| from __future__ import annotations |
|
|
| import base64 |
| import hashlib |
| import secrets |
| import sys |
|
|
| from .typing import BytesLike |
|
|
|
|
| __all__ = ["accept_key", "apply_mask"] |
|
|
|
|
| GUID = "258EAFA5-E914-47DA-95CA-C5AB0DC85B11" |
|
|
|
|
| def generate_key() -> str: |
| """ |
| Generate a random key for the Sec-WebSocket-Key header. |
| |
| """ |
| key = secrets.token_bytes(16) |
| return base64.b64encode(key).decode() |
|
|
|
|
| def accept_key(key: str) -> str: |
| """ |
| Compute the value of the Sec-WebSocket-Accept header. |
| |
| Args: |
| key: Value of the Sec-WebSocket-Key header. |
| |
| """ |
| sha1 = hashlib.sha1((key + GUID).encode()).digest() |
| return base64.b64encode(sha1).decode() |
|
|
|
|
| def apply_mask(data: BytesLike, mask: bytes | bytearray) -> bytes: |
| """ |
| Apply masking to the data of a WebSocket message. |
| |
| Args: |
| data: Data to mask. |
| mask: 4-bytes mask. |
| |
| """ |
| if len(mask) != 4: |
| raise ValueError("mask must contain 4 bytes") |
|
|
| data_int = int.from_bytes(data, sys.byteorder) |
| mask_repeated = mask * (len(data) // 4) + mask[: len(data) % 4] |
| mask_int = int.from_bytes(mask_repeated, sys.byteorder) |
| return (data_int ^ mask_int).to_bytes(len(data), sys.byteorder) |
|
|
