Stem Docs

stem.response

Source code for stem.response

# Copyright 2012-2017, Damian Johnson and The Tor Project
# See LICENSE for licensing information

"""
Parses replies from the control socket.

**Module Overview:**

::

  convert - translates a ControlMessage into a particular response subclass

  ControlMessage - Message that's read from the control socket.
    |- SingleLineResponse - Simple tor response only including a single line of information.
    |
    |- from_str - provides a ControlMessage for the given string
    |- is_ok - response had a 250 status
    |- content - provides the parsed message content
    |- raw_content - unparsed socket data
    |- __str__ - content stripped of protocol formatting
    +- __iter__ - ControlLine entries for the content of the message

  ControlLine - String subclass with methods for parsing controller responses.
    |- remainder - provides the unparsed content
    |- is_empty - checks if the remaining content is empty
    |- is_next_quoted - checks if the next entry is a quoted value
    |- is_next_mapping - checks if the next entry is a KEY=VALUE mapping
    |- peek_key - provides the key of the next entry
    |- pop - removes and returns the next entry
    +- pop_mapping - removes and returns the next entry as a KEY=VALUE mapping
"""

import codecs
import io
import re
import threading

import stem.socket
import stem.util.str_tools

__all__ = [
  'add_onion',
  'events',
  'getinfo',
  'getconf',
  'protocolinfo',
  'authchallenge',
  'convert',
  'ControlMessage',
  'ControlLine',
  'SingleLineResponse',
]

KEY_ARG = re.compile('^(\S+)=')


