| #!/usr/bin/python3.4 |
| |
| # Copyright 2014- The Android Open Source Project |
| # |
| # 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 AttenuatorInstrument(s). |
| |
| User code shouldn't need to directly access this class. |
| """ |
| |
| |
| import telnetlib |
| from acts.controllers import attenuator |
| |
| |
| def _ascii_string(uc_string): |
| return str(uc_string).encode('ASCII') |
| |
| |
| class _TNHelper(): |
| #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 |
| |
| def open(self, host, port=23): |
| if self._tn: |
| self._tn.close() |
| |
| self._tn = telnetlib.Telnet() |
| self._tn.open(host, port, 10) |
| |
| 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.InvalidOperationError("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.InvalidDataError("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 |