PHP: check if 'use' a valid class

Question

If I fail to include a file in PHP, it reports.

But how do I know I successfully import GuzzleHttp\Cookie\CookieJar Class ?

And how do I know it is a valid Class ?

namespace GuzzleHttp;

use GuzzleHttp\Cookie\CookieJar;
use GuzzleHttp\Promise;

The `use` statement does not load the class file. You have to do this with either `include` or `require`, or by using an autoload function. — raina77ow, May 23 '17 at 19:37

score 1 · Answer 1 · answered May 23 '17 at 19:41

It is important to note that the use statement will NOT include that class, therefore it would be impossible to detect if this (statement) was succesful.

However if you would try to instantiate one of the imported classes and the import would have failed, you'd get an error.

You usually use an autoloader for this, such as composer, but you can also write one yourself. More information about this at this page: What is Autoloading; How do you use spl_autoload, __autoload and spl_autoload_register?

score 0 · Accepted Answer · answered May 23 '17 at 19:40

Nowadays most application use autoload feature from composer.

You can check if a class exist via code:

if (!class_exists(CookieJar::class)) {
    throw new Exception('class not found');
}

but class_exists probably more useful when you do dynamic stuff.

PHP: check if 'use' a valid class

2 Answers2