Pydantic's AnyHttpUrl automatically appends a trailing slash to bare
hostnames (e.g., http://localhost:8000 becomes http://localhost:8000/).
This causes OAuth discovery to fail in clients that validate per
RFC 8414 §3.3 and RFC 9728 §3, which require the returned issuer/resource
URL to be identical to the URL used for discovery.
Add field_serializer to OAuthMetadata.issuer,
ProtectedResourceMetadata.resource, and
ProtectedResourceMetadata.authorization_servers to strip the trailing
slash during JSON serialization.
Fixes#1919Fixes#1265
Reported-by: joar
Github-Issue: #1919
Max Isbey
96c7a43187