`BASE_PATH=/mail` mounts the whole app under a prefix, for a host that is not
ihasmail's alone. Unset -- every deployment that exists -- is the domain root
and is byte-for-byte what it was: the canonical form of the setting is the
empty string, and `""` concatenated onto `/api/health` is `/api/health`.
That choice of canonical form is the whole design. A trailing slash would have
been the obvious alternative, and it fails quietly in exactly one place: at the
root it makes `//api/health`, which is not a path on this host but a
protocol-relative URL to a host called `api`. One call site forgetting to
branch is a request leaving the origin. So the empty string, one leading slash,
no trailing one, worked out once in `scripts/basePath.mjs` -- plain JS, next to
`version.mjs`, because the web build and the server both have to reach the same
answer and two implementations of "what does /mail/ mean" is precisely the bug
where the server serves an app whose script tags point somewhere else.
`/mail`, `mail`, `/mail/` and `//mail//` all mean the same mount; a deployment
should not fail over a trailing slash.
Unlike everything else ihasmail is told, this one cannot wait for the process
to start. The bundle writes its own asset URLs into index.html, so `BASE_PATH`
is read at build time for Vite's `base` as well as at run time for the routes,
and the Dockerfile carries one value into both. Get them out of step and the
page comes up blank with a 404 in a console nobody has open -- so the static
handler, which is reading index.html anyway, checks what it asks for and says
so in the log once per build.
Everything moves together. The API mounts at `${base}/api`; the router is
given the base once, so every `<Route path>` and `<Link href>` stays written
root-absolute and wouter does the rest; `apiFetch` adds the prefix in one place
rather than at forty call sites; the session cookie's Path narrows to the mount
so two instances on one host cannot sign each other out.
Two things need no prefix at all, and it is worth saying why they were not
given one. A manifest's members resolve against the manifest's own address, so
relative URLs there follow the mount with nothing substituted at build time --
which is also why `public/` needed no template step. The service worker is the
same trick: it is served from the mount, so `new URL("./", self.location)`
tells it where that is, and a worker that derives the value cannot disagree
with the page that registered it.
Anything outside the mount is a 404 rather than the app shell, and
`stripBasePath` does not use `startsWith` -- under `/mail` this process shares
a hostname, and answering `/mailbox` with our index would shadow a neighbour
instead of letting it 404 honestly. For the same reason the notification-click
handler now checks the path as well as the origin: `includeUncontrolled` widens
`matchAll` to the whole origin, which off the root would have navigated a
stranger's tab to our inbox.
Inline images in a draft were the one silent trap. They are matched by their
blob URL on the way out, once unanchored and once anchored, and a bare
`/api/blob/` still appears inside `/mail/api/blob/...` -- so one pattern would
have replaced the tail and left `/mail` in front of a `cid:`, and the other
would have missed and sent the message linking to the sender's own webmail.
Both patterns are built from the base now.
A shadow root scopes selectors, not layout. `position:fixed` in mail CSS is
still positioned against the viewport, and the containment meant to stop that
sat inside the shadow root as `.ihm-email-root { contain: content }` — in the
same tree as the message's own <style>, which is inserted after it and simply
overrides it. Any sender could cover the entire window with markup of their
choosing, inside our own origin: a ready-made place to ask for a password.
Verified in a browser: the message rendered at exactly the viewport size with
the maximum z-index.
Moving the containment onto the shadow host does not fix it — mail CSS reaches
the host through `:host`, and an `!important` there beats an `!important` from
the app's own stylesheet, because importance reverses tree order in the
cascade. An ancestor of the host is the one thing mail CSS has no selector
for, so the control goes on .message-body. `layout` rather than `paint`: it
makes the element a containing block for fixed descendants without clipping
tall messages.
The sanitizer now also turns fixed and sticky positioning static and defangs
`:host`, as a second line that does not depend on one CSS declaration.
Checked end to end against the real stylesheet afterwards: the same message
renders 1678x112 instead of 1720x1279.
Messages render on a white card in every theme. That is deliberate for mail
that styles itself, but #4 points out the case it gets wrong: a message with
no styling of its own has nothing worth preserving, and flashing white at
someone reading in the dark is a real cost.
Appearance gains a switch under the theme cards, off by default so the
current behaviour is unchanged. With it on, HTML mail that declares no
colours follows the app theme; mail that sets a background or text colour
still gets the light card it was designed for, because half-darkening someone
else's design is worse than leaving it alone. Plain-text mail already
followed the theme and is untouched by the switch.
The themed palette is expressed in the app's own custom properties, which
cross the shadow boundary, so switching theme repaints open messages without
re-rendering them, and the accent-coloured link stays consistent. The host
element takes color-scheme: inherit so form controls and scrollbars inside a
message match too.
htmlDeclaresColors covers bgcolor attributes, <font color>, and colour or
background declarations in style attributes and <style> blocks, while
ignoring near-misses like border-color and ?color= in a URL.
Closes#4
jcoffey-dev