ControllerLinkBuilderFactory should resolve placeholders

[51f0x]

The ControllerLinkBuilderFactory does not resolve placeholders in RequestMapping annotations.

Ex. @RequestMapping(value = "${myPath}/users")

The handling should be the same as in the RequestMappingHandlerMapping.

Stacktrace:

java.lang.IllegalArgumentException: Map has no value for 'myPath'
at org.springframework.web.util.UriComponents$MapTemplateVariables.getValue(UriComponents.java:277) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponents.expandUriComponent(UriComponents.java:221) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents$FullPathComponent.expand(HierarchicalUriComponents.java:642) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents.expandInternal(HierarchicalUriComponents.java:311) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents.expandInternal(HierarchicalUriComponents.java:46) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponents.expand(UriComponents.java:152) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponentsBuilder.buildAndExpand(UriComponentsBuilder.java:288) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.hateoas.mvc.ControllerLinkBuilderFactory.linkTo(ControllerLinkBuilderFactory.java:145) ~[spring-hateoas-0.15.0.RELEASE.jar:na]
at org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo(ControllerLinkBuilder.java:135) ~[spring-hateoas-0.15.0.RELEASE.jar:na]

[dschulten]

Normally, when linking to methods with request mappings having path variables, the variable value should be defined by some method argument. You pass it in after methodOn() when you 'call' the target method.

Could you please post how you use linkTo(methodOn())?

Btw. the notation with $ is not what I'm used to. Did you mean "/{myPath}/users"?

Dietrich Schulten
Escalon System-Entwicklung
D-74199 Donnbronn

---- Matthias schrieb ----

The ControllerLinkBuilderFactory does not resolve placeholders in RequestMapping annotations.

Ex. @RequestMapping(value = "${myPath}/users")

The handling should be the same as in the RequestMappingHandlerMapping.

Stacktrace:

java.lang.IllegalArgumentException: Map has no value for 'myPath'
at org.springframework.web.util.UriComponents$MapTemplateVariables.getValue(UriComponents.java:277) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponents.expandUriComponent(UriComponents.java:221) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents$FullPathComponent.expand(HierarchicalUriComponents.java:642) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents.expandInternal(HierarchicalUriComponents.java:311) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.HierarchicalUriComponents.expandInternal(HierarchicalUriComponents.java:46) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponents.expand(UriComponents.java:152) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.web.util.UriComponentsBuilder.buildAndExpand(UriComponentsBuilder.java:288) ~[spring-web-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.hateoas.mvc.ControllerLinkBuilderFactory.linkTo(ControllerLinkBuilderFactory.java:145) ~[spring-hateoas-0.15.0.RELEASE.jar:na]
at org.springframework.hateoas.mvc.ControllerLinkBuilder.linkTo(ControllerLinkBuilder.java:135) ~[spring-hateoas-0.15.0.RELEASE.jar:na]

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[51f0x]

Spring MVC does resolve the @RequestMapping(value = "${myPath}/users") to a mapping like "/somePath/users" if the PropertyPlaceholderConfigurer resolves ${myPath} to "somePath". ${myPath} is therefor replaced when starting the application. All arguements like you mention {xxx} (PathVariables) must be given in the request.
I would like to have the same behaviour in the ControllerLinkBuilderFactory as in the RequestMappingHandlerMapping of Spring MVC.

I'm using the ControllerLinkBuilder like: linkTo(methodOn(RestUsersController.class).getAllUsers()).withSelfRel())

[sp00m]

A solution could be to make AnnotationMappingDiscoverer.getMapping(Class<?>, Method) call applicationContext.getBeanFactory().resolveEmbeddedValue(...) (or use an EmbeddedValueResolverAware instance) before returning the discovered mapping, what do you think about it?

[51f0x]

Sure, this would be a good solution.

[sp00m]

I haven't been able to implement the fix in spring-hateoas directly, since AnnotationMappingDiscoverer isn't a Spring managed bean, and I can't find a way to access an EmbeddedValueResolverAware instance then... I hope someone who masters Spring better than me will be able to handle it ;)

I implemented a temporary fix in my projects by extending ControllerLinkBuilderFactory, see LinkBuilder and LinkBuilderFactory.

[gregturn]

Resolved via #361.