Failed to load API definition on URL /v3/api-docs/ (HTTP 404 not found error)

[rasenderhase]

Describe the bug

The swagger-ui frontend tries to load the openapi data from the URL

/v3/api-docs/ with trailing slash.

The backend resource OpenApiWebMvcResource listens per default on /v3/api-docs without trailing slash.

In fact, the URL /v3/api-docs/ gets mapped wrongly by Spring:

2023-08-03 14:28:42,652 DEBUG [http-nio-8080-exec-1][][] o.s.s.w.FilterChainProxy: Secured GET /v3/api-docs/
2023-08-03 14:28:42,657 DEBUG [http-nio-8080-exec-1][][] o.s.w.s.DispatcherServlet: GET "/my-application/v3/api-docs/", parameters={}
2023-08-03 14:28:44,604 DEBUG [http-nio-8080-exec-1][][] o.s.w.s.h.SimpleUrlHandlerMapping: Mapped to ResourceHttpRequestHandler [classpath [META-INF/resources/], classpath [resources/], classpath [static/], classpath [public/], ServletContext [/]]
2023-08-03 14:28:45,977 DEBUG [http-nio-8080-exec-1][][] o.s.w.s.r.ResourceHttpRequestHandler: Resource not found

So the frontend displays the error response status is 404 /my-application/v3/api-docs/.

I am using...

 org.springdoc:springdoc-openapi-starter-webmvc-ui:2.1.0
 org.springframework.boot:spring-boot-gradle-plugin:3.1.2

Maybe the issue is caused by this change in Spring:

https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/servlet/config/annotation/PathMatchConfigurer.html#setUseTrailingSlashMatch(java.lang.Boolean)

The Spring framework is now more precise per default handling URLs. I think the controller that is providing the swagger-config should be adapted. Currently it adds a trailing slash to the 1st url in the urls array:

{
    "configUrl": "/my-application/v3/api-docs/swagger-config",
    "defaultModelExpandDepth": "10",
    "defaultModelRendering": "model",
    "defaultModelsExpandDepth": "-1",
    "docExpansion": "full",
    "oauth2RedirectUrl": "http://127.0.0.1:16071/my-application/swagger-ui/oauth2-redirect.html",
    "urls": [
        {
            "url": "/my-application/v3/api-docs/",
            "name": ""
        },
        {
            "url": "/my-application/v3/api-docs/api",
            "name": "api"
        }
    ],
    "validatorUrl": ""
}

[uc4w6c]

Please provide a Minimal, Reproducible Example - with HelloController that reproduces the issue.

[rasenderhase]

I have created a demo project. And of course it works... ;-)

However, the response of http://localhost:8080/v3/api-docs/swagger-config looks different in the demo project:

{
    "configUrl": "/v3/api-docs/swagger-config",
    "oauth2RedirectUrl": "http://localhost:8080/swagger-ui/oauth2-redirect.html",
    "url": "/v3/api-docs",
    "validatorUrl": ""
}

In the project with the issue, the property url is not present, instead there is the property urls which is an array. How can I achieve that in the demo project? Maybe that is causing the issue...?

[rasenderhase]

I have added the OpenApiConfig we are using, and that introduces the issue. see rasenderhase/demo-api-docs-issue@d5e2266

[uc4w6c]

Thank you.
But it returns 404.
private repository?

[rasenderhase]

Now it's public. Sorry for that.

[bnasslahsen]

@rasenderhase,

The group Name cannot be null or empty.
I have updated the rule for the future release so there is no misunderstanding.

[EdgardHernandezp]

I'm having the same problem, apparently this was closed and fixed but I don't understand whats the workaround. I'm using version 2.2.0

[rasenderhase]

If you are using config, check if the group name is empty. That is not allowed:

@Bean
public GroupedOpenApi all() {
    return createDefaultGroupedOpenApi("", "/**");
}

[EdgardHernandezp]

I understand but in my case all I did was add the dependency and exclude from the authorization flow this paths:

/swagger-ui.html
/swagger-ui/**
/v3/api-docs/**
/v3/api-docs.yaml
/swagger-resources
/swagger-resources/**
/configuration/ui
/configuration/security
/swagger-ui/**
/webjars/**

I have not made any extra swagger related config. At this point it should be working :(