[docs]def convert(response_type, message, **kwargs): """ Converts a :class:`~stem.response.ControlMessage` into a particular kind of tor response. This does an in-place conversion of the message from being a :class:`~stem.response.ControlMessage` to a subclass for its response type. Recognized types include... =================== ===== response_type Class =================== ===== **ADD_ONION** :class:`stem.response.add_onion.AddOnionResponse` **AUTHCHALLENGE** :class:`stem.response.authchallenge.AuthChallengeResponse` **EVENT** :class:`stem.response.events.Event` subclass **GETCONF** :class:`stem.response.getconf.GetConfResponse` **GETINFO** :class:`stem.response.getinfo.GetInfoResponse` **MAPADDRESS** :class:`stem.response.mapaddress.MapAddressResponse` **PROTOCOLINFO** :class:`stem.response.protocolinfo.ProtocolInfoResponse` **SINGLELINE** :class:`stem.response.SingleLineResponse` =================== ===== :param str response_type: type of tor response to convert to :param stem.response.ControlMessage message: message to be converted :param kwargs: optional keyword arguments to be passed to the parser method :raises: * :class:`stem.ProtocolError` the message isn't a proper response of that type * :class:`stem.InvalidArguments` the arguments given as input are invalid, this is can only be raised if the response_type is: **GETINFO**, **GETCONF** * :class:`stem.InvalidRequest` the arguments given as input are invalid, this is can only be raised if the response_type is: **MAPADDRESS** * :class:`stem.OperationFailed` if the action the event represents failed, this is can only be raised if the response_type is: **MAPADDRESS** * **TypeError** if argument isn't a :class:`~stem.response.ControlMessage` or response_type isn't supported """ import stem.response.add_onion import stem.response.authchallenge import stem.response.events import stem.response.getinfo import stem.response.getconf import stem.response.mapaddress import stem.response.protocolinfo if not isinstance(message, ControlMessage): raise TypeError('Only able to convert stem.response.ControlMessage instances') response_types = { 'ADD_ONION': stem.response.add_onion.AddOnionResponse, 'AUTHCHALLENGE': stem.response.authchallenge.AuthChallengeResponse, 'EVENT': stem.response.events.Event, 'GETCONF': stem.response.getconf.GetConfResponse, 'GETINFO': stem.response.getinfo.GetInfoResponse, 'MAPADDRESS': stem.response.mapaddress.MapAddressResponse, 'PROTOCOLINFO': stem.response.protocolinfo.ProtocolInfoResponse, 'SINGLELINE': SingleLineResponse, } try: response_class = response_types[response_type] except TypeError: raise TypeError('Unsupported response type: %s' % response_type) message.__class__ = response_class message._parse_message(**kwargs)
[docs]class ControlMessage(object): """ Message from the control socket. This is iterable and can be stringified for individual message components stripped of protocol formatting. Messages are never empty. """ @staticmethod
[docs] def from_str(content, msg_type = None, normalize = False, **kwargs): """ Provides a ControlMessage for the given content. .. versionadded:: 1.1.0 .. versionchanged:: 1.6.0 Added the normalize argument. :param str content: message to construct the message from :param str msg_type: type of tor reply to parse the content as :param bool normalize: ensures expected carriage return and ending newline are present :param kwargs: optional keyword arguments to be passed to the parser method :returns: stem.response.ControlMessage instance """ if normalize: if not content.endswith('\n'): content += '\n' content = re.sub('([\r]?)\n', '\r\n', content) msg = stem.socket.recv_message(io.BytesIO(stem.util.str_tools._to_bytes(content))) if msg_type is not None: convert(msg_type, msg, **kwargs) return msg
def __init__(self, parsed_content, raw_content): if not parsed_content: raise ValueError("ControlMessages can't be empty") self._parsed_content = parsed_content self._raw_content = raw_content self._str = None
[docs] def is_ok(self): """ Checks if any of our lines have a 250 response. :returns: **True** if any lines have a 250 response code, **False** otherwise """ for code, _, _ in self._parsed_content: if code == '250': return True return False
[docs] def content(self, get_bytes = False): """ Provides the parsed message content. These are entries of the form... :: (status_code, divider, content) **status_code** Three character code for the type of response (defined in section 4 of the control-spec). **divider** Single character to indicate if this is mid-reply, data, or an end to the message (defined in section 2.3 of the control-spec). **content** The following content is the actual payload of the line. For data entries the content is the full multi-line payload with newline linebreaks and leading periods unescaped. The **status_code** and **divider** are both strings (**bytes** in python 2.x and **unicode** in python 3.x). The **content** however is **bytes** if **get_bytes** is **True**. .. versionchanged:: 1.1.0 Added the get_bytes argument. :param bool get_bytes: provides **bytes** for the **content** rather than a **str** :returns: **list** of (str, str, str) tuples for the components of this message """ if stem.prereq.is_python_3() and not get_bytes: return [(code, div, stem.util.str_tools._to_unicode(content)) for (code, div, content) in self._parsed_content] else: return list(self._parsed_content)
