我如何卷曲这篇文章？

Question

I am trying to get an access Token from google api using code below,

$grant = urlencode("urn:ietf:params:oauth:grant-type:jwt-bearer") . "&assertion=" . $jwtSign;
$postfields = array('Host' => 'www.googleapis.com', 'Content-Type' => 'application/x-www-form-urlencoded', 'POST' => '/oauth2/v3/token HTTP/1.1', 'grant_type' => $grant);

$headers = array(
    "Content-Type: application/x-www-form-urlencoded"
);
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://www.googleapis.com/oauth2/v3/token');
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);

curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); // On dev server only!
$result = curl_exec($ch);

but I am getting error saying. Please help me what's wrong

{
 "error": "invalid_request",
 "error_description": "Required parameter is missing: grant_type"
}

Answer 1

The value of the grant_type parameter now has become a concatenation of urn:..:jwt-bearer and the assertion. They should be provided as separate parameters in the call to the token endpoint.

You're also mixing setting header fields and providing POST parameters.

Lastly, providing an array to the CURLOPT_POSTFIELDS setting will make the Content-Type change to multipart/form-data .

Rather use:

    $postfields = array(
      'grant_type' => 'urn:ietf:params:oauth:grant-type:jwt-bearer',
      'assertion' => $jwtSign
    ); 

    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, 'https://www.googleapis.com/oauth2/v3/token');
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_VERBOSE, 1);

    curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($postfields));
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0); // On dev server only!
    $result = curl_exec($ch);