Springfox swagger-ui.html unable to infer base URL - Caused by missing cookies

Question

We have our Spring Boot services behind an API Gateway. With an earlier version of Springfox - 2.1.2 we had no issues in loading the swagger-ui.html page. This worked with Spring Boot 1.4.3.RELEASE. From then, we have upgraded to Boot 1.5.7 and upgraded Springfox to 2.8.0.

Now if we load the page we get an alert box with the following long message.

Unable to infer base url. This is common when using dynamic servlet registration or when the API is behind an API Gateway. The base url is the root of where all the swagger resources are served. For e.g. if the api is available at http://example.org/api/v2/api-docs then the base url is http://example.org/api/. Please enter the location manually

I got some hints searching online, but it does not seem those situations apply to us. For one, if I simply revert back the versions, it starts working again through the same API Gateway.

Tracking the traffic, it seems calls to three XHR resources made by the .html page is causing issues. These are returning 401 from our API gateway. And the reason they return 401 is because the cookies are not passed along.

The three calls are:

• https://base_address/base_context/swagger-resources/configuration/ui
• https://base_address/base_context/swagger-resources/configuration/security
• https://base_address/base_context/swagger-resources

If I load these URLs as pure browser requests - they work - because cookies are sent.

I doubt if CORS applies since the HTML is being served from the same address as the swagger JSON and actual service calls.

Any idea why this may be happening? Anybody faced similar issues? Suggestions for workaround? Thanks much in advance.

Solution 1

Add in the security config -- following URLS that are skipped for authentication ::

private static final String[] AUTH_WHITELIST = {
        "/swagger-resources/**",
        "/swagger-ui.html",
        "/v2/api-docs",
        "/webjars/**"
};

@Override
public void configure(WebSecurity web) throws Exception {
    web.ignoring().antMatchers(AUTH_WHITELIST);
}

Solution 2

Adding below annotation at the spring boot class resolved this issue for me.

@EnableSwagger2

I am using swagger version

 <version>2.9.2</version>

Solution 3

SEE EDIT BELOW

Do you use spring security?

If yes, probably you skip some resources like this (right?): "/swagger-resources/**", "/swagger-ui.html", "/v2/api-docs", "/webjars/**"

Try to change it "/swagger-resources/**" to "**/swagger-resources/**".

My specific security config for swagger is:

private static final String[] AUTH_LIST = {
        // -- swagger ui
        "**/swagger-resources/**",
        "/swagger-ui.html",
        "/v2/api-docs",
        "/webjars/**"
};

@Override
protected void configure(HttpSecurity http) throws Exception {
    http
    .authorizeRequests().antMatchers(AUTH_LIST).authenticated()
    .and()
    .httpBasic().authenticationEntryPoint(swaggerAuthenticationEntryPoint())
    .and()
    .csrf().disable();
}

@Bean
public BasicAuthenticationEntryPoint swaggerAuthenticationEntryPoint() {
    BasicAuthenticationEntryPoint entryPoint = new BasicAuthenticationEntryPoint();
    entryPoint.setRealmName("Swagger Realm");
    return entryPoint;
}

If you need/want I can send a sample project to GitHub to you know more about my security/swagger configs.

EDIT 2018/04/10

This problem is caused by a wrong version in springfox. See this issue on github to solve the problem.

To posterity:

In pom.xml

...
<repositories>
    <repository>
        <id>swagger</id>
        <name>swagger</name>
        <url>http://oss.jfrog.org/artifactory/oss-snapshot-local</url>
    </repository>
</repositories>
...
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.8.1-SNAPSHOT</version>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.8.1-SNAPSHOT</version>
</dependency>
...

Class that extends WebSecurityConfigAdapter:

@Configuration
public class WebSecurityConfigEntryPointApplication extends WebSecurityConfigurerAdapter {

    private static final List<String> AUTH_LIST = Arrays.asList(
            "/swagger-resources/**",
            "/swagger-ui.html**",
            "/webjars/**",
            "favicon.ico");

    @Autowired
    private RestAuthenticationEntryPoint restAuthenticationEntryPoint;

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
                .antMatcher("/**").authorizeRequests().anyRequest().authenticated()
                .and()
                .exceptionHandling()
                .defaultAuthenticationEntryPointFor(swaggerAuthenticationEntryPoint(), new CustomRequestMatcher(AUTH_LIST))
                .and()
                .httpBasic()
                .authenticationEntryPoint(restAuthenticationEntryPoint)
                .and()
                .csrf().disable();
    }

    @Bean
    public BasicAuthenticationEntryPoint swaggerAuthenticationEntryPoint() {
        BasicAuthenticationEntryPoint entryPoint = new BasicAuthenticationEntryPoint();
        entryPoint.setRealmName("Swagger Realm");
        return entryPoint;
    }

    private class CustomRequestMatcher implements RequestMatcher {

        private List<AntPathRequestMatcher> matchers;

        private CustomRequestMatcher(List<String> matchers) {
            this.matchers = matchers.stream().map(AntPathRequestMatcher::new).collect(Collectors.toList());
        }

        @Override
        public boolean matches(HttpServletRequest request) {
            return matchers.stream().anyMatch(a -> a.matches(request));
        }

    }

}

RestAuthenticationEntryPoint:

@Component
public class RestAuthenticationEntryPoint implements AuthenticationEntryPoint {

    @Override
    public void commence(HttpServletRequest request, HttpServletResponse response, AuthenticationException authException) throws IOException {
        response.sendError(HttpServletResponse.SC_UNAUTHORIZED, "Unauthorized");
    }
}

Solution 4

This happened to me, I was using SpringBoot 1.5.16 and Springfox 2.9.1.

In my application.properties, I had defined server.servlet-path=/api, but, somehow, the swagger-ui was ignoring the value defined. I've tried so many different way to make this work, and finally I found a workaround:

 @Configuration
 @EnableSwagger2
 public class SwaggerConfiguration extends WebMvcConfigurationSupport {                                    

    @Bean
    public Docket apiMonitoramento() { 
        return new Docket(DocumentationType.SWAGGER_2)
                .select()                                  
                .apis(RequestHandlerSelectors.any())
                .paths(PathSelectors.any())                          
                .build()    
                .apiInfo(apiInfo());
    }

    private ApiInfo apiInfo() {
        return new ApiInfoBuilder()              
                .title("REST API")
                .description("Servicesx")               
                .build();
    }

    @Override
    protected void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");
        registry.addResourceHandler("/webjars/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/");
    }
 }

I was accessing http://localhost:8080/context/swagger-ui.html, but with that configuration the correct URL is: http://localhost:8080/context/api/swagger-ui.html

Solution 5

In my case, the cause of the problem was having:

@ComponentScan(basePackageClasses = {ApplicationRoot.class })

twice in two java files.

after removing the extra one, the problem went away.

View more solutions

Comments

[Arnab Gupta]

I have these set up. The issue is actually with 2.8.0 itself. I filed issue here: github.com/springfox/springfox/issues/2281

[Marco Blos]

Hi @ArnabGupta. You are right! I made one comment on github with all steps to solve this problem. You get it here: github.com/springfox/springfox/issues/2191

[David Bradley]

FWIW This worked for SpringFox 3.0 for me. I added /swagger-ui/** since, at least for me, the URL is /swagger-ui/index.html. Didn't seem to need the webjars path, but I might have just not hit that yet.