moving to scripts

asq-env/lib/python3.9/site-packages/wsproto/utilities.py

@@ -0,0 +1,86 @@
+"""
+wsproto/utilities
+~~~~~~~~~~~~~~~~~
+
+Utility functions that do not belong in a separate module.
+"""
+import base64
+import hashlib
+import os
+from typing import Dict, List, Optional
+
+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: Headers) -> 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)