Stem Docs

stem.util.tor_tools

Source code for stem.util.tor_tools

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

"""
Miscellaneous utility functions for working with tor.

.. versionadded:: 1.2.0

**Module Overview:**

::

  is_valid_fingerprint - checks if a string is a valid tor relay fingerprint
  is_valid_nickname - checks if a string is a valid tor relay nickname
  is_valid_circuit_id - checks if a string is a valid tor circuit id
  is_valid_stream_id - checks if a string is a valid tor stream id
  is_valid_connection_id - checks if a string is a valid tor connection id
  is_valid_hidden_service_address - checks if a string is a valid hidden service address
  is_hex_digits - checks if a string is only made up of hex digits
"""

import re

import stem.util.str_tools

# The control-spec defines the following as...
#
#   Fingerprint = "$" 40*HEXDIG
#   NicknameChar = "a"-"z" / "A"-"Z" / "0" - "9"
#   Nickname = 1*19 NicknameChar
#
#   CircuitID = 1*16 IDChar
#   IDChar = ALPHA / DIGIT
#
# HEXDIG is defined in RFC 5234 as being uppercase and used in RFC 5987 as
# case insensitive. Tor doesn't define this in the spec so flipping a coin
# and going with case insensitive.

NICKNAME_PATTERN = re.compile('^[a-zA-Z0-9]{1,19}$')
CIRC_ID_PATTERN = re.compile('^[a-zA-Z0-9]{1,16}$')

# Hidden service addresses are sixteen base32 characters.

HS_ADDRESS_PATTERN = re.compile('^[a-z2-7]{16}$')


[docs]def is_valid_fingerprint(entry, check_prefix = False): """ Checks if a string is a properly formatted relay fingerprint. This checks for a '$' prefix if check_prefix is true, otherwise this only validates the hex digits. :param str entry: string to be checked :param bool check_prefix: checks for a '$' prefix :returns: **True** if the string could be a relay fingerprint, **False** otherwise """ if isinstance(entry, bytes): entry = stem.util.str_tools._to_unicode(entry) try: if check_prefix: if not entry or entry[0] != '$': return False entry = entry[1:] return is_hex_digits(entry, 40) except TypeError: return False
[docs]def is_valid_nickname(entry): """ Checks if a string is a valid format for being a nickname. :param str entry: string to be checked :returns: **True** if the string could be a nickname, **False** otherwise """ if isinstance(entry, bytes): entry = stem.util.str_tools._to_unicode(entry) try: return bool(NICKNAME_PATTERN.match(entry)) except TypeError: return False
[docs]def is_valid_circuit_id(entry): """ Checks if a string is a valid format for being a circuit identifier. :returns: **True** if the string could be a circuit id, **False** otherwise """ if isinstance(entry, bytes): entry = stem.util.str_tools._to_unicode(entry) try: return bool(CIRC_ID_PATTERN.match(entry)) except TypeError: return False
[docs]def is_valid_stream_id(entry): """ Checks if a string is a valid format for being a stream identifier. Currently, this is just an alias to :func:`~stem.util.tor_tools.is_valid_circuit_id`. :returns: **True** if the string could be a stream id, **False** otherwise """ return is_valid_circuit_id(entry)
[docs]def is_valid_connection_id(entry): """ Checks if a string is a valid format for being a connection identifier. Currently, this is just an alias to :func:`~stem.util.tor_tools.is_valid_circuit_id`. :returns: **True** if the string could be a connection id, **False** otherwise """ return is_valid_circuit_id(entry)
[docs]def is_valid_hidden_service_address(entry): """ Checks if a string is a valid format for being a hidden service address (not including the '.onion' suffix). :returns: **True** if the string could be a hidden service address, **False** otherwise """ if isinstance(entry, bytes): entry = stem.util.str_tools._to_unicode(entry) try: return bool(HS_ADDRESS_PATTERN.match(entry)) except TypeError: return False
[docs]def is_hex_digits(entry, count): """ Checks if a string is the given number of hex digits. Digits represented by letters are case insensitive. :param str entry: string to be checked :param int count: number of hex digits to be checked for :returns: **True** if the given number of hex digits, **False** otherwise """ try: if len(entry) != count: return False int(entry, 16) # attempt to convert it as hex return True except (ValueError, TypeError): return False