2. Setup

OpenAPI plugin for Javalin with Swagger UI:

Javalin.createAndStart(config -> {
    config.registerPlugin(new OpenApiPlugin(openApiConfig ->
        openApiConfig
            .withDocumentationPath("/openapi.json")
            .withRoles(Rules.ANONYMOUS)
            .withDefinitionConfiguration((version, openApiDefinition) ->
                openApiDefinition
                    .withInfo(openApiInfo ->
                        openApiInfo
                            .description("App description goes right here")
                            .termsOfService("https://example.com/tos")
                            .contact("API Support", "https://www.example.com/support", "[email protected]")
                            .license("Apache 2.0", "https://www.apache.org/licenses/", "Apache-2.0")
                    )
                    .withServer(openApiServer ->
                        openApiServer
                            .description("Server description goes here")
                            .url("http://localhost:{port}{basePath}/" + version + "/")
                            .variable("port", "Server's port", "8080", "8080", "7070")
                            .variable("basePath", "Base path of the server", "", "", "v1")
                    )
                    // Based on official example: https://swagger.io/docs/specification/authentication/oauth2/
                    .withSecurity(openApiSecurity ->
                        openApiSecurity
                            .withBasicAuth()
                            .withBearerAuth()
                            .withApiKeyAuth("ApiKeyAuth", "X-Api-Key")
                            .withCookieAuth("CookieAuth", "JSESSIONID")
                            .withOpenID("OpenID", "https://example.com/.well-known/openid-configuration")
                            .withOAuth2("OAuth2", "This API uses OAuth 2 with the implicit grant flow.", oauth2 ->
                                oauth2
                                    .withClientCredentials("https://api.example.com/credentials/authorize")
                                    .withImplicitFlow("https://api.example.com/oauth2/authorize", flow ->
                                        flow
                                            .withScope("read_pets", "read your pets")
                                            .withScope("write_pets", "modify pets in your account")
                                    )
                            )
                            .withGlobalSecurity("OAuth2", globalSecurity ->
                                globalSecurity
                                    .withScope("write_pets")
                                    .withScope("read_pets")
                            )
                    )
                    .withDefinitionProcessor(content -> { // you can add whatever you want to this document using your favourite json api
                        content.set("test", new TextNode("Value"));
                        return content.toPrettyString();
                    })
            )));

    config.registerPlugin(new SwaggerPlugin(swaggerConfiguration -> {
        swaggerConfiguration.setDocumentationPath(deprecatedDocsPath);
    }));

    config.registerPlugin(new ReDocPlugin(reDocConfiguration -> {
        reDocConfiguration.setDocumentationPath(deprecatedDocsPath);
    }));

    for (JsonSchemaResource generatedJsonSchema : new JsonSchemaLoader().loadGeneratedSchemes()) {
        System.out.println(generatedJsonSchema.getName());
        System.out.println(generatedJsonSchema.getContentAsString());
    }
});

Full example:

• https://github.com/javalin/javalin-openapi/blob/main/examples/javalin-gradle-kotlin/src/main/java/io/javalin/openapi/plugin/test/JavalinTest.java