From ef30201a99c6aeb9bf2406904005f0977f1c4ecc Mon Sep 17 00:00:00 2001 From: Christophe Besson Date: Sat, 15 Aug 2026 19:13:30 +0200 Subject: docs: record which download paths have actually been run MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The download-to-disk story is three mechanisms — File System Access in Chrome, a service worker streaming a response in Firefox and Safari, a blob as the floor — and no test in this repository exercises any of them. test_downloads.py pins their contracts by reading the source; whether a browser really writes to disk needs a person with a large file. One now has: Firefox, 180 MB, written to disk rather than assembled in the tab. That is the path worth confirming, since it is the only one Firefox has and it was written blind. It is also not the scale it exists for, and the guide says which rows of that table are measured and which are still only designed. Co-Authored-By: Claude Opus 5 --- docs/USERGUIDE.md | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'docs') diff --git a/docs/USERGUIDE.md b/docs/USERGUIDE.md index 8a55928..d6ce327 100644 --- a/docs/USERGUIDE.md +++ b/docs/USERGUIDE.md @@ -556,6 +556,21 @@ from a page. If even that is unavailable, a download under 512 MB is collected i memory and handed over; a larger one asks where to put it, because a tab does not survive a multi-gigabyte blob. +**What has been exercised**, as of 2026-08-15, so the next person knows which of +this is measured and which is designed: + +| Path | Browser | State | +|---|---|---| +| Streamed into a granted folder | Chrome | works | +| Streamed by the service worker | Firefox | works — 180 MB, written to disk | +| Collected in memory (no folder, no worker) | any | works, bounded at 512 MB | +| Save As for a download over 512 MB | Chrome | works | +| Multi-gigabyte download, any path | — | designed for, not yet measured | + +The 180 MB run is the one that matters most, because the service worker is the +only way Firefox writes a download to disk rather than building it in a tab. It +has not been tried at the scale it exists for. + A finished download offers **Open** in the transfers widget when it went into a folder you granted: the file is handed to a new tab and the browser decides what to do with it. That is the whole of what a web page can do here — it cannot start -- cgit v1.2.3