# spring-security-demo

Companion code for the Spring Security series on [ankurm.com](https://ankurm.com). Each
directory is a self-contained Maven project for one article, with its own `pom.xml`, its own
numbered documentation chapters, and its own captured output under `docs/output/` — regenerated
by that module's `scripts/run-all.sh`, never typed by hand.

| Module | Article | What it demonstrates |
|---|---|---|
| [`context-propagation/`](context-propagation/README.md) | [Spring Security Context Propagation: The Complete Guide](https://ankurm.com/spring-security-context-propagation-complete-guide/) | Whether a `SecurityContext` survives `@Async`, executors, virtual threads, `StructuredTaskScope`, Reactor, schedulers and the servlet filter chain |
| [`method-security/`](method-security/README.md) | [Method Security in Spring Security 7: `@PreAuthorize`, `@PostAuthorize` and the Proxy Traps](https://ankurm.com/spring-security-7-method-security-proxy-traps/) | What the method-security annotations do, the full SpEL surface, and the cases where the check silently does not run |
| [`filter-chain/`](filter-chain/README.md) | [The Spring Security Filter Chain Explained](https://ankurm.com/spring-security-filter-chain-explained/) | Every filter in the default chain and its order number, where a custom filter actually lands, and how to read the TRACE log |

The three are related more closely than they look. `filter-chain` is about how an
`Authentication` gets into `SecurityContextHolder` in the first place and in what order;
`context-propagation` is about whether it survives leaving the request thread; `method-security`
reads it back on whatever thread it ends up on. An `@Async` method carrying `@PreAuthorize` fails
with `AuthenticationCredentialsNotFoundException` for reasons that belong to the second module,
not the third — and a custom authentication filter that never populated the context in the first
place fails the same way, for reasons that belong to the first.

## Common ground

All three modules target the same verified stack: **JDK 25** (Temurin 25.0.4.1+1),
**Spring Framework 7.0.9**, **Spring Security 7.1.1** — the versions Spring Boot **4.1.1**
manages. Versions were taken from `maven-metadata.xml` on Maven Central rather than from
release announcements.

`context-propagation` additionally needs `--enable-preview`, because `StructuredTaskScope` is
still a preview API on JDK 25. `method-security` does not. `filter-chain` is the only module
that is a real servlet application: it inherits `spring-boot-starter-parent` and runs on Tomcat,
because the thing it demonstrates only exists inside a servlet container.

## Running a module

```bash
cd method-security          # or context-propagation, or filter-chain
./scripts/run-all.sh        # every demo plus the test suite, regenerating docs/output/
mvn test                    # just the assertions
```

`filter-chain` also has `./scripts/run.sh <profile>` and `./scripts/stop.sh`, because its
scenarios are a running web application rather than a `main()` method.

## License

MIT — see [LICENSE](LICENSE).