Three modules on Spring Boot 4.1.1 with Spring Authorization Server 7.1.1: the provider
itself, a relying party, and an API that trusts its tokens. Client registration, PKCE,
a custom consent page and token customisation, with profiles that make each failure
reproducible.
Every claim is backed by captured output in docs/output/as-*.txt, regenerated by
authorization-server/scripts/run-all.sh. Notable findings, verified against the jars:
- OAuth2AuthorizationServerConfiguration.applyDefaultSecurity(HttpSecurity) was deleted
in 7.0, and both configuration classes moved into spring-security-config
- ClientSettings.requireProofKey flipped from false to true, on the authorization server
(1.5.8 -> 7.1.1) and on the OAuth2 client (6.5.1 -> 7.1.1)
- requireProofKey(false) does not make PKCE optional for a public client; the code
verifier is that client's only authentication at the token endpoint
- MediaTypeRequestMatcher(TEXT_HTML) matches Accept: */*, so the token endpoint answers
API callers with 302 -> /login unless setIgnoredMediaTypes(ALL) is called
Also renames the repository to spring-auth-demo and cross-links the new chapter set from
the existing documentation.
Companion code for the follow-up article. The repository now holds two Maven
projects sharing one docs/ tree:
jwt-authentication/ the hand-written filter application (unchanged, moved)
oauth2-resource-server/ a resource server, a Keycloak compose, and a stub
issuer whose JWK Set can be mutated on command
The stub exists because Keycloak will not rotate a signing key at a chosen
second, report how many times its JWKS endpoint was fetched, or drop a key from
the published set on request - and the caching and rotation measurements need
all three. The Keycloak run confirms the same code path against a real issuer.
Findings captured under docs/output/, all from real runs:
* The default validator stack does not check aud. A token minted for another
service in the same realm is accepted.
* Spring Security builds its JWKSource with refreshAheadCache(false) and
rateLimited(false), overriding two of Nimbus's protective defaults, and
enables Nimbus caching only when NO Spring cache was supplied - so
supplying one removes the five-minute expiry.
* A key retired from the JWK Set stops being accepted at t+300s with the
default cache, and never with a Spring cache that has no TTL.
* 25 tokens carrying an unknown kid produce 25 JWKS fetches at the issuer,
through permitAll() endpoints included.
* A hyphenated client id in an authorities-claim-expression parses as
subtraction; the SpelEvaluationException is swallowed and logged at TRACE.
* A clientScopes key in a Keycloak realm import replaces the built-in scopes
rather than adding to them.
New docs chapters 12-18. README covers both projects. Existing docs and scripts
updated for the new paths; no docs/output/ file from the first article moved, so
links in the published article still resolve.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013f7f2XZXrQ6gW3RtZE187t
