b34a8c1f73
- Adds tests for correctness of tokenizer (which also would have shown shlex wouldn't have worked). - Should conform with the original's behavior, though we won't be able to match the error messages without a lot of extra work as a non-regexp version is likely a no go on python due to speed.
136 lines
4.4 KiB
Python
136 lines
4.4 KiB
Python
"""
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This is Mopidy's MPD protocol implementation.
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This is partly based upon the `MPD protocol documentation
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<http://www.musicpd.org/doc/protocol/>`_, which is a useful resource, but it is
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rather incomplete with regards to data formats, both for requests and
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responses. Thus, we have had to talk a great deal with the the original `MPD
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server <http://mpd.wikia.com/>`_ using telnet to get the details we need to
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implement our own MPD server which is compatible with the numerous existing
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`MPD clients <http://mpd.wikia.com/wiki/Clients>`_.
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"""
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from __future__ import unicode_literals
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from collections import namedtuple
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import re
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from mopidy.utils import formatting
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#: The MPD protocol uses UTF-8 for encoding all data.
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ENCODING = 'UTF-8'
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#: The MPD protocol uses ``\n`` as line terminator.
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LINE_TERMINATOR = '\n'
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#: The MPD protocol version is 0.17.0.
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VERSION = '0.17.0'
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MpdCommand = namedtuple('MpdCommand', ['name', 'auth_required'])
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#: Set of all available commands, represented as :class:`MpdCommand` objects.
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mpd_commands = set()
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#: Map between request matchers and request handler functions.
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request_handlers = {}
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def handle_request(pattern, auth_required=True):
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"""
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Decorator for connecting command handlers to command requests.
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If you use named groups in the pattern, the decorated method will get the
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groups as keyword arguments. If the group is optional, remember to give the
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argument a default value.
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For example, if the command is ``do that thing`` the ``what`` argument will
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be ``this thing``::
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@handle_request('do\ (?P<what>.+)$')
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def do(what):
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...
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Note that the patterns are compiled with the :attr:`re.VERBOSE` flag. Thus,
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you must escape any space characters you want to match, but you're also
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free to add non-escaped whitespace to format the pattern for easier
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reading.
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:param pattern: regexp pattern for matching commands
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:type pattern: string
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"""
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def decorator(func):
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match = re.search('([a-z_]+)', pattern)
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if match is not None:
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mpd_commands.add(
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MpdCommand(name=match.group(), auth_required=auth_required))
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compiled_pattern = re.compile(pattern, flags=(re.UNICODE | re.VERBOSE))
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if compiled_pattern in request_handlers:
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raise ValueError('Tried to redefine handler for %s with %s' % (
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pattern, func))
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request_handlers[compiled_pattern] = func
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func.__doc__ = """
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*Pattern:*
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.. code-block:: text
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%(pattern)s
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%(docs)s
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""" % {
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'pattern': formatting.indent(pattern, places=8, singles=True),
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'docs': func.__doc__ or '',
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}
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return func
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return decorator
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def load_protocol_modules():
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"""
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The protocol modules must be imported to get them registered in
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:attr:`request_handlers` and :attr:`mpd_commands`.
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"""
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from . import ( # noqa
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audio_output, channels, command_list, connection, current_playlist,
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empty, music_db, playback, reflection, status, stickers,
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stored_playlists)
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WORD_RE = re.compile(r"""
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^ # Leading whitespace is not allowed
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([a-z][a-z0-9_]*) # A command name
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(?:\s+|$) # trailing whitespace or EOS
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(.*) # Possibly a remainder to be parsed
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""", re.VERBOSE)
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# Quotes matching is an unrolled version of "(?:[^"\\]|\\.)*"
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PARAM_RE = re.compile(r"""
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^ # Leading whitespace is not allowed
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(?:
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([^%(unprintable)s"\\]+) # ord(char) < 0x20, not ", not backslash
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| # or
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"([^"\\]*(?:\\.[^"\\]*)*)" # anything surrounded by quotes
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)
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(?:\s+|$) # trailing whitespace or EOS
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(.*) # Possibly a remainder to be parsed
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""" % {'unprintable': ''.join(map(chr, range(0x21)))}, re.VERBOSE)
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UNESCAPE_RE = re.compile(r'\\(.)') # Backslash escapes any following char.
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# TODO: update exception usage and messages
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def tokenize(line):
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match = WORD_RE.match(line)
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if not match:
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raise Exception('Invalid command')
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command, remainder = match.groups()
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result = [command]
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while remainder:
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match = PARAM_RE.match(remainder)
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if not match:
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raise Exception('Invalid parameter')
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unquoted, quoted, remainder = match.groups()
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result.append(unquoted or UNESCAPE_RE.sub(r'\g<1>', quoted))
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return result
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