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# Copyright (c) 2018, Neil Booth
#
# All rights reserved.
#
# The MIT License (MIT)
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
__all__ = ('instantiate_coroutine', 'is_valid_hostname', 'classify_host',
'validate_port', 'validate_protocol', 'Service', 'ServicePart', 'NetAddress')
import asyncio
from collections import namedtuple
from enum import IntEnum
from functools import partial
import inspect
from ipaddress import ip_address, IPv4Address, IPv6Address
import re
# See http://stackoverflow.com/questions/2532053/validate-a-hostname-string
# Note underscores are valid in domain names, but strictly invalid in host
# names. We ignore that distinction.
PROTOCOL_REGEX = re.compile('[A-Za-z][A-Za-z0-9+-.]+$')
LABEL_REGEX = re.compile('^[a-z0-9_]([a-z0-9-_]{0,61}[a-z0-9_])?$', re.IGNORECASE)
NUMERIC_REGEX = re.compile('[0-9]+$')
def is_valid_hostname(hostname):
'''Return True if hostname is valid, otherwise False.'''
if not isinstance(hostname, str):
raise TypeError('hostname must be a string')
# strip exactly one dot from the right, if present
if hostname and hostname[-1] == ".":
hostname = hostname[:-1]
if not hostname or len(hostname) > 253:
return False
labels = hostname.split('.')
# the TLD must be not all-numeric
if re.match(NUMERIC_REGEX, labels[-1]):
return False
return all(LABEL_REGEX.match(label) for label in labels)
def classify_host(host):
'''Host is an IPv4Address, IPv6Address or a string.
If an IPv4Address or IPv6Address return it. Otherwise convert the string to an
IPv4Address or IPv6Address object if possible and return it. Otherwise return the
original string if it is a valid hostname.
Raise ValueError if a string cannot be interpreted as an IP address and it is not
a valid hostname.
'''
if isinstance(host, (IPv4Address, IPv6Address)):
return host
if is_valid_hostname(host):
return host
return ip_address(host)
def validate_port(port):
'''Validate port and return it as an integer.
A string, or its representation as an integer, is accepted.'''
if not isinstance(port, (str, int)):
raise TypeError(f'port must be an integer or string: {port}')
if isinstance(port, str) and port.isdigit():
port = int(port)
if isinstance(port, int) and 0 < port <= 65535:
return port
raise ValueError(f'invalid port: {port}')
def validate_protocol(protocol):
'''Validate a protocol, a string, and return it.'''
if not re.match(PROTOCOL_REGEX, protocol):
raise ValueError(f'invalid protocol: {protocol}')
return protocol.lower()
class ServicePart(IntEnum):
PROTOCOL = 0
HOST = 1
PORT = 2
def _split_address(string):
if string.startswith('['):
end = string.find(']')
if end != -1:
if len(string) == end + 1:
return string[1:end], ''
if string[end + 1] == ':':
return string[1:end], string[end+2:]
colon = string.find(':')
if colon == -1:
return string, ''
return string[:colon], string[colon + 1:]
class NetAddress:
def __init__(self, host, port):
'''Construct a NetAddress from a host and a port.
Host is classified and port is an integer.'''
self._host = classify_host(host)
self._port = validate_port(port)
def __eq__(self, other):
# pylint: disable=protected-access
return self._host == other._host and self._port == other._port
def __hash__(self):
return hash((self._host, self._port))
@classmethod
def from_string(cls, string, *, default_func=None):
'''Construct a NetAddress from a string and return a (host, port) pair.
If either (or both) is missing and default_func is provided, it is called with
ServicePart.HOST or ServicePart.PORT to get a default.
'''
if not isinstance(string, str):
raise TypeError(f'address must be a string: {string}')
host, port = _split_address(string)
if default_func:
host = host or default_func(ServicePart.HOST)
port = port or default_func(ServicePart.PORT)
if not host or not port:
raise ValueError(f'invalid address string: {string}')
return cls(host, port)
@property
def host(self):
return self._host
@property
def port(self):
return self._port
def __str__(self):
if isinstance(self._host, IPv6Address):
return f'[{self._host}]:{self._port}'
return f'{self.host}:{self.port}'
def __repr__(self):
return f'NetAddress({self.host!r}, {self.port})'
@classmethod
def default_host_and_port(cls, host, port):
def func(kind):
return host if kind == ServicePart.HOST else port
return func
@classmethod
def default_host(cls, host):
return cls.default_host_and_port(host, None)
@classmethod
def default_port(cls, port):
return cls.default_host_and_port(None, port)
class Service:
'''A validated protocol, address pair.'''
def __init__(self, protocol, address):
'''Construct a service from a protocol string and a NetAddress object,'''
self._protocol = validate_protocol(protocol)
if not isinstance(address, NetAddress):
address = NetAddress.from_string(address)
self._address = address
def __eq__(self, other):
# pylint: disable=protected-access
return self._protocol == other._protocol and self._address == other._address
def __hash__(self):
return hash((self._protocol, self._address))
@property
def protocol(self):
return self._protocol
@property
def address(self):
return self._address
@property
def host(self):
return self._address.host
@property
def port(self):
return self._address.port
@classmethod
def from_string(cls, string, *, default_func=None):
'''Construct a Service from a string.
If default_func is provided and any ServicePart is missing, it is called with
default_func(protocol, part) to obtain the missing part.
'''
if not isinstance(string, str):
raise TypeError(f'service must be a string: {string}')
parts = string.split('://', 1)
if len(parts) == 2:
protocol, address = parts
else:
item, = parts
protocol = None
if default_func:
if default_func(item, ServicePart.HOST) and default_func(item, ServicePart.PORT):
protocol, address = item, ''
else:
protocol, address = default_func(None, ServicePart.PROTOCOL), item
if not protocol:
raise ValueError(f'invalid service string: {string}')
if default_func:
default_func = partial(default_func, protocol.lower())
address = NetAddress.from_string(address, default_func=default_func)
return cls(protocol, address)
def __str__(self):
return f'{self._protocol}://{self._address}'
def __repr__(self):
return f"Service({self._protocol!r}, '{self._address}')"
def instantiate_coroutine(corofunc, args):
if asyncio.iscoroutine(corofunc):
if args != ():
raise ValueError('args cannot be passed with a coroutine')
return corofunc
return corofunc(*args)
def is_async_call(func):
'''inspect.iscoroutinefunction that looks through partials.'''
while isinstance(func, partial):
func = func.func
return inspect.iscoroutinefunction(func)
# other_params: None means cannot be called with keyword arguments only
# any means any name is good
SignatureInfo = namedtuple('SignatureInfo', 'min_args max_args '
'required_names other_names')
def signature_info(func):
params = inspect.signature(func).parameters
min_args = max_args = 0
required_names = []
other_names = []
no_names = False
for p in params.values():
if p.kind == p.POSITIONAL_OR_KEYWORD:
max_args += 1
if p.default is p.empty:
min_args += 1
required_names.append(p.name)
else:
other_names.append(p.name)
elif p.kind == p.KEYWORD_ONLY:
other_names.append(p.name)
elif p.kind == p.VAR_POSITIONAL:
max_args = None
elif p.kind == p.VAR_KEYWORD:
other_names = any
elif p.kind == p.POSITIONAL_ONLY:
max_args += 1
if p.default is p.empty:
min_args += 1
no_names = True
if no_names:
other_names = None
return SignatureInfo(min_args, max_args, required_names, other_names)
def check_task(logger, task):
if not task.cancelled():
try:
task.result()
except Exception: # pylint: disable=broad-except
logger.error('task crashed: %r', task, exc_info=True)
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