Using The PSR-18 Client

Sending A Basic Request

use Psr\Http\Client\ClientInterface;
use Psr\Http\Message\RequestFactoryInterface;

/** @var RequestFactoryInterface $requestFactory */
$requestFactory = $container->get(RequestFactoryInterface::class);
$request = $requestFactory->createRequest('GET', 'https://example.com');

/** @var ClientInterface $client */
$client = $container->get(ClientInterface::class);
$response = $client->sendRequest($request);

$statusCode = $response->getStatusCode();
$body = (string) $response->getBody();

Sending JSON Or Other Bodies

For requests with a body, combine a request factory with a stream factory:

use Psr\Http\Client\ClientInterface;
use Psr\Http\Message\RequestFactoryInterface;
use Psr\Http\Message\StreamFactoryInterface;

/** @var RequestFactoryInterface $requestFactory */
$requestFactory = $container->get(RequestFactoryInterface::class);

/** @var StreamFactoryInterface $streamFactory */
$streamFactory = $container->get(StreamFactoryInterface::class);

$payload = json_encode([
    'email' => 'jane@example.com',
    'name' => 'Jane',
], JSON_THROW_ON_ERROR);

$request = $requestFactory
    ->createRequest('POST', 'https://api.example.com/users')
    ->withHeader('Content-Type', 'application/json')
    ->withBody($streamFactory->createStream($payload));

/** @var ClientInterface $client */
$client = $container->get(ClientInterface::class);
$response = $client->sendRequest($request);

Error Handling

PSR-18 distinguishes between transport problems and normal HTTP responses:

• network failures and invalid requests raise Psr\Http\Client\ClientExceptionInterface implementations;
• HTTP responses such as 404 and 500 do not raise exceptions on their own;
• your code should inspect the status code when a non-success response matters.

use Psr\Http\Client\ClientExceptionInterface;

try {
    $response = $client->sendRequest($request);
} catch (ClientExceptionInterface $exception) {
    // The request could not be sent or the response could not be created.
}

if ($response->getStatusCode() >= 400) {
    // Handle the application-level error response here.
}

Gotcha For New Users

Symfony\Component\HttpClient\Psr18Client also implements some PSR-17 and URI factory interfaces internally, but this package only registers it under Psr\Http\Client\ClientInterface . Keep using dedicated factory services from your HTTP factory package instead of relying on those extra interfaces being exposed automatically.