How to send an email, using google gmail api in php with cURL?

I have a problem sending mail using the Google Api in Php and cURL,

I tried this one:

// ENVOIE EMAIL$message="To: test@example.com\r\nFrom: test@example.com\r\nSubject: GMail test.\r\n My message";$email=base64_encode($message);$url_email = 'https://www.googleapis.com/upload/gmail/v1/users/me/messages/send';$curlPost = array('raw' => $email,);$ch = curl_init();      curl_setopt($ch, CURLOPT_URL, $url_email);      curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);curl_setopt($ch, CURLOPT_POST, 1);      curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);curl_setopt($ch, CURLOPT_HTTPHEADER, array('Authorization: Bearer '. $AccessToken, 'Accept: application/json','Content-Type: application/json'));    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($curlPost));$data = curl_exec($ch);// $data = json_decode(curl_exec($ch), true);;curl_close($ch);echo '<br/><h2>Send email</h2>';print_r($data);

But I get an error message like this :

{ "error": { "errors": [ { "domain": "global", "reason": "badContent", "message": "Media type 'application/json' is not supported. Valid media types: [message/rfc822]" } ], "code": 400, "message": "Media type 'application/json' is not supported. Valid media types: [message/rfc822]" } }

And when I tried with :

'Content-Type: message/rfc822';

I have a new error message :

{ "error": { "errors": [ { "domain": "global", "reason": "invalidArgument", "message": "Recipient address required" } ], "code": 400, "message": "Recipient address required" } }

I do not want to use the library offered by google.