55 lines
1.6 KiB
Python
55 lines
1.6 KiB
Python
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import random
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import time
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CODE_LENGTH = 6
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CODE_TTL_SECONDS = 600
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PENDING_MAX = 3
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RATE_LIMIT_SECONDS = 3600
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CODE_CHARS = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789"
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class WebhookPairing:
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def __init__(self):
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self._pending: dict[str, dict] = {}
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self._sender_last_code_at: dict[str, float] = {}
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def generate_code(self, sender_id: str) -> str | None:
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now = time.time()
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now_mono = time.monotonic()
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if sender_id in self._sender_last_code_at:
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if now - self._sender_last_code_at[sender_id] < RATE_LIMIT_SECONDS:
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return None
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self._evict_if_full(now_mono)
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code = "".join(random.choices(CODE_CHARS, k=CODE_LENGTH))
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self._pending[sender_id] = {"code": code, "created_at": now_mono}
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self._sender_last_code_at[sender_id] = now
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return code
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def verify(self, sender_id: str, code: str) -> bool:
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entry = self._pending.get(sender_id)
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if not entry:
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return False
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if time.monotonic() - entry["created_at"] > CODE_TTL_SECONDS:
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del self._pending[sender_id]
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return False
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if entry["code"] != code.upper().strip():
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return False
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del self._pending[sender_id]
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return True
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def _evict_if_full(self, now: float):
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if len(self._pending) < PENDING_MAX:
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return
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oldest = min(self._pending.values(), key=lambda p: p["created_at"])
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if now - oldest["created_at"] < CODE_TTL_SECONDS:
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return
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expired_key = next(k for k, v in self._pending.items() if v == oldest)
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del self._pending[expired_key]
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