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PHP PHP Arrays and Control Structures PHP Conditionals Switch Statements

Mahfuzur Rahman
Mahfuzur Rahman
3,204 Points
Posted by Mahfuzur Rahman
Mahfuzur Rahman
3,204 Points

role of if statement

I can't understand what the if statement is doing here. I know the function of an if statement. Is isset a predefined function?
//Available roles: admin, editor, author, subscriber if (!isset($role)) { $role = 'subscriber'; }

switch.php 
<?php
//Available roles: admin, editor, author, subscriber
if (!isset($role)) {
    $role = 'subscriber';
}

//change to switch statement
if ($role != 'admin') {
    echo "You do not have access to this page. Please contact your administrator.";
}

1 Answer

adefee
adefee
4,705 Points

isset() is a predefined function that checks if a string is 'set': that is that the variable exists and is not NULL.

So, in the code you pasted, we're doing the following:

  • See if a $role exists.
  • If it does not exist (! before isset() tells it to check for false instead of true), then set the user's $role to 'subscriber'.
  • Finally, if the user's $role is not 'admin', then we echo out a notice informing them they don't have appropriate access.

Essentially that's the basics for defining a permission-based system in PHP. If you want to read more about isset(), you can see the entry in the PHP manual (bookmark it, it's the goto for everything PHP) here: http://php.net/manual/en/function.isset.php