Create DSL for RouterFunction and RouterFunctions [SPR-16953]

[spring-projects-issues]

Arjen Poutsma opened SPR-16953 and commented

We should add a (Java) DSL to org.springframework.web.servlet.function that makes it easier to discover the routing possibilities that all the request predicates offer.

So, instead of writing

RouterFunction routerFunction = route(GET("/pets/{id}", request -> ServerResponse.ok.build())

where both route and GET are statically imported, it should be more discoverable.

For instance, by introducing a builder with methods that directly express common request predicates, eg. routeGET(String, HandlerFunction) instead of route(RequestPredicate, HandlerFunction.

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Issue Links:

• Introduce Servlet version HandlerFunction and RouterFunction [SPR-16952] #21490 Introduce Servlet version HandlerFunction and RouterFunction
• Improve RouterFunctions reference documentation [SPR-17016] #21554 Improve RouterFunctions reference documentation

Referenced from: commits 91e96d8, 8202052

[spring-projects-issues]

Adam Berlin commented

I think an improvement might be an instance of a class that includes GET, POST, etc, so that you end up with

route.get("/pets/{id}", request -> ServerResponse.ok.build())

This way, I can discover my options by looking at the route object. When the methods are static methods, it is too easy to pluck them off of their class, and therefore harder to remember where they come from and discover more alternatives.

[spring-projects-issues]

Arjen Poutsma commented

This is now complete, see this commit: 8202052

The test case shows sample usage scenarios: https://github.com/spring-projects/spring-framework/blob/master/spring-webflux/src/test/java/org/springframework/web/reactive/function/server/RouterFunctionBuilderTests.java

[spring-projects-issues]

Arjen Poutsma commented

Reopened after feedback received during Spring meeting.

[spring-projects-issues]

Arjen Poutsma commented

Significantly changed the usage of the route builder, based on feedback received during team meeting. See 91e96d8