OneDrive REST API error 400 when creating folder - rest

Question

I have a problem when trying to create a folder in my OneDrive using the REST API. I'm using following documentation page https://dev.onedrive.com/items/create.htm. I have successfully authenticated and the token is working ok on other endpoints.
I spent now over a day trying every possible URI/method combination on this one but with no success. All other endpoints (directory listing etc.) are OK, just this one is driving me crazy.
If anyone could point me to the error in my approach, any help would be appreciated.
The code below returns error 400 with following message:
{"error":{"code":"invalidRequest","message":"The request is malformed or incorrect."}}
I'm using GuzzlePhp library for the request handling. My code (simplified):
$parentId = '01WZZ7ZY2LNHB75JADQJD3GGUQFSCRRZTQ'; //id to root
$method = "POST";
//none of these does the trick (to be clear, I use only one at the time)
$url = '/_api/v2.0/drive/items/'.$parentId.'/NewFolder'; //put
$url = '/_api/v2.0/drive/items/'.$parentId.'/children'; //put
$url = '/_api/v2.0/drive/items/'.$parentId.'/children'; //post
$url = '/_api/v2.0/drive/root:/NewFolder'; //post
$options = [
'headers' => [
'Authorization' => $token,
'Content-Type' => 'application/json',
'Content-Length'=> 0,
]
'form_params' => [
"name" => "NewFolder",
"folder" => (object)[],
"#name.conflictBehavior" => "fail"
]
];
//Guzzle library sends the code as specified
$res = $this->client->request($method, $url, $options);

Answer 1

The OneDrive API doesn't support form post semantics - the parameters are expected in the body as a JSON encoded blob. I haven't used Guzzle, but something like this should work:
$parentId = '01WZZ7ZY2LNHB75JADQJD3GGUQFSCRRZTQ'; //id to root
$method = "POST";
//none of these does the trick (to be clear, I use only one at the time)
$url = '/_api/v2.0/drive/items/'.$parentId.'/NewFolder'; //put
$url = '/_api/v2.0/drive/items/'.$parentId.'/children'; //put
$url = '/_api/v2.0/drive/items/'.$parentId.'/children'; //post
$url = '/_api/v2.0/drive/root:/NewFolder'; //post
$options = [
'headers' => [
'Authorization' => $token,
'Content-Type' => 'application/json',
'Content-Length'=> 0,
]
'body' =>
'{
"name": "NewFolder",
"folder": { },
"#name.conflictBehavior": "fail"
}'
];
//Guzzle library sends the code as specified
$res = $this->client->request($method, $url, $options);