92 lines
3.1 KiB
Python
92 lines
3.1 KiB
Python
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#! python
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#
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# This module implements a special URL handler that uses the port listing to
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# find ports by searching the string descriptions.
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#
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# This file is part of pySerial. https://github.com/pyserial/pyserial
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# (C) 2011-2015 Chris Liechti <cliechti@gmx.net>
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#
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# SPDX-License-Identifier: BSD-3-Clause
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#
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# URL format: hwgrep://<regexp>&<option>
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#
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# where <regexp> is a Python regexp according to the re module
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#
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# violating the normal definition for URLs, the charachter `&` is used to
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# separate parameters from the arguments (instead of `?`, but the question mark
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# is heavily used in regexp'es)
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#
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# options:
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# n=<N> pick the N'th entry instead of the first one (numbering starts at 1)
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# skip_busy tries to open port to check if it is busy, fails on posix as ports are not locked!
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from __future__ import absolute_import
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import serial
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import serial.tools.list_ports
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try:
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basestring
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except NameError:
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basestring = str # python 3 pylint: disable=redefined-builtin
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class Serial(serial.Serial):
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"""Just inherit the native Serial port implementation and patch the port property."""
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# pylint: disable=no-member
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@serial.Serial.port.setter
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def port(self, value):
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"""translate port name before storing it"""
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if isinstance(value, basestring) and value.startswith('hwgrep://'):
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serial.Serial.port.__set__(self, self.from_url(value))
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else:
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serial.Serial.port.__set__(self, value)
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def from_url(self, url):
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"""extract host and port from an URL string"""
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if url.lower().startswith("hwgrep://"):
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url = url[9:]
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n = 0
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test_open = False
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args = url.split('&')
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regexp = args.pop(0)
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for arg in args:
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if '=' in arg:
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option, value = arg.split('=', 1)
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else:
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option = arg
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value = None
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if option == 'n':
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# pick n'th element
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n = int(value) - 1
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if n < 1:
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raise ValueError('option "n" expects a positive integer larger than 1: {!r}'.format(value))
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elif option == 'skip_busy':
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# open to test if port is available. not the nicest way..
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test_open = True
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else:
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raise ValueError('unknown option: {!r}'.format(option))
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# use a for loop to get the 1st element from the generator
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for port, desc, hwid in sorted(serial.tools.list_ports.grep(regexp)):
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if test_open:
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try:
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s = serial.Serial(port)
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except serial.SerialException:
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# it has some error, skip this one
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continue
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else:
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s.close()
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if n:
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n -= 1
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continue
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return port
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else:
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raise serial.SerialException('no ports found matching regexp {!r}'.format(url))
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# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
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if __name__ == '__main__':
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s = Serial(None)
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s.port = 'hwgrep://ttyS0'
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print(s)
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