Rails Drive Rest Api |使用google api客户端gem共享文件

Question

我正在构建一个实现一些驱动功能的应用程序。现在我正在尝试使用google-api-ruby-client gem共享一个文件。我在使用下面的代码时遇到了一些问题。

#Here, I create a DriveService object and I authorize it.
#This works fine. In my app I list drive files well.
@drive = Google::Apis::DriveV3::DriveService.new
@drive.authorization = @token[:access_token]

#Here, first I create a permission object with some parameters
#Then I call create_permission to share the file to a other user
per=Google::Apis::DriveV3::Permission.new(type: "user", role: "writer",email_address: "some@gmail.com")
@drive.create_permission(file_id:"0B8XBWuVEmvN8YS01OXNUcHhOYWs",permission_object: per, fields: "id", &callback)

当我执行这段代码时，回调显示如下：

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

}

我不能解决这个错误。有人能帮我吗？