WebFlux commitActions are called after status, headers and cookies are set [SPR-16597]

[spring-issuemaster]

Nicolas Portmann opened SPR-16597 and commented

ServerHttpResponse allows commitActions to be added (e.g. inside a WebFilter) via the beforeCommit method.

AbstractHttpServerResponse however calls the protected methods applyStatusCode(), applyHeaders() and applyCookies() synchronously before the Mono<Void>s passed as commitActions get executed. This makes it impossible to change the status code, add headers or cookies in beforeCommit actions asynchonously. A use case for this would be to add values from the subscriber context to the response headers.

AbstractHttpServerResponse#doCommit should wrap the calls to the applyXXX() methods in a mono which is subscribed to after the other commitActions.

Current code:

this.commitAction.add(() -> {
    applyStatusCode();
    applyHeaders();
    applyCookies();
    // ...
    return Mono.empty();
});

Proposed solution:

this.commitActions.add(() -> {
    Mono.fromRunnable(() -> {
        applyStatusCode();
        applyHeaders();
        applyCookies();
        // ...
    });
});

---

Affects: 5.0.4

Issue Links:

• #21882 Send static file action is invoked before applying the relevant headers

Referenced from: commits 72bbb26

[spring-issuemaster]

Nicolas Portmann commented

It looks as if this behavioral change was introduced in 9f8e845

[spring-issuemaster]

Rossen Stoyanchev commented

Well spotted, thanks!