Response

HTTP response has status code and message, a set of headers and a body:

HTTP/1.1 200 OK
Date: Mon, 27 Jul 2009 12:28:53 GMT
Server: Apache/2.2.14 (Win32)
Last-Modified: Wed, 22 Jul 2009 19:15:56 GMT
Content-Length: 6 
Content-Type: text/html
Connection: Closed

Hello!

Yii uses PSR-7 Response in the web application to represent response.

The object should be constructed and returned as a result of the execution of controller actions or other middleware. Usually, the middleware has a response factory injected into its constructor.

use Psr\Http\Message\ResponseFactoryInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\ServerRequestInterface;

final readonly class PostAction
{
    public function __construct(
        private ResponseFactoryInterface $responseFactory
    )
    {
    }

    public function view(ServerRequestInterface $request): ResponseInterface
    {
        $response = $this->responseFactory->createResponse();
        $response->getBody()->write('Hello!');
        return $response;
    }
}

Status code

You can set a status code like the following:

use Yiisoft\Http\Status;

$response = $response->withStatus(Status::NOT_FOUND);

Majority of status codes are available from Status class for convenience and readability.

Router may return a response before an action runs. For example, an OPTIONS request to a known route path gets an automatic 204 No Content response with an Allow header that lists supported methods. See Automatic OPTIONS responses for routing details.

Headers

You can set headers like this:

$response = $response->withHeader('Content-type', 'application/json');

If there is a need to append a header value to the existing header:

$response = $response->withAddedHeader('Set-Cookie', 'qwerty=219ffwef9w0f; Domain=somecompany.co.uk; Path=/; Expires=Wed, 30 Aug 2019 00:00:00 GMT');

And, if needed, headers could be removed:

$response = $response->withoutHeader('Set-Cookie');

Body

Response body is an object implementing Psr\Http\Message\StreamInterface.

You can write to it via the interface itself:

$body = $response->getBody();
$body->write('Hello');

Examples

Redirecting

use Yiisoft\Http\Status;

return $response
  ->withStatus(Status::PERMANENT_REDIRECT)
  ->withHeader('Location', 'https://www.example.com');

Note that there are different statuses used for redirection:

Code	Usage	What is it for
301	Status::MOVED_PERMANENTLY	Permanently changed a URL structure. Search engines update their indexes, and browsers cache it.
308	Status::PERMANENT_REDIRECT	Like 301, but guarantees the HTTP method won't change.
302	Status::FOUND	Temporary changes like maintenance pages. Original URL should still be used for future requests. Search engines typically don't update their indexes.
307	Status::TEMPORARY_REDIRECT	Like 302, but guarantees the HTTP method won't change.
303	Status::SEE_OTHER	After form submissions to prevent duplicate submissions if the user refreshes. Explicitly tells to use GET for the redirect, even if the original request was POST.

Responding with JSON

use Yiisoft\Http\Status;
use Yiisoft\Json\Json;

$data = [
    'account' => 'samdark',
    'value' => 42
];

$response->getBody()->write(Json::encode($data));
return $response
    ->withStatus(Status::OK)
    ->withHeader('Content-Type', 'application/json');