PHP If a variable equals this or this - php

Question

I have this if statement in my PHP:
if($_SESSION['usrName']!='test1'){
header('location:login.php');
}
But i want it to be something like this:
if($_SESSION['usrName']!='test1' or 'user'){
header('location:login.php');
}
But i cant figure out how to do it in PHP code. I have tried this:
if($_SESSION['usrName']!='test1','user'){
header('location:login.php');
}
And this:
if(($_SESSION['usrName']!='test1')||($_SESSION['usrName']!='user')){
header('location:login.php');
}
Can anybody help please?

Answer 1

You have to replace the || with &&. Because you only want to redirect when both conditions are true.
if(($_SESSION['usrName']!='test1') && ($_SESSION['usrName']!='user')){
header('location:login.php');
}

Answer 2

if (!in_array($_SESSION['usrName'], array('test1', 'user')) {
header('location:login.php');
}
This checks if variable $_SESSION['usrName'] is not in list of strings to simplify additional allowed user.

Answer 3

As others have said, you need to be careful with your boolean logic - (NOT X) || (NOT Y) is equivalent to NOT (X AND Y), whereas what you want is NOT (X OR Y) which is equivalent to (NOT X) AND (NOT Y).
For this particular situation, there are also a couple of other options, although none as neat as the invalid syntaxes you tried.
First, there is in_array(), which is easy to read, but not very efficient if you use it a lot with long lists (for a simple case like this, it's not worth worrying about performance, though):
$allowed_users = array('test1', 'user');
if ( ! in_array($_SESSION['usrName'], $allowed_users ) { ... }
Or, you can build a hash with the usernames as keys; this is more efficient as the list grows, because PHP can check for a key without looping through the whole list:
$allowed_users = array('test1' => true, 'user' => true);
if ( ! array_key_exists($_SESSION['usrName'], $allowed_users) ) { ... }
// Or, if you don't mind PHP raising a few notices about accessing undefined keys
if ( ! $allowed_user[ $_SESSION['usrName'] ] ) { ... }
Finally, you can use a switch statement, with the labels falling through, and a default case acting as the "else":
switch ( $_SESSION['usrName'] )
{
case 'test1':
case 'user':
// These users are allowed :)
break;
default:
header('location:login.php');
}
Which, if any, of these you choose to use will depend on how you expect the code to grow in future, but they're useful tricks to know.

Answer 4

Your last attempt is almost correct.
However...
if (var != something || var != something-else)
...will always be true, because one of those conditions will always match. Even if it's equal to one side, it won't be equal to the other.
When you're testing two negatives like that, you need to use AND (&&) instead of OR (||).
if (($_SESSION['usrName']!='test1') && ($_SESSION['usrName']!='user'))
This will match if it's not equal to one, and also not equal to the other.

Answer 5

Currently, you're checking if either one of conditions are true. The last condition will evaluate to true if either one of the conditions are correct. I assume you're trying to check if both the the conditions are true. In that case, you'll need && instead of ||.
Try:
if( ($_SESSION['usrName'] != 'test1') && ($_SESSION['usrName'] != 'user') ) {
header('location:login.php');
}

Answer 6

You need to do something like:
if($_SESSION['usrName'] != 'test1' and $_SESSION['usrName'] != 'user'){
header('location:login.php');
}
The first attempt of yours is equivalent to:
if(($_SESSION['usrName']!='test1') or 'user'){
header('location:login.php');
}
Second seems like invalid syntax
Third is almost right, you just need to replace || with and or &&, as anything will be unequal to either 'user' or 'test1'