Swagger UI redirecting to /swagger-ui/index.html?configUrl=/v3/api-docs/swagger-config

this is not about the redirect, as it works to just open to http://localhost:8080/swagger-ui/index.html. But some answers are about disabling the petshop and configUrl. Supplying configUrl is not working anymore for a autoconfigured springdoc. Overwriting the url, config-url (if needed) and default url works with the following application.yml:

springdoc:
  swagger-ui:
    url: "/v3/api-docs"
    disable-swagger-default-url: true

or you can use the topics plugin:

springdoc:
  swagger-ui:
    disable-swagger-default-url: true
    urls:
      - url: "/v3/api-docs"
        name: "myService"

I also encountered this issue because our app is behind a gateway/load balancer and on Docker. My goal is to really just access the Swagger UI and my workaround is to access /swagger-ui/index.html directly. It loads the "Swagger Petstore". In the "Explore" field, I type /v3/api-docs to load my application's APIs.

I had same problem with redirect to /swagger-ui/index.html with status code 404. In my kotlin project. My problem was that I used custom configuration extends WebMvcConfigurationSupport:

@Configuration
class CustomConfig() : WebMvcConfigurationSupport() {...}

So I had to update that config like this and it works! :)

@Configuration
class CustomConfig(
    private val swaggerIndexTransformer: SwaggerIndexTransformer
) : WebMvcConfigurationSupport() {

    public override fun addResourceHandlers(registry: ResourceHandlerRegistry) {
        registry.addResourceHandler("/swagger-ui*/**")
            .addResourceLocations("classpath:/META-INF/resources/webjars/")
            .resourceChain(false)
            .addTransformer(swaggerIndexTransformer)

        super.addResourceHandlers(registry)
    }
}

I found a post to workaround for this. Scan and modify the index.html to replace petStore URL for apiDoc URL

    @Configuration

    public class DocOpenApiConfiguration implements WebMvcConfigurer {

    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("/**/*.html")
                .addResourceLocations("classpath:/META-INF/resources/webjars/")
                .resourceChain(false)
                .addResolver(new WebJarsResourceResolver())
                .addResolver(new PathResourceResolver())
                .addTransformer(new IndexPageTransformer());
    }

    public static class IndexPageTransformer implements ResourceTransformer {

        private String overwriteDefaultUrl(String html) {
            return html.replace("https://petstore.swagger.io/v2/swagger.json",
                    "/v3/api-docs");
        }

        @Override
        public Resource transform(HttpServletRequest httpServletRequest, Resource resource, ResourceTransformerChain resourceTransformerChain) throws IOException {
            if (resource.getURL().toString().endsWith("/index.html")) {
                String html = IOUtils.toString(resource.getInputStream(), StandardCharsets.UTF_8);
                html = overwriteDefaultUrl(html);
                return new TransformedResource(resource, html.getBytes());
            } else {
                return resource;
            }
        }
    }
}