292 lines
10 KiB
Python
292 lines
10 KiB
Python
#! python
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#
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# Python Serial Port Extension for Win32, Linux, BSD, Jython
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# see __init__.py
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#
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# This module implements a simple socket based client.
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# It does not support changing any port parameters and will silently ignore any
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# requests to do so.
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#
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# The purpose of this module is that applications using pySerial can connect to
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# TCP/IP to serial port converters that do not support RFC 2217.
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#
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# (C) 2001-2011 Chris Liechti <cliechti@gmx.net>
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# this is distributed under a free software license, see license.txt
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#
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# URL format: socket://<host>:<port>[/option[/option...]]
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# options:
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# - "debug" print diagnostic messages
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from serial.serialutil import *
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import time
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import socket
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import select
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import logging
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# map log level names to constants. used in fromURL()
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LOGGER_LEVELS = {
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'debug': logging.DEBUG,
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'info': logging.INFO,
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'warning': logging.WARNING,
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'error': logging.ERROR,
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}
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POLL_TIMEOUT = 2
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class SocketSerial(SerialBase):
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"""Serial port implementation for plain sockets."""
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BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
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9600, 19200, 38400, 57600, 115200)
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def open(self):
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"""\
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Open port with current settings. This may throw a SerialException
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if the port cannot be opened.
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"""
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self.logger = None
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if self._port is None:
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raise SerialException("Port must be configured before it can be used.")
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if self._isOpen:
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raise SerialException("Port is already open.")
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try:
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# XXX in future replace with create_connection (py >=2.6)
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self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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self._socket.connect(self.fromURL(self.portstr))
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except Exception, msg:
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self._socket = None
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raise SerialException("Could not open port %s: %s" % (self.portstr, msg))
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self._socket.settimeout(POLL_TIMEOUT) # used for write timeout support :/
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# not that there anything to configure...
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self._reconfigurePort()
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# all things set up get, now a clean start
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self._isOpen = True
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if not self._rtscts:
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self.setRTS(True)
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self.setDTR(True)
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self.flushInput()
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self.flushOutput()
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def _reconfigurePort(self):
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"""\
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Set communication parameters on opened port. For the socket://
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protocol all settings are ignored!
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"""
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if self._socket is None:
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raise SerialException("Can only operate on open ports")
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if self.logger:
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self.logger.info('ignored port configuration change')
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def close(self):
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"""Close port"""
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if self._isOpen:
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if self._socket:
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try:
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self._socket.shutdown(socket.SHUT_RDWR)
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self._socket.close()
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except:
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# ignore errors.
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pass
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self._socket = None
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self._isOpen = False
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# in case of quick reconnects, give the server some time
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time.sleep(0.3)
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def makeDeviceName(self, port):
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raise SerialException("there is no sensible way to turn numbers into URLs")
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def fromURL(self, url):
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"""extract host and port from an URL string"""
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if url.lower().startswith("socket://"): url = url[9:]
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try:
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# is there a "path" (our options)?
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if '/' in url:
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# cut away options
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url, options = url.split('/', 1)
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# process options now, directly altering self
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for option in options.split('/'):
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if '=' in option:
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option, value = option.split('=', 1)
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else:
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value = None
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if option == 'logging':
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logging.basicConfig() # XXX is that good to call it here?
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self.logger = logging.getLogger('pySerial.socket')
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self.logger.setLevel(LOGGER_LEVELS[value])
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self.logger.debug('enabled logging')
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else:
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raise ValueError('unknown option: %r' % (option,))
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# get host and port
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host, port = url.split(':', 1) # may raise ValueError because of unpacking
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port = int(port) # and this if it's not a number
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if not 0 <= port < 65536: raise ValueError("port not in range 0...65535")
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except ValueError, e:
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raise SerialException('expected a string in the form "[rfc2217://]<host>:<port>[/option[/option...]]": %s' % e)
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return (host, port)
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# - - - - - - - - - - - - - - - - - - - - - - - -
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def inWaiting(self):
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"""Return the number of characters currently in the input buffer."""
