| #! python |
| # |
| # This module implements a simple socket based client. |
| # It does not support changing any port parameters and will silently ignore any |
| # requests to do so. |
| # |
| # The purpose of this module is that applications using pySerial can connect to |
| # TCP/IP to serial port converters that do not support RFC 2217. |
| # |
| # This file is part of pySerial. https://github.com/pyserial/pyserial |
| # (C) 2001-2015 Chris Liechti <cliechti@gmx.net> |
| # |
| # SPDX-License-Identifier: BSD-3-Clause |
| # |
| # URL format: socket://<host>:<port>[/option[/option...]] |
| # options: |
| # - "debug" print diagnostic messages |
| |
| from __future__ import absolute_import |
| |
| import errno |
| import logging |
| import select |
| import socket |
| import time |
| try: |
| import urlparse |
| except ImportError: |
| import urllib.parse as urlparse |
| |
| from serial.serialutil import SerialBase, SerialException, to_bytes, \ |
| PortNotOpenError, SerialTimeoutException, Timeout |
| |
| # map log level names to constants. used in from_url() |
| LOGGER_LEVELS = { |
| 'debug': logging.DEBUG, |
| 'info': logging.INFO, |
| 'warning': logging.WARNING, |
| 'error': logging.ERROR, |
| } |
| |
| POLL_TIMEOUT = 5 |
| |
| |
| class Serial(SerialBase): |
| """Serial port implementation for plain sockets.""" |
| |
| BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, |
| 9600, 19200, 38400, 57600, 115200) |
| |
| def open(self): |
| """\ |
| Open port with current settings. This may throw a SerialException |
| if the port cannot be opened. |
| """ |
| self.logger = None |
| if self._port is None: |
| raise SerialException("Port must be configured before it can be used.") |
| if self.is_open: |
| raise SerialException("Port is already open.") |
| try: |
| # timeout is used for write timeout support :/ and to get an initial connection timeout |
| self._socket = socket.create_connection(self.from_url(self.portstr), timeout=POLL_TIMEOUT) |
| except Exception as msg: |
| self._socket = None |
| raise SerialException("Could not open port {}: {}".format(self.portstr, msg)) |
| # after connecting, switch to non-blocking, we're using select |
| self._socket.setblocking(False) |
| |
| # not that there is anything to configure... |
| self._reconfigure_port() |
| # all things set up get, now a clean start |
| self.is_open = True |
| if not self._dsrdtr: |
| self._update_dtr_state() |
| if not self._rtscts: |
| self._update_rts_state() |
| self.reset_input_buffer() |
| self.reset_output_buffer() |
| |
| def _reconfigure_port(self): |
| """\ |
| Set communication parameters on opened port. For the socket:// |
| protocol all settings are ignored! |
| """ |
| if self._socket is None: |
| raise SerialException("Can only operate on open ports") |
| if self.logger: |
| self.logger.info('ignored port configuration change') |
| |
| def close(self): |
| """Close port""" |
| if self.is_open: |
| if self._socket: |
| try: |
| self._socket.shutdown(socket.SHUT_RDWR) |
| self._socket.close() |
| except: |
| # ignore errors. |
| pass |
| self._socket = None |
| self.is_open = False |
| # in case of quick reconnects, give the server some time |
| time.sleep(0.3) |
| |
| def from_url(self, url): |
| """extract host and port from an URL string""" |
| parts = urlparse.urlsplit(url) |
| if parts.scheme != "socket": |
| raise SerialException( |
| 'expected a string in the form ' |
| '"socket://<host>:<port>[?logging={debug|info|warning|error}]": ' |
| 'not starting with socket:// ({!r})'.format(parts.scheme)) |
| try: |
| # process options now, directly altering self |
| for option, values in urlparse.parse_qs(parts.query, True).items(): |
| if option == 'logging': |
| logging.basicConfig() # XXX is that good to call it here? |
| self.logger = logging.getLogger('pySerial.socket') |
| self.logger.setLevel(LOGGER_LEVELS[values[0]]) |
| self.logger.debug('enabled logging') |
| else: |
| raise ValueError('unknown option: {!r}'.format(option)) |
| if not 0 <= parts.port < 65536: |
| raise ValueError("port not in range 0...65535") |
| except ValueError as e: |
| raise SerialException( |
| 'expected a string in the form ' |
| '"socket://<host>:<port>[?logging={debug|info|warning|error}]": {}'.format(e)) |
| |
| return (parts.hostname, parts.port) |
| |
| # - - - - - - - - - - - - - - - - - - - - - - - - |
| |
| @property |
| def in_waiting(self): |
| """Return the number of bytes currently in the input buffer.""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| # Poll the socket to see if it is ready for reading. |
| # If ready, at least one byte will be to read. |
| lr, lw, lx = select.select([self._socket], [], [], 0) |
| return len(lr) |
| |
| # select based implementation, similar to posix, but only using socket API |
| # to be portable, additionally handle socket timeout which is used to |
| # emulate write timeouts |
| def read(self, size=1): |
| """\ |
| Read size bytes from the serial port. If a timeout is set it may |
| return less characters as requested. With no timeout it will block |
| until the requested number of bytes is read. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| read = bytearray() |
| timeout = Timeout(self._timeout) |
| while len(read) < size: |
| try: |
| ready, _, _ = select.select([self._socket], [], [], timeout.time_left()) |
| # If select was used with a timeout, and the timeout occurs, it |
| # returns with empty lists -> thus abort read operation. |
| # For timeout == 0 (non-blocking operation) also abort when |
| # there is nothing to read. |
| if not ready: |
| break # timeout |
| buf = self._socket.recv(size - len(read)) |
| # read should always return some data as select reported it was |
| # ready to read when we get to this point, unless it is EOF |
| if not buf: |
| raise SerialException('socket disconnected') |
| read.extend(buf) |
| except OSError as e: |
