Handler Interceptor Adapter in Spring WebFlux [SPR-17264]

[spring-projects-issues]

jakubdyszkiewicz opened SPR-17264 and commented

My team is in the middle of migrating our Spring MVC extensions to WebFlux.

We've got a feature that lets our clients customize metric of controller method. To do that we've created our annotation that is processed by HandlerInterceptorAdapter.

What's more, our metrics convention is a controller method name, not a path.

The problem is that I can't see any equivalent of this in Spring WebFlux. I can't use WebFilter because Spring does not know yet which endpoint will be called, therefore I can't process annotation. How can I implement that?

The closest workaround I found is to use RequestMappingHandlerMapping and somehow build a map of Map<String(path), HandlerMethod>, but this is cumbersome in my opinion

Thanks

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Issue Links:

• Set BEST_MATCHING_HANDLER_ATTRIBUTE in WebFlux.fn [SPR-17367] #21900 Set BEST_MATCHING_HANDLER_ATTRIBUTE in WebFlux.fn

0 votes, 5 watchers

[spring-projects-issues]

jakubdyszkiewicz commented

Hello, any updates on this? It essentially blocks usage of WebFlux for us. We cannot deploy applications without controllers metrics.

[spring-projects-issues]

Rossen Stoyanchev commented

Indeed there is no equivalent in WebFlux. The selected handler (i.e. controller method) is saved in a request attribute under the name HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE. You could check that in a WebFilter after request handling:

WebFilter webFilter = (exchange, chain) -> {
	return chain.filter(exchange)
			.doOnSuccess(aVoid ->{
				// ...
			});
};

An @ModelAttribute method on an @ControllerAdvice class could also used to intercept.

[spring-projects-issues]

Kevin Binswanger commented

Rossen Stoyanchev It seems like HandlerMapping.BEST_MATCHING_HANDLER_ATTRIBUTE is only set for requests that are routed via @RequestMapping and not things routed by RouterFunctions. Is that accurate, and is there a workaround for RouterFunctions?

 

RouterFunctionMapping vs RequestMappingInfoHandlerMapping and AbstractUrlHandlerMapping.

[spring-projects-issues]

Rossen Stoyanchev commented

Arjen Poutsma, any reason we couldn't set the BEST_MATCHING_HANDLER_ATTRIBUTE to the selected HandlerFunction?

[spring-projects-issues]

Brian Clozel commented

Rossen Stoyanchev, it's supported as of Spring Framework 5.1 with RouterFunctions.MATCHING_PATTERN_ATTRIBUTE, see #21635

[spring-projects-issues]

Arjen Poutsma commented

Rossen Stoyanchev No reason, except that no-one has asked for it before. I've created #21900 to track this change.

Brian Clozel Rossen is asking about the best matching handler, not best matching pattern.