Skyfay/SkySend v2.9.4

on GitHub

Service Worker Download Fixes for Firefox & Improved Caching

🐛 Bug Fixes

• web: Added try/catch around both crypto.subtle.decrypt calls in the Service Worker. An unauthenticated or corrupted encrypted record caused the decrypt call to throw, which rejected the pull() promise and let Firefox mark the download as completed with the incorrect partial file size. The stream is now explicitly errored via controller.error() and a dl-error broadcast is sent to the UI on failure.
• web: Added a cancelled flag to the Service Worker's cancel() handler, checked at every await boundary in pull(). Previously, calling cancel() while pull() was awaiting readMore() let pull() continue executing on an already-cancelled stream, which could reach controller.close() and throw.

🎨 Improvements

• web: Changed the Service Worker ReadableStream from highWaterMark: 0 to highWaterMark: 2 to address reported Firefox browser freezes during large-file downloads. With highWaterMark: 0, pull() is only triggered by a pending consumer read(), which may cause Firefox's download pipeline to block until a decrypted record is ready. With highWaterMark: 2, pull() runs proactively and keeps up to two pre-decrypted records in the internal queue, reducing the chance of a synchronous stall. pull() still enqueues exactly one record per call, so the stall-at-random-percentage behavior from v2.9.2 cannot recur.
• server: download-sw.js is now served with Cache-Control: no-cache, must-revalidate. Previously the file was served by the static file middleware with no explicit cache header, allowing browsers and intermediate proxies to apply heuristic caching. With no-cache, browsers byte-check the Service Worker file on every navigation and register any updated version immediately after a deployment, so users are never stuck running an outdated SW.
• web: Replaced the single-buffer copy strategy in the Service Worker ECE decryption pipeline with a zero-copy chunk queue. Previously appendToBuf() copied both the leftover bytes from the previous chunk (~65 KB) and the newly received chunk (~65 KB) into a fresh combined buffer on every pull() call - generating ~5 GB of unnecessary allocations for a 2.4 GB file. The new implementation pushes incoming reader.read() chunks into a queue by reference. readFromBuf() copies only the bytes required for the current decrypt call (one record, 65552 bytes), reducing GC pressure by roughly 2.5x and eliminating the speed oscillation and browser sluggishness during large downloads.
• web: Eliminated the per-record Uint8Array allocation in readFromBuf() by introducing a pre-allocated scratchRecord buffer (ENCRYPTED_RECORD_SIZE bytes) that is reused across all pull() calls. crypto.subtle.decrypt copies its input synchronously before returning the Promise, making the buffer safe to reuse as soon as the await resolves. This removes a further ~2.4 GB of GC-managed allocations per large file download, reducing peak heap pressure and Firefox RAM consumption.

🐳 Docker

• Image: skyfay/skysend:v2.9.4
• Also tagged as: latest, v2
• Platforms: linux/amd64, linux/arm64