Source code for bokeh.server.util

# 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

    from socket import socket

# External imports
from tornado import netutil

# Globals and constants

__all__ = (

# 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('', '') True >>> match_host('', '') True >>> match_host('', '') False >>> match_host('', '') False >>> match_host('', '192.168.*.*') True >>> match_host('alice', 'alice') True >>> match_host('alice:80', 'alice') True >>> match_host('alice', 'bob') False >>> match_host('', '') 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 #-----------------------------------------------------------------------------