Understanding Sessions/Cookies

[rsbgm]

Dear All,

Ok. Here I am again for some answers. I've gotten to understand more of things from here than other places. I hope I don't get spoiled. LOLZ...

Associative Array is an array that uses names or strings as indeces of the data stored (instead of the usual 0,1,2.. numbers). Am I right? So, in $_SESSION, I can store $_SESSION['views'], $_SESSION['timeLog'], or whatever I want as many as I can (discretely) in one user session, right? And, I can call it all in the different pages of the site in one server one session, right? And it all get's destroyed upon leaving the site, right?

It goes the same for $_COOKIES except that... that's what I don't know... the exceptions. The two has so many in common now I don't know what the true difference is. I mean, I know that cookies are set on the client's PC, while session is for server's use during the session. But, is there more to it than just those two? Can I also create different cookie values during the session and destroy those without destroying the real cookie stored in the client's PC while it hasn't expired? Using both at the same time is the way to go, is it really?

These and many more are things that confuses me with both cookies and sessions. Any input will really help in drawing the line between the two. Please feel free to criticize, holler, or blast any info for me. I'd appreciate it. Don't get me wrong, I like cookies better than session. They're delicious. Session, it depends whether it's a pot session, friendly make out session, or whatever... LOLZ... Oh, and I've read those tutorials at Tizag, w3s, php.net, etc... I just need to here it from other folks how they understand both to better understand it myself.

When else and where else to use which?

My apologies. Aparently, for beginners like me, knowing both seem more confusing.

@Markus (and the other moderators)

Please share your wisdom for me and other beginners out there.

Thanks

rsbgm

[rsbgm]

ps: Do I have to set sessions and/or cookies on each page of the site?


rsbgm

[Markus]

Dear All,

Ok. Here I am again for some answers. I've gotten to understand more of things from here than other places. I hope I don't get spoiled. LOLZ...

It's ok, as long as you don't get selfish! Give a little back to the community when you can.

Associative Array is an array that uses names or strings as indeces of the data stored (instead of the usual 0,1,2.. numbers). Am I right? So, in $_SESSION, I can store $_SESSION['views'], $_SESSION['timeLog'], or whatever I want as many as I can (discretely) in one user session, right? And, I can call it all in the different pages of the site in one server one session, right? And it all get's destroyed upon leaving the site, right?

You can name associative arrays with alphanumeric characters, and a few others (underscores).

Yes, they are destroyed when the browser is closed. They can be destroyed earlier, manually (session_destroy(), unset()) or systematically (depending on how you set the sessions lifetime).

It goes the same for $_COOKIES except that... that's what I don't know... the exceptions. The two has so many in common now I don't know what the true difference is. I mean, I know that cookies are set on the client's PC, while session is for server's use during the session. But, is there more to it than just those two?

Not a whole lot of difference, tbh. You know the main difference. What makes them different is how you should be using them: Cookies should not hold sensitive data, not to mention un-encrypted data, as they are visible to the end-user.

Can I also create different cookie values during the session and destroy those without destroying the real cookie stored in the client's PC while it hasn't expired? Using both at the same time is the way to go, is it really?

I don't understand this part.

These and many more are things that confuses me with both cookies and sessions. Any input will really help in drawing the line between the two. Please feel free to criticize, holler, or blast any info for me. I'd appreciate it. Don't get me wrong, I like cookies better than session. They're delicious. Session, it depends whether it's a pot session, friendly make out session, or whatever... LOLZ... Oh, and I've read those tutorials at Tizag, w3s, php.net, etc... I just need to here it from other folks how they understand both to better understand it myself.

When else and where else to use which?

Again, the main distinction between the use of sessions vs. cookies is the kind of data it will hold. Never allow the end-user to see sensitive data! EVER! ;)

My apologies. Aparently, for beginners like me, knowing both seem more confusing.

@Markus (and the other moderators)

Please share your wisdom for me and other beginners out there.

Thanks

rsbgm

Hope this was a little helpful and cleared some doubts, maybe.

- mark.

[Markus]

@rsbgm
Only on parts of your site that require them..

session_start() must be called on any page that needs access to the $_SESSION array (unless your php settings start it automatically).

- Mark.

[rsbgm]

@Markus

About the part you didn't understand on cookies...

Let's say at the start of the visit (first time) we set the cookie:

setcookie (name, value, exp);

I understand that u can set another cookie during the session (for some reason you need to in your coding)... and another... and another...:

setcookie(name2, value2, exp2);
setcookie(name3, value3, exp3);
setcookie(name4, value4, exp4);

Now, unlike SESSION which expires after the visit, you can access any of the above cookies on the next visit as long as it hasn't expired. Also, if u want to destroy one cookie, you can by specifying the cookie name.

Is this about right? Can u use cookies this way?

rsbgm

[Markus]

@rsbgm
Yeah, that's correct. You can set multiple sessions from different regions of your code, too, though. And you can also delete individual sessions, like cookies.

- mark.

[rsbgm]

Wow! Thanks a lot, man!

KUDOS!!!

rsbgm

[Markus]

@rsbgm
Np, rsbgm.

Keep it real*,

- Mark.

*I'm feelin' cool.

[rsbgm]

You mentioned that in order for SESSION variables to be accessed, you have to start_session() on that page. How about COOKIES? Does it need anything on the top of the page in order to access it? It's practically just gonna check the clients PC for the information everytime you invoke the code, right?

Now... this may be a bit off topic, but, bear with me on this question... (before I make some conclusions)...

POST/GET/REQUEST are associative arrays as well. This is usually set through input forms. This cannot be set like an ordinary variable that you can just assign a value. I understand how it is passed on from the FORM page to the PHP page with the POST code, but, can you also call that POST variable on other pages? Does it also need some code on top of the page that will be accessing the POST variable?

rsbgm

[Markus]

@rsbgm
POST, GET and COOKIE are all of the same cloth, actually. They're called 'super globals', meaning they're available throughout any php scripts you make - you need not 'instantiate' them or use the 'global' keyword.. REQUEST checks all 3 of the above arrays for whatever key you look for. In fact, SESSION is also a superglobal but does need to be 'started' for access to it to be available - COOKIE does not.

Does that answer your question?

Edit - it doesn't check the clients browser when ever your code is run - only when you access the COOKIE array.

<?php
// Some stuff here. PHP couldn't care less about COOKI right now.
 
echo $_COOKIE['hello']; // PHP now access the array.
?>
 

[rsbgm]

Yes, it does. Again, thank you very mucho!

rsbgm

[Markus]

Keine problem,

- mark.