Using a PHP Class to Store Configuration

In a comment on my post listing 5 Tips for Writing Cleaner PHP Code, some good arguments were made against using constants to store configuration variables. The main arguments is that it pollutes the global namespace, which can lead to collisions when implementing other code, and the way it handles typos. This article demonstrates some of the ways constants can fail, and shows an alternative.

So here is how to store these constants in a class to avoid these problems. This puts the constants in their own namespace and prevent mistakes later on.

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<?php
 
// Declaring your config class constants
class Config {
    const DB_HOST     = 'localhost',
          DB_USER     = 'username',
          DB_PASS     = 'password',
          ANOTHER_VAR = true;
}
 
echo Config::DB_HOST; // outputs localhost
 
echo Config::USER; // PHP Fatal error
 
if(Config::ANOTHER_VAR) {
    // do something
}
 
?>

That's all there is to it. Now all your constants are consolidated under one namespace and any typos will result in a fatal error. You can name the class whatever you want to be unique and avoid any collisions.

Similar Posts:

• What’s new in PHP 5.3?
• 5 Tips for Writing Cleaner PHP Code
• Snippet: Autoloading Objects (PHP 5)

Author: Steve

Steve is the owner of UlraMega Tech. He is a freelance Web designer and developer who specializes in PHP and AJAX development.