diff options
Diffstat (limited to 'packages/meshbay-node/src')
3 files changed, 113 insertions, 1 deletions
diff --git a/packages/meshbay-node/src/meshbay_node/__init__.py b/packages/meshbay-node/src/meshbay_node/__init__.py index 1bc8c9f..182ed32 100644 --- a/packages/meshbay-node/src/meshbay_node/__init__.py +++ b/packages/meshbay-node/src/meshbay_node/__init__.py @@ -1,3 +1,3 @@ """MeshBay Node — local file host, streaming server, and group daemon.""" -__version__ = "0.12.0" +__version__ = "0.13.0" diff --git a/packages/meshbay-node/src/meshbay_node/transfers.py b/packages/meshbay-node/src/meshbay_node/transfers.py index dd5da5c..2185547 100644 --- a/packages/meshbay-node/src/meshbay_node/transfers.py +++ b/packages/meshbay-node/src/meshbay_node/transfers.py @@ -403,3 +403,86 @@ class TransferSlots: return " ".join( f"{kind[0]}={p[kind]['in_use']}/{p[kind]['cap']}" f"(q{p[kind]['queued']})" for kind in KINDS) + + +# ── Reads that carry no lease ─────────────────────────────────────────────── + +# How many distinct files one session may be reading at once without a lease. +# +# Browsing a group is never subject to a transfer slot — not the poster grid, +# not the covers, not opening a photo or a PDF to look at it. A member must be +# able to browse a group that is at capacity exactly as they browse an idle one. +# That is a requirement, and §3.4 of ~/next/improve-downloads.md satisfies it +# structurally: a transfer is what the transfers widget shows, and nothing else +# takes a slot. +# +# But "not leased" cannot mean "unbounded", or a client that simply omits `tr` +# transfers outside every cap and the caps are decoration. Two, because a viewer +# looks at *one* file — one photo, one document — and the second is there so +# that prefetching the next photo stays possible. +# +# Deliberately a count of files and not a byte budget: a RAW photo out of a +# camera is 60-80 MB and is browsing, a 40 MB archive is a download, and no +# size threshold separates them. What separates them is which function asked. +# +# What it costs, stated plainly: a client that lies — labelling a bulk download +# as a view — gets two files at a time instead of its member cap. That is the +# residual, it is bounded, it is audited, and it is the same kind of statement +# as the cap itself. **This is a fairness control among cooperating clients**, +# not a defence against a member determined to saturate a node's disk. The +# answer to that member is `member revoke`. +MAX_LEASELESS_IN_FLIGHT = 2 + +# A leaseless read has no "close" message, so it ends when the last chunk goes +# out — or, when a viewer is closed mid-file and simply stops asking, when it +# has been quiet this long. +LEASELESS_IDLE_SECS = 60 + + +class LeaselessReads: + """ + The files one session is reading without a lease, and the bound on them. + + Per session rather than per member: this is not a resource pool, it is a + ceiling on what one connection can do while claiming to be browsing. A + member with three tabs open is browsing in three tabs, which is fine. + """ + + def __init__(self, limit: int = MAX_LEASELESS_IN_FLIGHT, + idle: float = LEASELESS_IDLE_SECS) -> None: + self.limit = limit + self.idle = idle + self._seen: dict[str, float] = {} + + def admit(self, file_id: str, now: float | None = None) -> bool: + """May this session read `file_id` without a lease right now? + + True for a file it is already reading, whatever the count: refusing a + chunk halfway through a photo because the limit moved would be worse + than never having admitted it. + """ + when = time.monotonic() if now is None else now + self._expire(when) + if file_id in self._seen: + self._seen[file_id] = when + return True + if len(self._seen) >= self.limit: + return False + self._seen[file_id] = when + return True + + def finish(self, file_id: str) -> None: + """The last chunk went out; the slot is free at once rather than in a + minute.""" + self._seen.pop(file_id, None) + + def _expire(self, now: float) -> None: + # A viewer closed mid-file stops asking and says nothing. Without this + # the session would carry two dead entries and refuse every later + # preview, which is the bound turning into a bug. + for file_id, last in list(self._seen.items()): + if now - last > self.idle: + del self._seen[file_id] + + def __len__(self) -> int: + return len(self._seen) diff --git a/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py b/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py index 9de799c..507650a 100644 --- a/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py +++ b/packages/meshbay-node/src/meshbay_node/transport/webrtc_server.py @@ -430,6 +430,11 @@ class WebRTCPeerSession: self._admin_ops: dict[str, dict] = {} # op_id → pending admin operation # Uploads in progress live in the group context, not here: see # `_partial_uploads` and `uploads.py`. + # + # Leaseless reads, though, *are* this connection's: the bound is on what + # one session may do while claiming to be browsing, not a pool shared + # between them. Three tabs open is browsing in three tabs. + self._leaseless = transfers_mod.LeaselessReads() # Diagnostics only (_WEBRTC_TRACE): when the last DataChannel message # arrived, so the heartbeat can report silence duration. self._last_msg_at: float = 0.0 @@ -3689,6 +3694,25 @@ class WebRTCPeerSession: self._send({"type": "error", "detail": "File not on disk"}) return + # A real index entry, asked for without a lease: browsing, or a client + # helping itself to the whole library outside every cap. + # + # Both look identical here — which is why the bound is a small count of + # files rather than a judgement about what the read is for. Thumbnails, + # posters and cover art never reach this line: they resolve through + # `_try_serve_thumbnail` above, out of a cache the node built itself, + # and are never leased, never counted, never queued. + if not tr: + if not self._leaseless.admit(str(file_id)): + self._send({ + "type": "error", + "detail": "Too many files open at once without a transfer. " + "Download this one instead of previewing it.", + "code": "transfer_required", + "file_id": file_id, + }) + return + log.debug("dl: req file=%s chunk=%s buffered=%s", file_id[:12], chunk_index, getattr(self._channel, "bufferedAmount", "?")) @@ -3713,6 +3737,11 @@ class WebRTCPeerSession: getattr(self._channel, "bufferedAmount", "?")) if chunk_index == 0: self._audit("file_download", entry.name) + # The last chunk is the only "close" a leaseless read has. Without this + # the session carries the entry until it goes idle, and the person who + # just looked at two photos cannot look at a third for a minute. + if not tr and (chunk_index + 1) * CHUNK_SIZE >= entry.size: + self._leaseless.finish(str(file_id)) @staticmethod async def _fetch_and_cache_poster(media_cache, tmdb_client, poster_path: str | None) -> str | None: |