Guzzle not sending PSR-7 POST body correctly

Question

It is either not being sent, or not being received correctly. Using curl direct from the command line (using the -d option) or from PHP (using CURLOPT_POSTFIELDS) d

Answer 1

The GuzzleHttp\Client provides all necessary wrapping.

$response = $client->post(
    $uri,
    [
        'auth' => [null, 'Bearer ' . $token],
        'form_params' => $parameters,
]);

Documentation available Guzzle Request Options

Edit: However, if your requests are being used within GuzzleHttp\Pool then, you can simply everything into the following:

$request = new GuzzleHttp\Psr7\Request(
    'POST',
    $uri,
    [
       'Authorization' => 'Bearer ' . $token,
       'Content-Type' => 'application/x-www-form-urlencoded'

    ],
    http_build_query($form_params, null, '&')
);