FileThumbnailController::preview() writes at most one FilePreviewed row per viewer per file per five minutes, because watching a video is a single deliberate act that the browser turns into dozens of Range requests. Its docblock ended by naming the route where the same act happens without an account -- PublicGroupsController::preview -- and that route logged unconditionally. Five requests for the same public file wrote five rows where the signed-in twin wrote one, so one visitor watching one clip buried the public half of the activity log, which is the half an operator reads to see what the outside world is doing.
The window moves into a shared PreviewLog, next to PreviewKind, which those two routes already share for the same reason. Keying is unchanged for a signed-in viewer. An anonymous visitor has no account to key on, so the request IP stands in -- the same substitute ApiServiceProvider's rate limiter makes for an unauthenticated caller. It is a cache key with a five-minute life and never reaches the log, which keeps its own decision about recording an IP.
Downloads are deliberately untouched and stay one row per download: each is a transfer, and DownloadAllowance::used() counts those rows to enforce a per-file cap, so swallowing one would hand out free downloads.
The limit this leaves open, since the IP is a stand-in and not an identity: two anonymous visitors behind one address share a key, so within five minutes the second one's view of the same file is not recorded. That is the same trade the signed-in side has always made per account, and the alternative is the row-per-Range-request this fixes.
Verified before merging: 24 passed across the public-preview and thumbnail suites on the trial-merge, which also confirms this co-exists with #1725 -- the two share both controllers and change different methods in each. With app/ reset and PreviewLog deleted, 1 failed / 9 passed. The signed-in route's existing debounce tests pass unchanged, which is what says the shared class did not move that side. request()->ip() honours the trusted-proxy configuration, so a forged X-Forwarded-For cannot defeat the window from outside.
Reported and fixed by @denkfabrik-li.
Both thumbnail routes treat "the file exists" as "the rendition is
cached", and nothing ever invalidates one: RenderedImageCache::flush()
runs on ImageRenderingChanged, which no core code raises. Whatever is at
the path is what every later viewer gets.
ThumbnailGenerator encoded straight onto that path. A render that died
partway -- a full volume, a killed worker -- left a half-written file
that was then served as the rendition for good, and two requests
rendering the same file at once encoded into one path together.
It now writes beside the destination and renames into place. rename()
within a directory is atomic and replaces what is there, so the path is
either the previous rendition or a complete new one, and the loser of a
race leaves a whole image rather than a mixture of two. The temporary
file is removed on the way out either way.
The read side gets the other half: an empty file is not a rendition, so
both routes replace one rather than serve it. Writing through a temporary
file means this state can no longer be created here, but an installation
that ran an older version can already have it on disk, and nothing else
will ever clear it.
Three tests: an empty rendition is replaced on the signed-in route and on
the public one, and a successful render leaves nothing half-written
behind. Without the fix the first two go red; the third is about the fix's
own temporary file and passes either way.
FileThumbnailController::preview() writes at most one FilePreviewed row
per viewer per file per five minutes, because a browser turns one video
into a long tail of Range requests against the same URL. Its docblock
names the anonymous route as the place the same act happens without an
account -- and that route logs unconditionally.
Measured: five requests for the same public file, five
PublicFilePreviewed rows, against one for the signed-in twin. One visitor
watching one clip buries the public half of the activity log, which is
also the half an operator reads to see what the outside world is doing.
The window is now a shared PreviewLog, next to PreviewKind, which the two
preview routes already share for the same reason. Keying is unchanged for
a signed-in viewer; an anonymous one has no account to key on, so the
request IP stands in -- the same substitute the API's rate limiter makes
for an unauthenticated caller. It is a cache key with a five-minute life
and never reaches the log, which keeps its own decision about recording an
IP (ActivityLogger::shouldRecordIp, Setting::DownloadIpLogging).
Three tests: the replay is one row, two visitors are two rows, and the
window is per file. Without the fix the first goes red.
Two routes still assumed every file sits on local disk, which stopped
being true the moment external storage was switched on. A share link
answered with X-Accel-Redirect whatever the file's disk said, pointing
nginx at a path it has nothing behind; a public listing built a
thumbnail from Storage::disk('files')->path(), which for an externally
stored file is a path nobody ever wrote. Both fail only for installs
using S3, and only on those two routes, so the same file downloading
correctly from the file manager made the share link look like the
broken thing rather than where the file lives.
