CODEWITHSUNDEEP
phpclassnamespacesexists
Maxim Seshuk
Maxim Seshuk

Reputation: 213

How to check the existence of a namespace in php

I have a php library https://github.com/tedivm/Fetch and it uses Fetch namespace and I would like to check its existence in my script.

My script code:

// Load Fetch
spl_autoload_register(function ($class) {
    $file = __DIR__ . '/vendor/' . strtr($class, '\\', '/') . '.php';
    if (file_exists($file)) {
        require $file;

        return true;
    }
});

if (!class_exists('\\Fetch')) {
  exit('Failed to load the library: Fetch');
}
$mail = new \Fetch\Server($server, $port);

but this message is always displayed. But the library is fully working.

Thanks in advance for any help!

Upvotes: 21

Views: 33174

Answers (3)

XedinUnknown
XedinUnknown

Reputation: 702

As George Steel wrote, it is impossible to check for a namespace. This is because a namespace is not something that exists; only symbols exist within namespaces. See below example:

namespace Foo;

class Bar {
}

var_dump(class_exists('Foo')); // bool(false)
var_dump(class_exists('Foo\Bar')); // bool(true)

One way to think about it is the way you think about surnames: there's no such thing as a surname, you can't get a list of all surnames "standalone" without checking all people, and you therefore can't determine directly whether a surname exists; but it is part of a full name (FQN) of a person, and so you can retrieve a person's surname, or check if they belong to a surname.

It's just a way to group things. You can look around and compile a list of all things that are "red". But you can't get a list of all colours that exist.

Upvotes: 7

George Steel
George Steel

Reputation: 96

You can't check directly for the existence of a particular namespace, i.e. you'd have to class_exists('Fetch\\SomeClass'). See this question too: is it possible to get list of defined namespaces

Upvotes: 4

ars265
ars265

Reputation: 1987

You need to use the entire namespace in the class_exists I believe. So something like:

class_exists('Fetch\\Server')

Upvotes: 42

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