In Fusio it is possible to configure a global middleware. The middleware is executed for every route. This can be configured at the configuration.php file i.e.:

'psx_filter_pre'    => [function($request, $response, $filterChain){
    // add a custom header
    $response->setHeader('X-Foo', 'bar');

    $filterChain->handle($request, $response);
'psx_filter_post'   => [

The filter can be either a classname, closure or PSX\Http\FilterInterface instance. In the example we add a middleware which adds a custom header to every response. Please take a look at the following repository to see common middleware implementations.