Create reactive HiddenHttpMethodFilter to support alternate mappings [SPR-15206]

[spring-issuemaster]

Greg Turnquist opened SPR-15206 and commented

Thymeleaf allows

<form th:method="delete" th:action="@{'/foo'}">
     <input type="submit" value="Delete" />
</form>

in order to embed a hidden "DELETE" verb, which turns an HTML POST into an HTTP DELETE (same for PUT and other HTTP verbs).

We need support for this in Spring WebFlux.

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Affects: 5.0 M4

Referenced from: commits 5488906, e4be713

[spring-issuemaster]

Greg Turnquist commented

@bclozel Care to review my PR? => #1319

[spring-issuemaster]

Brian Clozel commented

Thanks!