feat(desktop): Slack-style in-app preview for generic file attachments - #23
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Clicking a FileCard now opens an in-app preview dialog (name, type, size, Close, Download) instead of immediately invoking the native save dialog. Markdown uses the existing sanitized chat renderer; HTML is inert source only and is never given to webview navigation or an iframe. Other text types get a scrollable preview; binaries keep chrome plus a no-preview state. Bytes still load through fetch_media_bytes / download_file. Signed-off-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: jmfcamp <jmfcamp@users.noreply.github.com>
…e row Forum post cards wrap Markdown in a row button. The FileCard click was bubbling, navigating away, and unmounting the preview before it opened. Signed-off-by: Cursor Agent <cursoragent@cursor.com> Co-authored-by: jmfcamp <jmfcamp@users.noreply.github.com>
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marked this pull request as ready for review
August 20, 2026 23:23
This was referenced Aug 20, 2026
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Summary
Generic file attachments (
.md,.html, PDF, zip, …) used to open the native save dialog on FileCard click. This change matches Slack-style behavior: click opens an in-app preview window; Download stays available from that window.Images and video are unchanged (lightbox / player). Relay
serve_inlineand MIME deny lists are unchanged — HTML stays an inert download on the wire (block/buzz#5569).Preview routing:
.md/text/markdown) — existing sanitized chat markdown pipeline (interactive={false}).html/.htm/text/html) — inert syntax-highlighted source only. No<iframe>, nosrcdoc, no webview navigation to/media/(stored-XSS)text/plain, CSV, JSON, sniffed UTF-8 octet-stream) — scrollable previewfetch_media_bytes/download_file, never<a href>FileCard clicks
stopPropagation()so a preview opened from a forum post card (or any other clickable row) is not immediately unmounted by the row’s own click handler.Hula Buzz branding (
productName,com.huladesk.buzz,hulabuzz://) is untouched.Related issue
None found in this fork. Closest official context: block/buzz#5569 (HTML accepted as inert download).
Testing
desktop/src/shared/ui/filePreview.test.mjs— md/html/text/binary routing, size cap, UTF-8 sniff, and “HTML is never a webview navigation / unsandboxed iframe”resolveFileCardnow forwards imeta MIME for preview routingtsc --noEmitpassedfile-attachment.spec.ts:download_file; Escape dismissesstopPropagationfix)<script>does not run in the app webview