PHP: Storing callback functions with arguments on array - php

Question

I am writing a simple router class which would allow you to execute a function when a route match is found. So, when you are defining routes, you would do something like this:
$message = 'Good morning!';
$router->addRoute('GET', 'welcome', function($message) {
echo $message;
});
Then, in the router class, this gets added to an array like:
public function addRoute($method, $pattern, $handler) {
$this->routes[$pattern] = ['method' => $method, 'handler' => $handler];
}
Once a match is found by comparing the pattern with the requested URL, I have:
return call_user_func($setting['handler']);
This gives me an error: Fatal error: Uncaught ArgumentCountError: Too few arguments to function
...so I tried using:
return call_user_func_array($setting['handler'], array($message));
...but this gives me: Notice: Undefined variable: message
How can I pass a function (including arguments, if existing) to execute within the router class using values stored on an array?

Answer 1

If you don't want to pass $message as an argument at call time, it should not be in the function parameter list. You're probably just looking to use the variable from the surrounding scope:
$message = 'Good morning!';
$router->addRoute('GET', 'welcome', function () use ($message) {
echo $message;
});