orrisroot
0cac30ccf8
The login cache is shared by every mdrs process, but the refresh was guarded by a lock that only reaches inside one. Concurrent runs each sent the same refresh token, and a provider that rotates them accepts the first and refuses the rest. - hold a lock that spans processes across the whole read-refresh- write, checking cheaply first so ordinary requests never take it - write the cache through a temporary file: opening it for writing truncates it, and a reader landing in that window found it empty and threw the session away - take the lock for every write, not just the refresh, so a login running beside one cannot be silently reverted - wait for a busy lock on Windows rather than giving up after the ten attempts msvcrt allows, and retry the rename it refuses while a reader still holds the file open - bound the refresh request on its own, so a provider that goes quiet cannot hold the lock indefinitely - accept bare hostnames such as localhost, store URLs without the trailing slash, and join download paths through one helper
46 lines
1.4 KiB
Python
46 lines
1.4 KiB
Python
import os
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import time
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from typing import IO, Any, Final
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from urllib.parse import parse_qs, urlparse
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if os.name == "nt":
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import msvcrt
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elif os.name == "posix":
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import fcntl
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class FileLock:
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# Long enough to outlast a token refresh, which is what the lock is held across.
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WAIT_SECONDS: Final[float] = 60.0
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@staticmethod
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def lock(file: IO[Any]) -> None:
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if os.name == "nt":
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# msvcrt.LK_LOCK gives up after ten one-second attempts, which is shorter
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# than the refresh it now has to wait for, so do the waiting here instead.
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deadline = time.monotonic() + FileLock.WAIT_SECONDS
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while True:
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try:
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msvcrt.locking(file.fileno(), msvcrt.LK_NBLCK, 1)
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return
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except OSError:
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if time.monotonic() >= deadline:
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raise
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time.sleep(0.1)
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elif os.name == "posix":
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fcntl.flock(file.fileno(), fcntl.LOCK_EX)
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@staticmethod
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def unlock(file: IO[Any]) -> None:
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if os.name == "nt":
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msvcrt.locking(file.fileno(), msvcrt.LK_UNLCK, 1)
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elif os.name == "posix":
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fcntl.flock(file.fileno(), fcntl.LOCK_UN)
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def page_num_from_url(url: str) -> int | None:
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parsed_url = urlparse(url)
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params = parse_qs(parsed_url.query)
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page = params.get("page", [None])[0]
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return int(page) if page is not None else None
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