Replace a separate call to subprocess, starting `node` from scratch,
with an optional standalone node Express service which performs the
rendering. In benchmarking, this reduces the overhead of a KaTeX call
from 120ms to 2.8ms. This is notable because enough calls to KaTeX in
a single message would previously time out the whole message
rendering.
The service is optional because he majority of deployments do not use
enough LaTeX to merit the additional memory usage (60Mb).
Fixes: #17425.
If the script comes from a different origin than the requesting page,
and is not marked `crossorigin="anonymous"`, the `window.onerror`
handler receives no information other than "Script error." in the
event of a runtime error.
This effectively silences blueslip errors in development if the user
is developing on a remote host (such as a DigitalOcean droplet), since
static resources are served from `hostname.zulipdev.org`, and the
realm is served from `realmname.hostname.zulipdev.org`. It also
silenced blueslip reporting in production for any non-default (non-"")
realms. Sentry reporting, Vagrant developments, and truly ancient or
insecure browsers were unaffected.
Add the necessary `crossorigin="anonymous"` attribute to the
`<script>` tag to allow blueslip access to this error information.
webpack-dev-server 4.12.0 introduced a global handler that shows a
full-screen overlay for all runtime errors, but it’s redundant with
our blueslip_stacktrace handler and less functional at this time.
Signed-off-by: Anders Kaseorg <anders@zulip.com>
Anders Kaseorg
Sayam Samal
Alex Vandiver