No documented way to handle Mono/Flux without Webflux

Describe the bug

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To Reproduce I have Spring MVC (no spring-webflux) application based on Spring Boot 2.2.6 and Springdoc 1.3.0.

My controllers return Flux and Mono.

By default springdoc’s swagger-ui page displays Flux response as:

{
  "prefetch": 0
}

When I include org.springdoc:springdoc-openapi-webflux-core:1.3.0 my application fails to start:

***************************
APPLICATION FAILED TO START
***************************

Description:

An attempt was made to call a method that does not exist. The attempt was made from the following location:

    org.springdoc.core.SpringDocWebMvcConfiguration.openApiResource(SpringDocWebMvcConfiguration.java:60)

The following method did not exist:

    'void org.springdoc.api.OpenApiResource.<init>(java.lang.String, org.springdoc.core.OpenAPIBuilder, org.springdoc.core.AbstractRequestBuilder, org.springdoc.core.GenericResponseBuilder, org.springdoc.core.OperationBuilder, org.springframework.web.servlet.mvc.method.RequestMappingInfoHandlerMapping, java.util.Optional, java.util.Optional, org.springdoc.core.SpringDocConfigProperties, java.util.Optional)'

The method's class, org.springdoc.api.OpenApiResource, is available from the following locations:

    jar:file:/home/pkubowicz/.gradle/caches/modules-2/files-2.1/org.springdoc/springdoc-openapi-webflux-core/1.3.0/9254ae87d259128c266dcb64a8fdefefa776fbcb/springdoc-openapi-webflux-core-1.3.0.jar!/org/springdoc/api/OpenApiResource.class
    jar:file:/home/pkubowicz/.gradle/caches/modules-2/files-2.1/org.springdoc/springdoc-openapi-webmvc-core/1.3.0/13bab9bda41e79dbc041c5fb4e564548e7cd0ffd/springdoc-openapi-webmvc-core-1.3.0.jar!/org/springdoc/api/OpenApiResource.class

The work-around is to execute:

SpringDocUtils.getConfig().addResponseWrapperToIgnore(Mono::class.java)
SpringDocUtils.getConfig().addResponseWrapperToIgnore(Flux::class.java)

Expected behavior This use case should be documented - should springdoc-openapi-webflux-core be used or not used, and if not the documentation should explain how to ‘unwrap’ Flux and Mono.

[mnbattaglia]

Is this still unsupported? I agree with others that this is a totally valid use case and must be supported

[iyzana]

I’ve run into the same problem. springdoc-openai-webmvc-core should be able to handle Mono and Flux return types too.

The suggested workaround above is not sufficient for Flux, because just stripping it is not correct, it should be handled as an array. As a further workaround I had to annotate all endpoints returning a Flux with:

@Operation(responses = @ApiResponse(content = @Content(array = @ArraySchema(schema = @Schema(implementation = String.class)))))