Mandatory header for all API in openapi 3.0

Question

I am using OpenAPI 3.0 with Spring-boot 5 and therefore have no configuration YAML. I have a header that contains the client Identification ID(This is not an authentication header). I want to make that a mandatory header param. Added below OpenAPI configuration

@Configuration
public class OpenAPIConfiguration {
    @Bean
    public OpenAPI customOpenAPI() {

        return new OpenAPI()
                .components(new Components()
                        .addParameters("myCustomHeader", new Parameter().in("header").schema(new StringSchema()).required(true).description("myCustomHeader").name("myCustomHeader")))
                .info(new Info()
                        .title("My Rest Application")
                        .version("1.2.26"));
    }
}

However, the swagger UI does not show the required param in any API. Can someone help as to what I am doing wrong?

Answer 1

Adding parameter definition to a custom OpenAPI bean will not work because the parameter won't get propagated to the operations definitions. You can achieve your goal using OperationCustomizer:

    @Bean
    public OperationCustomizer customize() {
        return (operation, handlerMethod) -> operation.addParametersItem(
                new Parameter()
                        .in("header")
                        .required(true)
                        .description("myCustomHeader")
                        .name("myCustomHeader"));
    }

The OperationCustomizer interface was introduced in the springdoc-openapi 1.2.22. In previous versions you would need to use OpenApiCustomiser:

@Component
public class MyOpenApiCustomizer implements OpenApiCustomiser {

    private static final List<Function<PathItem, Operation>> OPERATION_GETTERS = Arrays.asList(
            PathItem::getGet, PathItem::getPost, PathItem::getDelete, PathItem::getHead,
            PathItem::getOptions, PathItem::getPatch, PathItem::getPut);

    private Stream<Operation> getOperations(PathItem pathItem) {
        return OPERATION_GETTERS.stream()
                .map(getter -> getter.apply(pathItem))
                .filter(Objects::nonNull);
    }

    @Override
    public void customise(OpenAPI openApi) {
        openApi.getPaths().values().stream()
                .flatMap(this::getOperations)
                .forEach(this::customize);
    }

    private void customize(Operation operation) {
        operation.addParametersItem(
                new Parameter()
                        .in("header")
                        .required(true)
                        .description("myCustomHeader")
                        .name("myCustomHeader"));
    }
}