Neither is a new rule. FileDownloadController and
FileThumbnailController already did it right, which is the actual
finding: the knowledge was sitting in a private method on one class and
inline in another, so the next caller could not inherit it and did not.
Both are now objects with one job.
StoredFileResponse replaces InlineFileResponse and grows an
attachment() alongside inline(), since the two differ only by
disposition. LocalSourceFile takes a closure rather than returning a
path: the version that returned one also left the caller to unlink it,
and both of those are exactly the mistakes made here.
The regression tests fail against the previous controllers — checked in
both directions rather than assumed.
v1 could preview four kinds of file in a modal — images, video, audio and
PDF. v2 previewed only images, and not by decision: preview shipped as part
of the image *thumbnail* work (1c68aa1), so "previewable" quietly became a
synonym for "GD can decode it". FileThumbnailController::preview() gated on
ThumbnailGenerator::SUPPORTED_MIME_TYPES, the frontend mirrored the same
four types, and the dialog was a hardcoded <img>.
Rather than widen that list — it drives pathFor(), extensionFor(),
generate() and FileDiskCleanup, and a video reaching getimagesize() is a
500 — this separates the two questions. PreviewKind now answers "may these
bytes be served inline, and what element renders them?", while
ThumbnailGenerator keeps answering the narrower "can this app decode it
itself?", which is what renditions, the cache and the watermark hook
actually depend on. Image delegates to it so the two cannot drift.
The allowlist stays a security boundary: mime_type is sniffed from the
bytes, so text/html and image/svg+xml remain excluded, and PreviewKind is
deliberately narrower than "formats a browser might cope with" — no
quicktime, avi or matroska, because an embedded player for those shows a
black rectangle. Those still download exactly as before.
docs/security-audit-2026-08-05.md finding 1 recorded that adding
application/pdf "should be a conscious decision". This is that decision,
and three things were measured rather than assumed:
- An <iframe sandbox> cannot be used. Chrome refuses to run its PDF viewer
in a sandboxed frame at all (ERR_BLOCKED_BY_CLIENT, with or without
allow-same-origin) — the attribute removes the feature, it does not
harden it.
- nginx's `Content-Security-Policy: sandbox; default-src 'none'` on
/protected-files/ does work (a <video> frame lands in an opaque origin),
but Chrome exempts its PDF viewer from it, so it is not what protects
the PDF case.
- What does is the allowlist plus the browser's own PDF sandbox, where PDF
JavaScript has no DOM and no cookies.
Range requests were verified end to end: 206 with a correct Content-Range,
a byte-perfect file reassembled from three ranges, and a real browser
seeking to 10s of a 20s clip. nginx drops the upstream Content-Length on
the X-Accel path, so there is no collision.
Two settings, both defaulting on so no installation loses what it has:
clients_can_preview_files and public_listing_preview_enabled. Staff are
never gated. The anonymous side needed a route of its own — there was no
public preview endpoint — with its own throttle bucket, since a bare
throttle: shares one counter across that whole block.
A preview now logs at most one FilePreviewed per viewer per file per five
minutes: a <video> turns one deliberate act into a long tail of Range
requests, and a row each would bury the log.
Also fixes a layout bug the tests could never catch. A portal file row was
flex justify-between with three children — name, comment trigger, download
— so the middle one settled wherever the name happened to end and the
comment icon sat at a different place on every row. The name block now
takes the slack and every action lives in one trailing group, with the
comment trigger in a fixed-width slot so the icons form a column. And
because half the previewable files have no thumbnail to click — a PDF, an
mp3 and an mp4 all render as a generic icon — every row gains an explicit
PreviewAction beside DownloadAction, matching whatever style that theme
gives its download control.
Client file sharing, rebuilt from the ground up: a private area per
client, resumable uploads, folders, groups and categories, sharing with
expiry dates and download limits, comments, file versions, an activity
log, a REST API, and sixteen languages.
This repository begins here. ProjectSend 2 was developed privately, and
that development history is not published — the previous generation
remains available, with its own history, at projectsend/legacy.
Free software under the GNU General Public License v2, or (at your
option) any later version.
ignacionelson