if I should use it. Thanks for taking the time to read all of this.