Code help

[ShaolinF]

Hey Guys,

 

What does the following code mean ?

(!isset($_SESSION['LOGGEDIN'])== FALSE)
{
}

[corbin]

!isset() would mean if the value passed to isset isn't set, and then the == false would mean if that condition before it is false...

 

So that's like saying:

 

if($_SESSION['LOGGEDIN'] IS NOT NOT SET)

 

That is basically the same as:

 

if(isset($_SESSION['LOGGEDIN'])) {

 

}

[marcus]

Isn't that sort of a contradiction?

 

If the session doesn't exist and equals the constant false... hmm.

 

[ShaolinF]

Thanks guys, I was working on some code and it was working fine and now randomly it doesnt want to work no more and Im having to go through all the code, argh!

[ShaolinF]

Well here is a piece of code which could be the cause of the problem. Please run through it and see if you can find any logical errors on the statements.

 

<?php		
if (!isset($_SESSION['LOGGEDIN'])== FALSE) // If user is not logged in
		{				
			//Add session
			//echo "session is not set! User is not logged in" . "<BR>";
			$_SESSION['LOGGEDIN'] = TRUE;
			$_SESSION['NAME'] = $_POST['name'];
			$_SESSION['CONTACTNO'] = $_POST['contact'];
			$_SESSION['EMAILADD'] = $_POST['email'];
			$_SESSION['GENDER'] = $_POST['sex'];
			$_SESSION['TIME'] = date("D dS M,Y h:i a");
		}
		else
			{
			echo "<BR>" . "session is set! User is logged in";
			//grab data from cookies if needed
			}
?>

[corbin]

Actually I think I may have had an error with the way I interpretted that....

 

isset will return either true or false, and so saying !isset() == FALSE could mean if isset != false or it could mean if (isset() == false) == false

 

Lemme check since I'm not sure.... What a weird syntax.... lol

 

Not sure how PHP would interpret that.

[corbin]

$lol = 'hi'; if(!isset($lol) == false) echo 'hi';

 

With a quick test, that echo'd 'hi', so it appears my original interpretation was correct ;p....  That's the same as going if(isset($var))

 

The problem appears to lie with:

 

if (!isset($_SESSION['LOGGEDIN'])== FALSE) // If user is not logged in

 

That means if the session var isset, but the commenting seems to imply that it thinks that will be true if the session var is not set....

 

Try

 

if(!isset($_SESSION['LOGGEDIN'])) {

[atlanta]

Yes corbin your right

 

the statement should be

 

if (!isset($_SESSION['LOGGEDIN']))

 

 

which means the user is not logged in because anytime you add ! in front it means the opposite of the answer that is going to be given back.

 

so adding the  == false would  be a contradiction

[corbin]

I know.... I was just wondering in which order PHP would eval it...

[ShaolinF]

Your a life saver. I still quite new to php and tend to get confused. So in layman terms, would isset() mean whether any content in the $var exists ?

 

!isset($var) // If there is nothing in var then ..

 

isset(var) // if there is something in var do this ..

 

correct ?

[corbin]

!function() is teh same thing as saying:

 

function() == false

 

isset will return false if the variable passed to it is/has either:

-not been initialized

-is equal to the php constant null

-been run through unset()

 

For example:

 

$v = null;

if(!isset($v)) echo 'not set';
if(!isset($nonexistant)) echo 'not set';
$v1 = 'hi';
unset($v1);
if(!isset($v1)) echo 'not set';

//this would put out not setnot setnot set

[ShaolinF]

Thanks.

 

<?php	
$refer=$_SERVER['HTTP_REFERER'];
	if($refer == ("http://www.mysite.co.uk/test/") || $refer == ("http://www.mysite.co.uk/test/index.htm") || $refer == ("http://www.mysite.co.uk/test/index.htm/")) {
		//echo "overwrite session";
		$_SESSION['LOGGEDIN'] = FALSE;
		} else {
		//do nothing
		} ?>

 

Can you see any problems with this ?

[corbin]

$_SESSION['LOGGEDIN'] = FALSE;

 

I'm not quite sure why you're script would log a user out of they came from your site x.x

 

The mysite.co.uk part has been replaced with your site right?

 

It's bad practice to rely on referrer checks since they can be spoofed easily....

[ShaolinF]

Well what happens is once someone submits a form they get directed to that page where they confirm their details. The point of the $refer statement is if the user re-submits a form, his new data will over right the old data.

 

EDIT: mysite.co.uk is replaced with my website link. The false is checked by the IF statement which I started the thread with.