You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
89 lines
2.8 KiB
Python
89 lines
2.8 KiB
Python
2 years ago
|
"""
|
||
|
|
wsproto/utilities
|
||
|
|
~~~~~~~~~~~~~~~~~
|
||
|
|
|
||
|
|
Utility functions that do not belong in a separate module.
|
||
|
|
"""
|
||
|
|
import base64
|
||
|
|
import hashlib
|
||
|
|
import os
|
||
|
|
from typing import Dict, List, Optional, Union
|
||
|
|
|
||
|
|
from h11._headers import Headers as H11Headers
|
||
|
|
|
||
|
|
from .events import Event
|
||
|
|
from .typing import Headers
|
||
|
|
|
||
|
|
# RFC6455, Section 1.3 - Opening Handshake
|
||
|
|
ACCEPT_GUID = b"258EAFA5-E914-47DA-95CA-C5AB0DC85B11"
|
||
|
|
|
||
|
|
|
||
|
|
class ProtocolError(Exception):
|
||
|
|
pass
|
||
|
|
|
||
|
|
|
||
|
|
class LocalProtocolError(ProtocolError):
|
||
|
|
"""Indicates an error due to local/programming errors.
|
||
|
|
|
||
|
|
This is raised when the connection is asked to do something that
|
||
|
|
is either incompatible with the state or the websocket standard.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
pass # noqa
|
||
|
|
|
||
|
|
|
||
|
|
class RemoteProtocolError(ProtocolError):
|
||
|
|
"""Indicates an error due to the remote's actions.
|
||
|
|
|
||
|
|
This is raised when processing the bytes from the remote if the
|
||
|
|
remote has sent data that is incompatible with the websocket
|
||
|
|
standard.
|
||
|
|
|
||
|
|
.. attribute:: event_hint
|
||
|
|
|
||
|
|
This is a suggested wsproto Event to send to the client based
|
||
|
|
on the error. It could be None if no hint is available.
|
||
|
|
|
||
|
|
"""
|
||
|
|
|
||
|
|
def __init__(self, message: str, event_hint: Optional[Event] = None) -> None:
|
||
|
|
self.event_hint = event_hint
|
||
|
|
super().__init__(message)
|
||
|
|
|
||
|
|
|
||
|
|
# Some convenience utilities for working with HTTP headers
|
||
|
|
def normed_header_dict(h11_headers: Union[Headers, H11Headers]) -> Dict[bytes, bytes]:
|
||
|
|
# This mangles Set-Cookie headers. But it happens that we don't care about
|
||
|
|
# any of those, so it's OK. For every other HTTP header, if there are
|
||
|
|
# multiple instances then you're allowed to join them together with
|
||
|
|
# commas.
|
||
|
|
name_to_values: Dict[bytes, List[bytes]] = {}
|
||
|
|
for name, value in h11_headers:
|
||
|
|
name_to_values.setdefault(name, []).append(value)
|
||
|
|
name_to_normed_value = {}
|
||
|
|
for name, values in name_to_values.items():
|
||
|
|
name_to_normed_value[name] = b", ".join(values)
|
||
|
|
return name_to_normed_value
|
||
|
|
|
||
|
|
|
||
|
|
# We use this for parsing the proposed protocol list, and for parsing the
|
||
|
|
# proposed and accepted extension lists. For the proposed protocol list it's
|
||
|
|
# fine, because the ABNF is just 1#token. But for the extension lists, it's
|
||
|
|
# wrong, because those can contain quoted strings, which can in turn contain
|
||
|
|
# commas. XX FIXME
|
||
|
|
def split_comma_header(value: bytes) -> List[str]:
|
||
|
|
return [piece.decode("ascii").strip() for piece in value.split(b",")]
|
||
|
|
|
||
|
|
|
||
|
|
def generate_nonce() -> bytes:
|
||
|
|
# os.urandom may be overkill for this use case, but I don't think this
|
||
|
|
# is a bottleneck, and better safe than sorry...
|
||
|
|
return base64.b64encode(os.urandom(16))
|
||
|
|
|
||
|
|
|
||
|
|
def generate_accept_token(token: bytes) -> bytes:
|
||
|
|
accept_token = token + ACCEPT_GUID
|
||
|
|
accept_token = hashlib.sha1(accept_token).digest()
|
||
|
|
return base64.b64encode(accept_token)
|