Support WebJars directly in Jersey

[jessemillar]

This is half question and half (potential) bug report. I've inquired about the problem in the webjars-locator project and was directed here.

I'm trying to get swagger-ui working in a version agnostic manner inside of Spring Boot with Jersey and Tomcat. According to the WebJars documentation, having a pom.xml similar to the following should allow me to access swagger-ui via http://localhost:8080/webjars/swagger-ui/ but it only works via http://localhost:8080/webjars/swagger-ui/3.6.1.

<dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-jersey</artifactId>
    </dependency>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-tomcat</artifactId>
    </dependency>
    <dependency>
      <groupId>org.webjars</groupId>
      <artifactId>swagger-ui</artifactId>
      <version>3.6.1</version>
    </dependency>
    <dependency>
      <groupId>org.webjars</groupId>
      <artifactId>webjars-locator</artifactId>
      <version>0.32-1</version>
    </dependency>
</dependencies>

Is there anything special I'd need to do to get webjars-locator working in this situation? It works just fine in spring-boot-starter-web which leads me to believe this is potentially a bug.

[philwebb]

Spring MVC support is provided via org.springframework.web.servlet.resource.WebJarsResourceResolver from the Spring Framework and Spring Boot gets it for free.

We currently don't have the same type of support for Jersey.

[marti1125]

@jessemillar @philwebb could I contribute with this?

[jessemillar]

@marti1125 I can't contribute anytime soon. I'm certainly not a project maintainer, but the ideal-for-contribution label makes me think they'd be okay with a PR from you. :)

[philwebb]

@marti1125 Yes please, that would be most welcome.

[Chuck-Norris-with-thesaurus]

I have tried this in Spring Boot 2.0.0.RC1 and swagger-ui 3.9.3 - can't reproduce the problem. Has it been solved?

[wilkinsona]

@Butorchin-Dmitri Not that we're aware of; nothing's change in Boot to support this. Can you share your app that appears to work?

[jessemillar]

@Butorchin-Dmitri Were you trying with Jersey instead of the default Spring Boot container? I can throw together a quick demo that shows the issue today.

Edit: I'd forgotten that my team has moved away from Spring Boot for this particular project which means I no longer have a codebase to quickly make a demo from. Perhaps @Butorchin-Dmitri's new app is working as intended.

[w4tson]

I've managed to replicate some of the issue in a git repo. Instructions to reproduce are in the README.

I've done some analysis on this and would like to help fix.

As @philwebb mentioned the webjars functionality is getting implemented by org.springframework.web.servlet.resource.WebJarsResourceResolver. Unfortunately this is in the spring-mvc project and leverages the ResourceResolver mechanism which isn't available to spring-jersey users.

I've dreamt up a couple of options

1. Allow the servlet 3.0 convention to statically serve webjars
2. A Jersey controller with regex of /webjars/.* to serve content
3. A servlet/filter that does the same

By all accounts a servlet 3.0 should serve static files in the META-INF/resources directory. The webjars documentation explains as such. I just can't get this to work. Tried adding in the Tomcat DefaultServlet and setting Jersey to be a Filter but no joy.

Can someone steer me in the right direction?

[Chuck-Norris-with-thesaurus]

@w4tson If you run it with 2.0.0.RC1 the access with version works: http://localhost:8080/webjars/swagger-ui/3.6.1/index.html, although it doesn't work without it, as reported in the original post - I was confused somehow.
https://github.com/Butorchin-Dmitri/spring-boot-jersey