How to inject a custom header whenever a request is sent from Swagger UI?

Question

I have a situation when I would like to hard-code a request header called test-header which will store simple JSON data {"username":"swagger", "email":"dummy@email"}. So the users who will use Swagger UI to make requests won't need to add this data manually, it will always be automatically added to each request sent from Swagger UI.

I am using org.springdoc with Spring Boot v3. And currently I just have simple OpenAPI bean:

@Bean
public OpenAPI customOpenAPI(@Value("${springdoc.version}") String appVersion) {
    return new OpenAPI()
            .info(new Info().title("Person API").version(appVersion)
                    .license(new License().name("Apache 2.0").url("http://springdoc.org")));
};

Is there a possibility to add it somehow to it? Or am I fated to use a filter/interceptor?

How would your production code look then? Would that still have that test header included and would that be branching off somehow? Typically you read header as method params. — mbodev, Mar 05 '23 at 14:55
Yes, production code would have the same header, but it would be added with third party service. There wouldnt be any authentication within current service, the information are needed only to store them in database, whenever some data was created/modified. I would like to avoid ppl to add it by hand with swagger, as there might be much more data then just `username` and `email` — Suule, Mar 05 '23 at 15:12
In standalone Swagger UI it can be done using the `requestInterceptor` as [shown here](https://stackoverflow.com/q/46485621/113116). Since you're using Springdoc, you can try adding the `requestInterceptor` [as suggested here](https://github.com/springdoc/springdoc-openapi/issues/1654#issuecomment-1121621044). — Helen, Mar 06 '23 at 08:33

Ritik Sharma · Accepted Answer · 2023-03-06T21:10:53.957

Yes, it's possible to pass a custom header with some default value through Swagger UI. You can use the below code snippet to customize OpenAPI -

@Bean
public OpenApiCustomizer getCustomizer() {
    ObjectSchema myCustomSchema = new ObjectSchema();
    myCustomSchema.addProperty("username", new Schema<>().type("string")._default("swagger"));
    myCustomSchema.addProperty("email", new Schema<>().type("string")._default("dummy@email"));

    return openApi -> openApi.getPaths().values().stream()
            .flatMap(pathItem -> pathItem.readOperations().stream())
            .forEach(operation -> 
                operation.addParametersItem(
                        new HeaderParameter()
                                .name("test-header")
                                .required(false)
                                .schema(myCustomSchema).explode(true)
                                .style(Parameter.StyleEnum.SIMPLE)
                )
            );
}

This will produce your header's value in the controller as username=swagger,email=dummy@email.

But I'll suggest if you have to pass a JSON as a header then pass it in stringified, and parse it to an object in your controller. For string type header, OpenAPI can be customized as -

 @Bean
public OpenApiCustomizer getCustomizer() {
    return openApi -> openApi.getPaths().values().stream()
            .flatMap(pathItem -> pathItem.readOperations().stream())
            .forEach(operation -> operation
                    .addParametersItem(
                            new HeaderParameter()
                                    .name("test-header")
                                    .required(false)
                                    .schema(new Schema().type("string")._default("{\"username\":\"swagger\", \"email\":\"dummy@email\"}"))
                    ));
}

Please upvote if it helps.

How to inject a custom header whenever a request is sent from Swagger UI?

1 Answers1