# Middleware

Wolff\Core\Middleware

The middleware system of Wolff is simple and quite useful. Its routing system works just like the route system.

Adding Middlewares

There are two types of middlewares, those called before and after the request.

With that in mind, the middleware class has a before and after method to add respectively a middleware of type before and after.

before(string $url, \Closure $function)
after(string $url, \Closure $function)

The function parameter must take two parameters, the Wolff request object (instance of Wolff\Core\Http\Request), and a function that when executed, will call the next middleware. So if this function isn't executed by that middleware, the middleware chain will stop right there.

The function parameter can return a string which will be appended to the response.

Keep in mind that the middlewares are executed in the order they are added.

Examples

Middleware::before('admin/*', function($req, $next) {
    echo 'Entering in an admin page';
    $next();
});

That will render the text 'Entering in an admin page' for every page inside admin, like admin/settings, admin/panel or admin/product/info.

Middleware::before('*', function($req, $next) {
    return 'Hello world';
});

That will show the 'Hello world' text for every page inside the app.

Here's a more expresive example:

Middleware::after('home', function($req, $next) {
    echo 'Hello ';
    $next();
});

Middleware::after('home', function($req, $next) {
    echo 'World';
});

Middleware::after('home', function($req, $next) {
    echo 'This will NOT show up since the previous middleware didn\'t call next';
});

The above example will display the text 'hello world' when accessing to the home page.