根据用户是否登录显示对象

Question

I'm learning about PHP sessions for user authentication on my website. I know how to restrict the viewing of a complete page using sessions (simply check if the 'uid' session variable is set and if it is, show content, if not redirect to an error).

However I'm trying to figure out the best way to selectively show and hide different objects (div, text, images) based on if a user is logged in or not. Is it as simple as checking for the 'uid' session variable and displaying based on if it set or not? Is there a more efficient way of doing this id there are a lot of conditional elements on a page?

Answer 1

You control sessions so you can choose what to check for.

$logged = isset($_SESSION['uid']);

then the html condition:

<?php if($logged): ?>
<div>logged in content</div>
<?php endif; ?>

or without storing a temporary variable:

<?php if(isset($_SESSION['uid'])): ?>
<div>logged in content</div>
<?php endif; ?>

Answer 2

Just use if statements within the script

<?
    if(isset($_SESSION['uid'])){
?>
<div>
...
</div>
<?
    }
?>

As far as keeping things clean you really what to try to separate your html and php as much as possible. If there is a lot of data that depends on being logged in in order to be displayed you may prefer to separate that out and use include instead. This will help to keep things a little cleaner.

Answer 3

Kai has the idea, kudos for his answer using the cleaner if variant in the view.

As a minor improvement to his idea, I would either define a named constant: or create a user object to have access to the user's logged_in state application wide.

Here is a quick retake of Kai's idea with a named constant:

if(isset($_SESSION['uid'])){
  define("LOGGED_IN", 1);
}else{
  define("LOGGED_IN", 0);   
}

Then in your view / output:

<?php if(LOGGED_IN): ?>
  <div>logged in content</div>
<?php endif; ?>

The only difference is that LOGGED_IN is accessible in functions, classes, everywhere.

Last but not least, if you are familiar with OO style, creating a $user object like vascowhite seems to imply, is the way I would (and do) implement login status in my projects. In his example, $this is the $user object I am refering to.

Happy coding, good-luck friend.

Answer 4

I use an MVC framework (Zend Framework) and I provide each controler with a User object. Once the user is logged in I set a flag to true, so showing restricted content to only logged in users is as simple as:->

//content for everybody
<?php if($this->user->isLoggedIn()):?>
//top secret stuff for logged in users only
<p>Only logged in users see this</p>
<?php endif; ?>

Edit: Just to make clear; $this is the view object in the MVC framework.