java - Spring - Path variable truncate after dot - annotation

Question

I am trying to set up a REST endpoint that allows querying a user by their email address. The email address is the last portion of the path so Spring is treating [email protected] as the value foo@example and truncating the extension .com.

I found a similar question here Spring MVC @PathVariable with dot (.) is getting truncated However, I have an annotation based configuration using AbstractAnnotationConfigDispatcherServletInitializer and WebMvcConfigurerAdapter. Since I have no xml configuration, this solution will not work for me:

<bean class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping">
    <property name="useDefaultSuffixPattern" value="false" />
</bean>

I have also tried this solution which uses regex but it has not worked either.

@RequestMapping(value = "user/by-email/{email:.+}")

Does anyone know how to turn off the suffix pattern truncation without xml?

Answer 1

The dot in the path variable at the end of the URI causes two unexpected behaviours (unexpected for the majority of users, except those familiar with the huge number of Spring configuration properties).

The first (which can be fixed using the {email:.+} regex) is that the default Spring configuration matches all path extensions. So setting up a mapping for /api/{file} will mean that Spring maps a call to /api/myfile.html to the String argument myfile. This is useful when you want /api/myfile.html, /api/myfile.md, /api/myfile.txt and others to all point to the same resource. However, we can turn this behaviour off globally, without having to resort to a regex hack on every endpoint.

The second problem is related to the first and correctly fixed by @masstroy. When /api/myfile.* points to the myfile resource, Spring assumes the path extension (.html, .txt, etc.) indicates that the resource should be returned with a specific format. This behaviour can also be very useful in some situations. But often, it will mean that the object returned by a method mapping cannot be converted into this format, and Spring will throw a HttpMediaTypeNotAcceptableException.

We can turn both off with the following (assuming Spring Boot):

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

  @Override
  public void configurePathMatch(PathMatchConfigurer configurer) {
    // turn off all suffix pattern matching
    configurer.setUseSuffixPatternMatch(false);
    // OR
    // turn on suffix pattern matching ONLY for suffixes
    // you explicitly register using
    // configureContentNegotiation(...)
    configurer.setUseRegisteredSuffixPatternMatch(true);
  }

  @Override
  public void configureContentNegotiation(ContentNegotiationConfigurer configurer) {
    configurer.favorPathExtension(false);
  }
}

More about Content Negotiation.