#-----------------------------------------------------------------------------
# Copyright (c) 2012 - 2022, Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
#-----------------------------------------------------------------------------
''' Provide some utility functions useful for implementing different
components in ``bokeh.server``.
'''
#-----------------------------------------------------------------------------
# Boilerplate
#-----------------------------------------------------------------------------
from __future__ import annotations
import logging # isort:skip
log = logging.getLogger(__name__)
#-----------------------------------------------------------------------------
# Imports
#-----------------------------------------------------------------------------
# Standard library imports
from typing import TYPE_CHECKING, Sequence
if TYPE_CHECKING:
from socket import socket
# External imports
from tornado import netutil
#-----------------------------------------------------------------------------
# Globals and constants
#-----------------------------------------------------------------------------
__all__ = (
'bind_sockets',
'check_allowlist',
'create_hosts_allowlist',
'match_host',
)
#-----------------------------------------------------------------------------
# General API
#-----------------------------------------------------------------------------
[docs]def bind_sockets(address: str | None, port: int) -> tuple[list[socket], int]:
''' Bind a socket to a port on an address.
Args:
address (str) :
An address to bind a port on, e.g. ``"localhost"``
port (int) :
A port number to bind.
Pass 0 to have the OS automatically choose a free port.
This function returns a 2-tuple with the new socket as the first element,
and the port that was bound as the second. (Useful when passing 0 as a port
number to bind any free port.)
Returns:
(socket, port)
'''
ss = netutil.bind_sockets(port=port or 0, address=address)
assert len(ss)
ports = {s.getsockname()[1] for s in ss}
assert len(ports) == 1, "Multiple ports assigned??"
actual_port = ports.pop()
if port:
assert actual_port == port
return ss, actual_port
[docs]def check_allowlist(host: str, allowlist: Sequence[str]) -> bool:
''' Check a given request host against a allowlist.
Args:
host (str) :
A host string to compare against a allowlist.
If the host does not specify a port, then ``":80"`` is implicitly
assumed.
allowlist (seq[str]) :
A list of host patterns to match against
Returns:
``True``, if ``host`` matches any pattern in ``allowlist``, otherwise
``False``
'''
if ':' not in host:
host = host + ':80'
if host in allowlist:
return True
return any(match_host(host, pattern) for pattern in allowlist)
[docs]def create_hosts_allowlist(host_list: Sequence[str] | None, port: int | None) -> list[str]:
'''
This allowlist can be used to restrict websocket or other connections to
only those explicitly originating from approved hosts.
Args:
host_list (seq[str]) :
A list of string `<name>` or `<name>:<port>` values to add to the
allowlist.
If no port is specified in a host string, then ``":80"`` is
implicitly assumed.
port (int) :
If ``host_list`` is empty or ``None``, then the allowlist will
be the single item list `` [ 'localhost:<port>' ]``
If ``host_list`` is not empty, this parameter has no effect.
Returns:
list[str]
Raises:
ValueError, if host or port values are invalid
Note:
If any host in ``host_list`` contains a wildcard ``*`` a warning will
be logged regarding permissive websocket connections.
'''
if not host_list:
return ['localhost:' + str(port)]
hosts: list[str] = []
for host in host_list:
if '*' in host:
log.warning(
"Host wildcard %r will allow connections originating "
"from multiple (or possibly all) hostnames or IPs. Use non-wildcard "
"values to restrict access explicitly", host)
if host == '*':
# do not append the :80 port suffix in that case: any port is
# accepted
hosts.append(host)
continue
parts = host.split(':')
if len(parts) == 1:
if parts[0] == "":
raise ValueError("Empty host value")
hosts.append(host+":80")
elif len(parts) == 2:
try:
int(parts[1])
except ValueError:
raise ValueError("Invalid port in host value: %s" % host)
if parts[0] == "":
raise ValueError("Empty host value")
hosts.append(host)
else:
raise ValueError("Invalid host value: %s" % host)
return hosts
[docs]def match_host(host: str, pattern: str) -> bool:
''' Match a host string against a pattern
Args:
host (str)
A hostname to compare to the given pattern
pattern (str)
A string representing a hostname pattern, possibly including
wildcards for ip address octets or ports.
This function will return ``True`` if the hostname matches the pattern,
including any wildcards. If the pattern contains a port, the host string
must also contain a matching port.
Returns:
bool
Examples:
>>> match_host('192.168.0.1:80', '192.168.0.1:80')
True
>>> match_host('192.168.0.1:80', '192.168.0.1')
True
>>> match_host('192.168.0.1:80', '192.168.0.1:8080')
False
>>> match_host('192.168.0.1', '192.168.0.2')
False
>>> match_host('192.168.0.1', '192.168.*.*')
True
>>> match_host('alice', 'alice')
True
>>> match_host('alice:80', 'alice')
True
>>> match_host('alice', 'bob')
False
>>> match_host('foo.example.com', 'foo.example.com.net')
False
>>> match_host('alice', '*')
True
>>> match_host('alice', '*:*')
True
>>> match_host('alice:80', '*')
True
>>> match_host('alice:80', '*:80')
True
>>> match_host('alice:8080', '*:80')
False
'''
host_port: str | None = None
if ':' in host:
host, host_port = host.rsplit(':', 1)
pattern_port: str | None = None
if ':' in pattern:
pattern, pattern_port = pattern.rsplit(':', 1)
if pattern_port == '*':
pattern_port = None
if pattern_port is not None and host_port != pattern_port:
return False
host_parts = host.split('.')
pattern_parts = pattern.split('.')
if len(pattern_parts) > len(host_parts):
return False
for h, p in zip(host_parts, pattern_parts):
if h == p or p == '*':
continue
else:
return False
return True
#-----------------------------------------------------------------------------
# Dev API
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Private API
#-----------------------------------------------------------------------------
#-----------------------------------------------------------------------------
# Code
#-----------------------------------------------------------------------------