def http_post(path, data=nil, parameters={}, headers={})
      with_encoded_path_and_checked_response(path, parameters, {:data => data}) do |encoded_path|
        https_request.post(encoded_path, data, {"Content-Type" => data ? "application/json" : "text/plain", "Authorization" => "OAuth #{self.oauth_token}"}.merge(headers))
      end
    end
def http_post(path, data=nil, parameters={}, headers={})
      with_encoded_path_and_checked_response(path, parameters, {:data => data}) do |encoded_path|
        https_request.post(encoded_path, data, {"Content-Type" => data ? "application/json" : "text/plain", "Authorization" => "OAuth #{self.oauth_token}"}.merge(headers))
      end
    end
Performs an HTTP POST request to the specified path (relative to self.instance_url).  The body of the request is taken from _data_.
 Query parameters are included from _parameters_.  The required +Authorization+ header is automatically included, as are any additional
 headers specified in _headers_.  Returns the HTTPResult if it is of type HTTPSuccess- raises SalesForceError otherwise.