Am trying to set google drive permission on a file via Curl in PHP.
google drive API

Here is API Sample Data

POST https://www.googleapis.com/drive/v3/files/FILE_ID/permissions

{
  "requests": [
    {
        "type": "user",
        "role": "commenter",
        "emailAddress": "[email protected]"
    }
  ]
}

Below is my sample code.

$access_token = 'xxxxxxxxxxxxxx';
$file_id = 'xxxxxxxxxxxxxx';

$headers = array(
"Authorization: Bearer $access_token"
);

$post_fields = '{
  "requests": [
    {
        "type": "anyone",
        "role": "reader"

    }
  ]
}';


$ch = curl_init();                                                       
curl_setopt($ch, CURLOPT_URL, "https://www.googleapis.com/drive/v3/files/$file_id/permissions");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_fields);

curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
echo $response = curl_exec($ch);

var_dump($response);

Here is the error it throws

{ "error": { "code": 400, "message": "The permission type field is required.", "errors": [ { "message": "The permission type field is required.", "domain": "global", "reason": "required", "location": "permission.type", "locationType": "other" } ] } } string(323) "{ "error": { "code": 400, "message": "The permission type field is required.", "errors": [ { "message": "The permission type field is required.", "domain": "global", "reason": "required", "location": "permission.type", "locationType": "other" } ] } } " 

it seems this permmission request data below is not properly passed in the API. Can someone help me out.

{
      "requests": [
        {
            "type": "anyone",
            "role": "reader"
    
        }
      ]
    }