[docs] def raw_content(self, get_bytes = False): """ Provides the unparsed content read from the control socket. .. versionchanged:: 1.1.0 Added the get_bytes argument. :param bool get_bytes: if **True** then this provides **bytes** rather than a **str** :returns: **str** of the socket data used to generate this message """ if stem.prereq.is_python_3() and not get_bytes: return stem.util.str_tools._to_unicode(self._raw_content) else: return self._raw_content
def __str__(self): """ Content of the message, stripped of status code and divider protocol formatting. """ if self._str is None: self._str = '\n'.join(list(self)) return self._str def __iter__(self): """ Provides :class:`~stem.response.ControlLine` instances for the content of the message. This is stripped of status codes and dividers, for instance... :: 250+info/names= desc/id/* -- Router descriptors by ID. desc/name/* -- Router descriptors by nickname. . 250 OK Would provide two entries... :: 1st - "info/names= desc/id/* -- Router descriptors by ID. desc/name/* -- Router descriptors by nickname." 2nd - "OK" """ for _, _, content in self._parsed_content: if stem.prereq.is_python_3(): content = stem.util.str_tools._to_unicode(content) yield ControlLine(content) def __len__(self): """ :returns: number of ControlLines """ return len(self._parsed_content) def __getitem__(self, index): """ :returns: :class:`~stem.response.ControlLine` at the index """ content = self._parsed_content[index][2] if stem.prereq.is_python_3(): content = stem.util.str_tools._to_unicode(content) return ControlLine(content)
[docs]class ControlLine(str): """ String subclass that represents a line of controller output. This behaves as a normal string with additional methods for parsing and popping entries from a space delimited series of elements like a stack. None of these additional methods effect ourselves as a string (which is still immutable). All methods are thread safe. """ def __new__(self, value): return str.__new__(self, value) def __init__(self, value): self._remainder = value self._remainder_lock = threading.RLock()
[docs] def remainder(self): """ Provides our unparsed content. This is an empty string after we've popped all entries. :returns: **str** of the unparsed content """ return self._remainder
[docs] def is_empty(self): """ Checks if we have further content to pop or not. :returns: **True** if we have additional content, **False** otherwise """ return self._remainder == ''
[docs] def is_next_quoted(self, escaped = False): """ Checks if our next entry is a quoted value or not. :param bool escaped: unescapes the string :returns: **True** if the next entry can be parsed as a quoted value, **False** otherwise """ start_quote, end_quote = _get_quote_indices(self._remainder, escaped) return start_quote == 0 and end_quote != -1
[docs] def is_next_mapping(self, key = None, quoted = False, escaped = False): """ Checks if our next entry is a KEY=VALUE mapping or not. :param str key: checks that the key matches this value, skipping the check if **None** :param bool quoted: checks that the mapping is to a quoted value :param bool escaped: unescapes the string :returns: **True** if the next entry can be parsed as a key=value mapping, **False** otherwise """ remainder = self._remainder # temp copy to avoid locking key_match = KEY_ARG.match(remainder) if key_match: if key and key != key_match.groups()[0]: return False if quoted: # checks that we have a quoted value and that it comes after the 'key=' start_quote, end_quote = _get_quote_indices(remainder, escaped) return start_quote == key_match.end() and end_quote != -1 else: return True # we just needed to check for the key else: return False # doesn't start with a key
[docs] def peek_key(self): """ Provides the key of the next entry, providing **None** if it isn't a key/value mapping. :returns: **str** with the next entry's key """ remainder = self._remainder key_match = KEY_ARG.match(remainder) if key_match: return key_match.groups()[0] else: return None
[docs] def pop(self, quoted = False, escaped = False): """ Parses the next space separated entry, removing it and the space from our remaining content. Examples... :: >>> line = ControlLine("\\"We're all mad here.\\" says the grinning cat.") >>> print line.pop(True) "We're all mad here." >>> print line.pop() "says" >>> print line.remainder() "the grinning cat." >>> line = ControlLine("\\"this has a \\\\\\" and \\\\\\\\ in it\\" foo=bar more_data") >>> print line.pop(True, True) "this has a \\" and \\\\ in it" :param bool quoted: parses the next entry as a quoted value, removing the quotes :param bool escaped: unescapes the string :returns: **str** of the next space separated entry :raises: * **ValueError** if quoted is True without the value being quoted * **IndexError** if we don't have any remaining content left to parse """ with self._remainder_lock: next_entry, remainder = _parse_entry(self._remainder, quoted, escaped, False) self._remainder = remainder return next_entry
