header("Content-type: application/json"); echo json_encode(array('name' => 'John', 'age' => 30));
$response = new Response(); $response->setContent("Hello World!"); $response->setStatusCode(200); $response->headers->set('Content-Type', 'text/plain'); $response->send();In this example, we are creating a new Response object and setting its content to "Hello World!". We also set the HTTP status code to 200 and the content-type header to "text/plain". Finally, we send the response using the `send()` method. The package library for the PHP Response addHeader method is the Symfony HttpFoundation component. This component provides a convenient way to work with HTTP requests and responses in PHP, including the ability to set and modify headers.