vienalatina/apps/board/render.py
Claude 6ac814475e
Add a members area: roles and an internal board
Everything on this site so far has been a file built from git. This is the
first component that runs code to answer a request and the first whose data
git does not hold, so the trade is stated in the README and the backup script
is not optional.

Roles are owner, admin and user. The owner is seeded once from BOARD_OWNER and
cannot be seeded again, because otherwise editing a compose file would be a
quieter way to take the top role than asking for it; ownership moves only by
transfer, inside the app. There is exactly one owner and a partial unique index
enforces it, so the invariant holds even when a handler is wrong. The owner is
beyond suspension and demotion by everyone, themselves included. Only the owner
makes admins; admins make users.

Sign-in goes through Gitea as a confidential OAuth client — the opposite of
Decap, which has to be public because it runs in the browser. The rule the
whole thing rests on is that a Gitea account is not a membership: entry needs
an active row in `members`, or every account on the instance is a member,
starting with the translations bot.

Admins can delete any post; nobody can edit anyone else's, admins included.
Taking a post down is visible to its author. Quietly rewriting it is not, and
an admin who could do that could leave a sentence attributed to someone who
never wrote it. The plan said admins could do both; this is the one place the
implementation departs from it.

Markdown renders with raw HTML disabled, which is the entire XSS defence and
the reason there is no sanitiser: the renderer emits only its own tags and
escapes the rest. The CSP carries no 'unsafe-inline', which makes an inline
onsubmit silently inert rather than broken, so the confirmation dialogs live in
a static file and a test fails any template that grows an inline handler.

GDPR is in scope rather than deferred: erasure removes the member row and moves
their authorship to a tombstone so the conversations around them still read,
and any member can download their own writing.

Verified: 63 checks pass, covering the membership gate, every role predicate, a
direct insert of a second owner being refused by the index, atomic ownership
transfer, CSRF, an offsite login redirect, script tags rendering as text, soft
deletes leaving both listings and exports, and the member screens rendering for
each role. Smoke-tested live: headers, both static assets, and the bare
/comunidad redirect that the Caddy matcher has to cover.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NizVpJ2dwzCbjCrTLCjeHn
2026-09-22 10:57:18 +00:00

41 lines
1.4 KiB
Python

"""Turning what members type into HTML.
`html=False` is the whole security model, and it is worth understanding rather
than copying. With raw HTML disabled, markdown-it never passes a fragment of
the input through untouched: it emits only the tags its own rules produce, and
everything else is escaped as text. A `<script>` in a post comes out as visible
characters, not as a tag.
That is why there is no sanitiser here. A sanitiser is what you need when you
have decided to allow *some* HTML and must then decide which — a judgement with
a long history of near misses. Allowing none is a smaller thing to get right.
Anyone tempted to set `html=True` later to embed a video: that single flag
turns this file into an XSS hole, and re-enabling it means adding a sanitiser
and owning its allowlist forever.
"""
from __future__ import annotations
from markdown_it import MarkdownIt
from markupsafe import Markup
_md = (
MarkdownIt("commonmark", {"html": False, "linkify": True, "breaks": True})
.enable("linkify")
.enable("table")
.enable("strikethrough")
)
def to_html(text: str) -> Markup:
return Markup(_md.render(text or ""))
def excerpt(text: str, limit: int = 220) -> str:
"""A plain-text preview for the thread list — no markup, no truncated tags."""
flat = " ".join((text or "").split())
if len(flat) <= limit:
return flat
return flat[:limit].rsplit(" ", 1)[0] + " …"