| # this is for Python 3.x where select.error is a subclass of |
| # OSError ignore BlockingIOErrors and EINTR. other errors are shown |
| # https://www.python.org/dev/peps/pep-0475. |
| if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| except (select.error, socket.error) as e: |
| # this is for Python 2.x |
| # ignore BlockingIOErrors and EINTR. all errors are shown |
| # see also http://www.python.org/dev/peps/pep-3151/#select |
| if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| if timeout.expired(): |
| break |
| return bytes(read) |
| |
| def write(self, data): |
| """\ |
| Output the given byte string over the serial port. Can block if the |
| connection is blocked. May raise SerialException if the connection is |
| closed. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| |
| d = to_bytes(data) |
| tx_len = length = len(d) |
| timeout = Timeout(self._write_timeout) |
| while tx_len > 0: |
| try: |
| n = self._socket.send(d) |
| if timeout.is_non_blocking: |
| # Zero timeout indicates non-blocking - simply return the |
| # number of bytes of data actually written |
| return n |
| elif not timeout.is_infinite: |
| # when timeout is set, use select to wait for being ready |
| # with the time left as timeout |
| if timeout.expired(): |
| raise SerialTimeoutException('Write timeout') |
| _, ready, _ = select.select([], [self._socket], [], timeout.time_left()) |
| if not ready: |
| raise SerialTimeoutException('Write timeout') |
| else: |
| assert timeout.time_left() is None |
| # wait for write operation |
| _, ready, _ = select.select([], [self._socket], [], None) |
| if not ready: |
| raise SerialException('write failed (select)') |
| d = d[n:] |
| tx_len -= n |
| except SerialException: |
| raise |
| except OSError as e: |
| # this is for Python 3.x where select.error is a subclass of |
| # OSError ignore BlockingIOErrors and EINTR. other errors are shown |
| # https://www.python.org/dev/peps/pep-0475. |
| if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('write failed: {}'.format(e)) |
| except select.error as e: |
| # this is for Python 2.x |
| # ignore BlockingIOErrors and EINTR. all errors are shown |
| # see also http://www.python.org/dev/peps/pep-3151/#select |
| if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('write failed: {}'.format(e)) |
| if not timeout.is_non_blocking and timeout.expired(): |
| raise SerialTimeoutException('Write timeout') |
| return length - len(d) |
| |
| def reset_input_buffer(self): |
| """Clear input buffer, discarding all that is in the buffer.""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| |
| # just use recv to remove input, while there is some |
| ready = True |
| while ready: |
| ready, _, _ = select.select([self._socket], [], [], 0) |
| try: |
| if ready: |
| ready = self._socket.recv(4096) |
| except OSError as e: |
| # this is for Python 3.x where select.error is a subclass of |
| # OSError ignore BlockingIOErrors and EINTR. other errors are shown |
| # https://www.python.org/dev/peps/pep-0475. |
| if e.errno not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| except (select.error, socket.error) as e: |
| # this is for Python 2.x |
| # ignore BlockingIOErrors and EINTR. all errors are shown |
| # see also http://www.python.org/dev/peps/pep-3151/#select |
| if e[0] not in (errno.EAGAIN, errno.EALREADY, errno.EWOULDBLOCK, errno.EINPROGRESS, errno.EINTR): |
| raise SerialException('read failed: {}'.format(e)) |
| |
| def reset_output_buffer(self): |
| """\ |
| Clear output buffer, aborting the current output and |
| discarding all that is in the buffer. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('ignored reset_output_buffer') |
| |
| def send_break(self, duration=0.25): |
| """\ |
| Send break condition. Timed, returns to idle state after given |
| duration. |
| """ |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('ignored send_break({!r})'.format(duration)) |
| |
| def _update_break_state(self): |
| """Set break: Controls TXD. When active, to transmitting is |
| possible.""" |
| if self.logger: |
| self.logger.info('ignored _update_break_state({!r})'.format(self._break_state)) |
| |
| def _update_rts_state(self): |
| """Set terminal status line: Request To Send""" |
| if self.logger: |
| self.logger.info('ignored _update_rts_state({!r})'.format(self._rts_state)) |
| |
| def _update_dtr_state(self): |
| """Set terminal status line: Data Terminal Ready""" |
| if self.logger: |
| self.logger.info('ignored _update_dtr_state({!r})'.format(self._dtr_state)) |
| |
| @property |
| def cts(self): |
| """Read terminal status line: Clear To Send""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('returning dummy for cts') |
| return True |
| |
| @property |
| def dsr(self): |
| """Read terminal status line: Data Set Ready""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('returning dummy for dsr') |
| return True |
| |
| @property |
| def ri(self): |
| """Read terminal status line: Ring Indicator""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('returning dummy for ri') |
| return False |
| |
| @property |
| def cd(self): |
| """Read terminal status line: Carrier Detect""" |
| if not self.is_open: |
| raise PortNotOpenError() |
| if self.logger: |
| self.logger.info('returning dummy for cd)') |
| return True |
| |
| # - - - platform specific - - - |
| |
| # works on Linux and probably all the other POSIX systems |
| def fileno(self): |
| """Get the file handle of the underlying socket for use with select""" |
| return self._socket.fileno() |
| |
| |
| # |
| # simple client test |
| if __name__ == '__main__': |
| import sys |
| s = Serial('socket://localhost:7000') |
| sys.stdout.write('{}\n'.format(s)) |
| |
| sys.stdout.write("write...\n") |
| s.write(b"hello\n") |
| s.flush() |
| sys.stdout.write("read: {}\n".format(s.read(5))) |
| |
| s.close() |
