Still celebrating National IT Professionals Day with 3 months of free Premium Membership. Use Code ITDAY17

x
?
Solved

== not working the way Id expect it

Posted on 2016-07-19
7
Medium Priority
?
77 Views
Last Modified: 2016-07-26
Im trying to test if a variable is the same as another vairable:-
if ($_SESSION['loggedIn'] == $authKey) {

Open in new window


Which its saying it is, however it shouldn't, to debug I added:-
		echo "authKey = " . $authKey . "<br/>";
		echo "SESSION loggedIn - " . $_SESSION['loggedIn'] . "<br/>";

Open in new window


Which returns:-

authKey = 5f8e4f8b-f7db-4c6c-8beb-0336a7e1b443
SESSION loggedIn - 1

And then to test further I used:-
		if ($_SESSION['loggedIn'] == $authKey) {
			echo "T";
		} else {
			echo "F";
		}

Open in new window


Which returns T.

I dont understand why its returning that it is the same, when it isnt.

Any ideas how to fix it and why its happening?
0
Comment
Question by:tonelm54
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
7 Comments
 
LVL 111

Accepted Solution

by:
Ray Paseur earned 2000 total points
ID: 41718998
These isolated fragments of code are probably masking the problem, which will be better represented by the SSCCE (a sample that demonstrates the error, one we can install and run).  There is nothing inherently wrong in your code as you've shown it here, but this is not a code problem, it is a data-dependent problem, so we would need to see the origins of the data (variables) that are in play.  Are you using session_start() on all pages?

Useful references:
http://php.net/manual/en/types.comparisons.php
http://php.net/manual/en/language.operators.comparison.php
http://php.net/manual/en/language.types.type-juggling.php

Please see: https://iconoun.com/demo/temp_tonelm54.php
<?php // demo/temp_tonelm54.php
/**
 * https://www.experts-exchange.com/questions/28958236/not-working-the-way-Id-expect-it.html
 *
 * An Example SSCCE
 * http://sscce.org/
 *
 * Note that there is no session_start() statement in this example.  Not needed for this test.
 *
 */
error_reporting(E_ALL);
echo '<pre>';


// ASSIGN OUR TEST VARIABLES
$authKey = "123";
$_SESSION['loggedIn'] = "123";

// SHOW OUR TEST VARIABLES
echo "authKey = " . $authKey . "<br/>";
echo "SESSION loggedIn - " . $_SESSION['loggedIn'] . "<br/>";

// USE OUR TEST VARIABLES
if ($_SESSION['loggedIn'] == $authKey) {
	echo "T";
} else {
	echo "F";
}

Open in new window

Outputs:
authKey = 123
SESSION loggedIn - 123
T

Open in new window

0
 
LVL 31

Expert Comment

by:Marco Gasi
ID: 41719009
Because, when you compares a number with a string, the string is converted in a number; any string which doesn't start with a number is converted to 0, the other to 1, so your comparison is

if 1 == 1 -> true

Replace equal operator == with identical operator === to avoid this issue.

But your code doesn't make sense to me because you're comparing a boolen value (loggedin which can be 0 or 1) with a string which represents a token so you'll always get false. You should change the logic and store ina  cookie or in the $_SESSION array the authKey when it is assigned and then perform your comparison against the coockie or the $_SESSION value
0
 
LVL 111

Expert Comment

by:Ray Paseur
ID: 41719015
@Marco: I don't see it that way.  Check out this example.  That's why I think we are missing an important piece of the puzzle.

Please see: https://iconoun.com/demo/temp_tonelm54_FALSE.php
<?php // demo/temp_tonelm54_FALSE.php
/**
 * https://www.experts-exchange.com/questions/28958236/not-working-the-way-Id-expect-it.html
 *
 * An Example SSCCE
 * http://sscce.org/
 *
 * Note that there is no session_start() statement in this example.  Not needed for this test.
 *
 */
error_reporting(E_ALL);
echo '<pre>';


// ASSIGN OUR TEST VARIABLES
$authKey = "5f8e4f8b-f7db-4c6c-8beb-0336a7e1b443";
$_SESSION['loggedIn'] = "1";

// SHOW OUR TEST VARIABLES
echo "authKey = " . $authKey . "<br/>";
echo "SESSION loggedIn - " . $_SESSION['loggedIn'] . "<br/>";

// USE OUR TEST VARIABLES
if ($_SESSION['loggedIn'] == $authKey) {
	echo "T";
} else {
	echo "F";
}

Open in new window

Outputs:
authKey = 5f8e4f8b-f7db-4c6c-8beb-0336a7e1b443
SESSION loggedIn - 1
F

Open in new window

That aside, the correct (working) design for PHP client authentication is shown in this article:
https://www.experts-exchange.com/articles/2391/PHP-Client-Registration-Login-Logout-and-Easy-Access-Control.html
0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 31

Expert Comment

by:Marco Gasi
ID: 41719017
Wooops, I see...
1
 
LVL 84

Expert Comment

by:Dave Baldwin
ID: 41719683
One of the thing that "session_start()" does is create or find the file that session data is stored in.  While it may not affect this simple demo, it is never a good idea to try to use $_SESSION variables without it.  You certainly can't expect to store any $_SESSION variables without it and expect them to be there on a second page.
1
 
LVL 111

Expert Comment

by:Ray Paseur
ID: 41719869
Dave: Agreed, 100%, and that's why I asked about it right at the top.

In any real-world example session_start() would be a common-sense thing to do, but it's not necessary in this instance, and I didn't include it to avoid cluttering up my session with E-E test data.  I did, however, make note of this in the script comments, since it's one of those things that requires explanation.
0
 

Author Closing Comment

by:tonelm54
ID: 41729300
Weirdly, my code still doesn't produce the right answer, but when I run yours it does, so must be something weird happening somewhere else thats throwing it off. Its only POC anyways
0

Featured Post

VIDEO: THE CONCERTO CLOUD FOR HEALTHCARE

Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

I imagine that there are some, like me, who require a way of getting currency exchange rates for implementation in web project from time to time, so I thought I would share a solution that I have developed for this purpose. It turns out that Yaho…
Nothing in an HTTP request can be trusted, including HTTP headers and form data.  A form token is a tool that can be used to guard against request forgeries (CSRF).  This article shows an improved approach to form tokens, making it more difficult to…
The viewer will learn how to dynamically set the form action using jQuery.
The viewer will learn how to create and use a small PHP class to apply a watermark to an image. This video shows the viewer the setup for the PHP watermark as well as important coding language. Continue to Part 2 to learn the core code used in creat…

660 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question