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if not self._isOpen: raise portNotOpenError
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# Poll the socket to see if it is ready for reading.
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# If ready, at least one byte will be to read.
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lr, lw, lx = select.select([self._socket], [], [], 0)
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return len(lr)
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def read(self, size=1):
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"""\
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Read size bytes from the serial port. If a timeout is set it may
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return less characters as requested. With no timeout it will block
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until the requested number of bytes is read.
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"""
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if not self._isOpen: raise portNotOpenError
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data = bytearray()
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if self._timeout is not None:
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timeout = time.time() + self._timeout
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else:
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timeout = None
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while len(data) < size and (timeout is None or time.time() < timeout):
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try:
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# an implementation with internal buffer would be better
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# performing...
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t = time.time()
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block = self._socket.recv(size - len(data))
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duration = time.time() - t
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if block:
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data.extend(block)
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else:
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# no data -> EOF (connection probably closed)
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break
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except socket.timeout:
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# just need to get out of recv from time to time to check if
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# still alive
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continue
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except socket.error, e:
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# connection fails -> terminate loop
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raise SerialException('connection failed (%s)' % e)
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return bytes(data)
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def write(self, data):
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"""\
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Output the given string over the serial port. Can block if the
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connection is blocked. May raise SerialException if the connection is
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closed.
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"""
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if not self._isOpen: raise portNotOpenError
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try:
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self._socket.sendall(to_bytes(data))
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except socket.error, e:
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# XXX what exception if socket connection fails
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raise SerialException("socket connection failed: %s" % e)
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return len(data)
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def flushInput(self):
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"""Clear input buffer, discarding all that is in the buffer."""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored flushInput')
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def flushOutput(self):
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"""\
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Clear output buffer, aborting the current output and
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discarding all that is in the buffer.
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"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored flushOutput')
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def sendBreak(self, duration=0.25):
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"""\
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Send break condition. Timed, returns to idle state after given
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duration.
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"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored sendBreak(%r)' % (duration,))
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def setBreak(self, level=True):
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"""Set break: Controls TXD. When active, to transmitting is
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possible."""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored setBreak(%r)' % (level,))
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def setRTS(self, level=True):
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"""Set terminal status line: Request To Send"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored setRTS(%r)' % (level,))
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def setDTR(self, level=True):
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"""Set terminal status line: Data Terminal Ready"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('ignored setDTR(%r)' % (level,))
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def getCTS(self):
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"""Read terminal status line: Clear To Send"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('returning dummy for getCTS()')
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return True
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def getDSR(self):
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"""Read terminal status line: Data Set Ready"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('returning dummy for getDSR()')
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return True
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def getRI(self):
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"""Read terminal status line: Ring Indicator"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('returning dummy for getRI()')
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return False
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def getCD(self):
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"""Read terminal status line: Carrier Detect"""
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if not self._isOpen: raise portNotOpenError
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if self.logger:
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self.logger.info('returning dummy for getCD()')
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return True
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# - - - platform specific - - -
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# works on Linux and probably all the other POSIX systems
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def fileno(self):
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"""Get the file handle of the underlying socket for use with select"""
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return self._socket.fileno()
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# assemble Serial class with the platform specific implementation and the base
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# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
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# library, derive from io.RawIOBase
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try:
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import io
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except ImportError:
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# classic version with our own file-like emulation
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class Serial(SocketSerial, FileLike):
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pass
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else:
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# io library present
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class Serial(SocketSerial, io.RawIOBase):
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pass
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# simple client test
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if __name__ == '__main__':
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import sys
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s = Serial('socket://localhost:7000')
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sys.stdout.write('%s\n' % s)
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sys.stdout.write("write...\n")
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s.write("hello\n")
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s.flush()
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sys.stdout.write("read: %s\n" % s.read(5))
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s.close()
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