[docs] def pop_mapping(self, quoted = False, escaped = False, get_bytes = False): """ Parses the next space separated entry as a KEY=VALUE mapping, removing it and the space from our remaining content. .. versionchanged:: 1.6.0 Added the get_bytes argument. :param bool quoted: parses the value as being quoted, removing the quotes :param bool escaped: unescapes the string :param bool get_bytes: provides **bytes** for the **value** rather than a **str** :returns: **tuple** of the form (key, value) :raises: **ValueError** if this isn't a KEY=VALUE mapping or if quoted is **True** without the value being quoted :raises: **IndexError** if there's nothing to parse from the line """ with self._remainder_lock: if self.is_empty(): raise IndexError('no remaining content to parse') key_match = KEY_ARG.match(self._remainder) if not key_match: raise ValueError("the next entry isn't a KEY=VALUE mapping: " + self._remainder) # parse off the key key = key_match.groups()[0] remainder = self._remainder[key_match.end():] next_entry, remainder = _parse_entry(remainder, quoted, escaped, get_bytes) self._remainder = remainder return (key, next_entry)
def _parse_entry(line, quoted, escaped, get_bytes): """ Parses the next entry from the given space separated content. :param str line: content to be parsed :param bool quoted: parses the next entry as a quoted value, removing the quotes :param bool escaped: unescapes the string :returns: **tuple** of the form (entry, remainder) :raises: * **ValueError** if quoted is True without the next value being quoted * **IndexError** if there's nothing to parse from the line """ if line == '': raise IndexError('no remaining content to parse') next_entry, remainder = '', line if quoted: # validate and parse the quoted value start_quote, end_quote = _get_quote_indices(remainder, escaped) if start_quote != 0 or end_quote == -1: raise ValueError("the next entry isn't a quoted value: " + line) next_entry, remainder = remainder[1:end_quote], remainder[end_quote + 1:] else: # non-quoted value, just need to check if there's more data afterward if ' ' in remainder: next_entry, remainder = remainder.split(' ', 1) else: next_entry, remainder = remainder, '' if escaped: # Tor does escaping in its 'esc_for_log' function of 'common/util.c'. It's # hard to tell what controller functions use this in practice, but direct # users are... # # * 'COOKIEFILE' field of PROTOCOLINFO responses # * logged messages about bugs # * the 'getinfo_helper_listeners' function of control.c # # Ideally we'd use "next_entry.decode('string_escape')" but it was removed # in python 3.x and 'unicode_escape' isn't quite the same... # # https://stackoverflow.com/questions/14820429/how-do-i-decodestring-escape-in-python3 next_entry = codecs.escape_decode(next_entry)[0] if stem.prereq.is_python_3() and not get_bytes: next_entry = stem.util.str_tools._to_unicode(next_entry) # normalize back to str if get_bytes: next_entry = stem.util.str_tools._to_bytes(next_entry) return (next_entry, remainder.lstrip()) def _get_quote_indices(line, escaped): """ Provides the indices of the next two quotes in the given content. :param str line: content to be parsed :param bool escaped: unescapes the string :returns: **tuple** of two ints, indices being -1 if a quote doesn't exist """ indices, quote_index = [], -1 for _ in range(2): quote_index = line.find('"', quote_index + 1) # if we have escapes then we need to skip any r'\"' entries if escaped: # skip check if index is -1 (no match) or 0 (first character) while quote_index >= 1 and line[quote_index - 1] == '\\': quote_index = line.find('"', quote_index + 1) indices.append(quote_index) return tuple(indices)
[docs]class SingleLineResponse(ControlMessage): """ Reply to a request that performs an action rather than querying data. These requests only contain a single line, which is 'OK' if successful, and a description of the problem if not. :var str code: status code for our line :var str message: content of the line """
[docs] def is_ok(self, strict = False): """ Checks if the response code is "250". If strict is **True** then this checks if the response is "250 OK" :param bool strict: checks for a "250 OK" message if **True** :returns: * If strict is **False**: **True** if the response code is "250", **False** otherwise * If strict is **True**: **True** if the response is "250 OK", **False** otherwise """ if strict: return self.content()[0] == ('250', ' ', 'OK') return self.content()[0][0] == '250'
def _parse_message(self): content = self.content() if len(content) > 1: raise stem.ProtocolError('Received multi-line response') elif len(content) == 0: raise stem.ProtocolError('Received empty response') else: self.code, _, self.message = content[0]