kaledonya clips: a Discord-friendly clip site on top of Zipline

Co-Authored-By: Claude Opus 5.5 <[email protected]>

intake/app/site_auth.py

@@ -0,0 +1,64 @@
+"""Login rate limit and one-time upload tickets for the clips site."""
+import secrets
+import time
+from collections import defaultdict, deque
+from collections.abc import Callable
+
+
+class LoginLimiter:
+    """At most `limit` failed logins per key (an IP) within `window` seconds."""
+
+    def __init__(self, limit: int = 5, window: float = 600, now: Callable[[], float] = time.monotonic):
+        self.limit, self.window, self.now = limit, window, now
+        self.fails: dict[str, deque] = defaultdict(deque)
+        self.swept = now()
+
+    def _recent(self, key: str) -> deque:
+        q, cutoff = self.fails[key], self.now() - self.window
+        while q and q[0] <= cutoff:
+            q.popleft()
+        return q
+
+    def blocked(self, key: str) -> bool:
+        if key not in self.fails:  # don't grow the table for every key that's merely checked
+            return False
+        return len(self._recent(key)) >= self.limit
+
+    def fail(self, key: str) -> None:
+        self._sweep()
+        self._recent(key).append(self.now())
+
+    def _sweep(self) -> None:
+        # forget keys whose strikes all expired, so guesses with made-up usernames can't grow the table forever
+        if self.now() - self.swept < self.window:
+            return
+        self.swept = self.now()
+        for key in [k for k in self.fails if not self._recent(k)]:
+            del self.fails[key]
+
+    def reset(self, key: str) -> None:
+        self.fails.pop(key, None)
+
+
+class TicketStore:
+    """One-time tickets that stand in for a Zipline token on /upload, valid `ttl` seconds."""
+
+    def __init__(self, ttl: float = 3600, now: Callable[[], float] = time.monotonic):
+        self.ttl, self.now = ttl, now
+        self.tickets: dict[str, tuple[str, float]] = {}
+
+    def _prune(self) -> None:
+        now = self.now()
+        for ticket in [t for t, (_, expires) in self.tickets.items() if expires <= now]:
+            del self.tickets[ticket]
+
+    def issue(self, token: str) -> str:
+        self._prune()
+        ticket = secrets.token_urlsafe(32)
+        self.tickets[ticket] = (token, self.now() + self.ttl)
+        return ticket
+
+    def redeem(self, ticket: str) -> str | None:
+        self._prune()
+        entry = self.tickets.pop(ticket, None)
+        return entry[0] if entry else None