markdown/deck/html_fragment rendered author-influenced content verbatim,
so <script>/<img onerror>/etc. executed on the Daybook origin — self-XSS
against the owner's session, and (post-sharing) unauthenticated via /s/.
Two layers, both in artifacts/views.py:
- Create-time allowlist sanitization via nh3 (maintained ammonia/Rust
sanitizer, not deprecated bleach). Keeps formatting/tables/links/images
(incl. relative /assets URLs) and codehilite markup; drops script, on*
handlers, style, unknown tags, and javascript:/data: URLs. html_full is
deliberately NOT sanitized (documented verbatim escape hatch).
- Serve-time CSP (script-src 'none') for the sanitized kinds, on both
/a/{id} and the unauthenticated /s/{token} route. Being a response
header, it also neutralizes scripts in artifacts stored before this fix.
Not applied to html_full or json/csv (json/csv data is already escaped;
their viewers need their own JS).
Verified live across all kinds; 7 regression tests added. 102 tests pass.
Not addressed (noted in the issue): CSV formula injection,
CSRF_COOKIE_HTTPONLY (moot with XSS closed), nonce CSP for json/csv/full.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Uploading a .xlsx file no longer becomes a generic downloadable binary -
it's read server-side with openpyxl and converted to a csv artifact,
rendering in the same interactive grid as a native CSV post. Detected by
content type or .xlsx extension (some clients send generic/incorrect
content types for multipart uploads). Only the active sheet converts;
formula cells use whatever cached result the spreadsheet software last
saved (openpyxl doesn't evaluate formulas itself). Corrupt/unreadable
files return 400.
Since the existing posting script already forwards any non-text file via
multipart with no special-casing, `daybook_post.py balance_sheet.xlsx`
already works with zero script changes - verified live.
Two real bugs found and fixed while building this, both now covered by
regression tests:
- {**a_querydict, ...} silently wrapped every value (including title) in
a list - Python's ** spread on a dict subclass bypasses QueryDict's
__getitem__ override and exposes its internal one-list-per-key storage
directly. Fixed by building the delegated dict explicitly via .get().
- Pre-setting None for absent optional fields (e.g. source_prompt) defeated
create_text_artifact's own data.get(field, default) calls, since .get()
only falls through to its default when the key is *missing*, not when
the value is None - caused a NOT NULL constraint failure. Fixed by only
setting keys that were actually provided.
- csv.writer's default "\r\n" terminator was getting doubled by
Path.write_text()'s own newline translation on Windows, producing a
blank line between every row. Fixed with lineterminator="\n".
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Enables codehilite on the markdown renderer (Pygments, 'friendly' style,
vendored as static/themes/pygments.css) so fenced code blocks get real
syntax highlighting with zero client-side JS - matching the "themes are
CSS-only" stance in framework_artifact_rendering.md. Verified live against
the running dev instance: a fenced python block renders with highlighted
keyword/string/function spans.
This was Gap 2 from planning/2026-09-02-artifact_kind_gaps_for_frequent_agent_output.md,
picked as the first fix since it needed no new kind or design decision -
just enabling an existing markdown extension.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Daybook: a self-hosted, multi-user Django + DRF app where agents, scripts,
or people publish artifacts and each logged-in user browses their own
time-ordered, label-filterable feed.
This squashes prior local development history (kept privately on a separate
branch) into a single clean starting point for the public repository.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
