Reported case (Foxxify): Tidal returned error 1002 ("Invalid redirect
URI") on every authentication attempt for users accessing SoulSync
from a network IP. User had ``http://127.0.0.1:8889/tidal/callback``
registered in his Tidal Developer Portal — matching the SoulSync UI
default and docs.
Root cause: the /auth/tidal route at web_server.py:5594-5598 had a
"fallback: dynamically set based on request host" branch that fired
when ``tidal.redirect_uri`` config was empty AND the request didn't
come from localhost. That fallback overrode the TidalClient
constructor's safe default (``http://127.0.0.1:<port>/tidal/callback``)
with a uri built from request.host like
``http://192.168.x.x:8889/tidal/callback``. Tidal compares strings
exactly so this never matched the documented portal registration and
the user got 1002 before the consent screen even rendered.
The trap is the SoulSync settings UI displays the default URI as the
placeholder + "Current Redirect URI" display — but the placeholder
never gets saved to config unless the user explicitly clicks Save.
Most users who follow the docs (register the displayed default with
Tidal, then click Authenticate) hit the empty-config path and the
broken fallback.
Fix: drop the request-host fallback. Empty config falls back to the
constructor default that matches the documented portal registration.
The existing post-auth swap-step in the instructions page below
handles the Docker / remote-access case as designed:
1. SoulSync sends 127.0.0.1:8889 in the authorize URL → matches
portal → Tidal accepts.
2. User authorizes → Tidal redirects browser to 127.0.0.1:8889
(which fails locally — nothing on user's machine listens there).
3. Instructions tell user to swap 127.0.0.1 with the host they're
accessing SoulSync from.
4. Swapped URL hits the container's exposed callback port → auth
completes.
8 regression tests in tests/test_tidal_auth_redirect_uri.py:
- Configured redirect_uri sent verbatim (localhost / custom port /
explicit network IP)
- Empty config falls back to constructor default — NOT request.host
(the actual reported scenario, with explicit assertion message
warning if the bug returns)
- Empty config + localhost access uses the same default (sanity)
Full pytest 1635 passed; ruff clean.
Broque Thomas