| # Copyright 2016 Google Inc. |
| # |
| # Licensed under the Apache License, Version 2.0 (the "License"); |
| # you may not use this file except in compliance with the License. |
| # You may obtain a copy of the License at |
| # |
| # http://www.apache.org/licenses/LICENSE-2.0 |
| # |
| # Unless required by applicable law or agreed to in writing, software |
| # distributed under the License is distributed on an "AS IS" BASIS, |
| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| # See the License for the specific language governing permissions and |
| # limitations under the License. |
| """ |
| Helper module for common telnet capability to communicate with |
| AttenuatorDevice(s). |
| |
| User code shouldn't need to directly access this class. |
| """ |
| |
| import telnetlib |
| from mobly.controllers import attenuator |
| |
| |
| def _ascii_string(uc_string): |
| return str(uc_string).encode('ASCII') |
| |
| |
| class TelnetScpiClient(object): |
| """This is an internal helper class for Telnet+SCPI command-based |
| instruments. It should only be used by those implemention control libraries |
| and not by any user code directly. |
| """ |
| |
| def __init__(self, tx_cmd_separator="\n", rx_cmd_separator="\n", prompt=""): |
| self._tn = None |
| self.tx_cmd_separator = tx_cmd_separator |
| self.rx_cmd_separator = rx_cmd_separator |
| self.prompt = prompt |
| self.host = None |
| self.port = None |
| |
| def open(self, host, port=23): |
| if self._tn: |
| self._tn.close() |
| self.host = host |
| self.port = port |
| self._tn = telnetlib.Telnet() |
| self._tn.open(host, port, 10) |
| |
| @property |
| def is_open(self): |
| return bool(self._tn) |
| |
| def close(self): |
| if self._tn: |
| self._tn.close() |
| self._tn = None |
| |
| def cmd(self, cmd_str, wait_ret=True): |
| if not isinstance(cmd_str, str): |
| raise TypeError("Invalid command string", cmd_str) |
| if not self.is_open: |
| raise attenuator.Error("Telnet connection not open for commands") |
| |
| cmd_str.strip(self.tx_cmd_separator) |
| self._tn.read_until(_ascii_string(self.prompt), 2) |
| self._tn.write(_ascii_string(cmd_str + self.tx_cmd_separator)) |
| if wait_ret is False: |
| return None |
| |
| match_idx, match_val, ret_text = self._tn.expect( |
| [_ascii_string("\S+" + self.rx_cmd_separator)], 1) |
| |
| if match_idx == -1: |
| raise attenuator.Error("Telnet command failed to return valid data") |
| |
| ret_text = ret_text.decode() |
| ret_text = ret_text.strip(self.tx_cmd_separator + self.rx_cmd_separator + |
| self.prompt) |
| |
| return ret_text |