问使用ruby中的google-api-client gem将文件附加到电子邮件

EN

def send_message(from:, to:, subject:, body:)
  message = RMail::Message.new
  message.header['From'] = from
  message.header['To'] = to
  message.header['Subject'] = subject
  message.body = body
  @service.send_user_message(
    'me',
    upload_source: StringIO.new(message.to_s),
    content_type: 'message/rfc822'
  )
end

upload = Google::Apis::Core::UploadIO.new('/path/to/image.png', 'image/png', 'image.png')
file_part = Google::Apis::Core::FilePart.new(nil, upload)
message_object = Google::Apis::GmailV1::Message.new(payload: file_part, raw: 'this is a test body')
service.send_user_message('me', message_object, content_type: 'message/rfc822')