Keycloak integration in Swagger

Question

I have a Keycloak protected backend that I would like to access via swagger-ui. Keycloak provides the oauth2 implicit and access code flow, but I was not able to make it wor

Answer 1

Swagger-ui + Keycloak (or any other OAuth2 provider) using implicit flow, OpenAPI 3.0 template:

components:
  ...
   securitySchemes:
    my_auth_whatever:
      type: oauth2
      flows:
        implicit:
          authorizationUrl: https://MY-KEYCLOAK-HOST/auth/realms/MY-REALM-ID/protocol/openid-connect/auth
          scopes: {}
  ...
security:
  - my_auth_whatever: []

Make sure the implicit flow is enabled in Keycloak settings for the client that you use.

One downside is that the user is still asked for client_id in the modal when clicks on "Authorize" button in Swagger UI. The value that user enters may be overwritten by adding query param ?client_id=YOUR-CLIENT-ID to the authorizationUrl but it's kinda the dirty hack and the modal is still showed to the user. When running swagger-ui in docker - the OAUTH_CLIENT_ID env var may be provided to container to set the default client_id value for the modal. For non-docker deployment refer to @wargre's approach with changing the index.html (not sure if there's a better way).

For SwaggerAPI (OpenAPI 2.0) example refer to first code snippet in @wargre's answer and this doc: https://swagger.io/docs/specification/2-0/authentication/

Answer 2

Swagger-ui can integrate with keycloak using the implicit authentication mode. You can setup oauth2 on swagger-ui so that it will ask you to authenticate instead of giving swagger-ui the access token directly.

1st thing, your swagger need to reference a Security definition like:

"securityDefinitions": {
    "oauth2": {
        "type":"oauth2",
        "authorizationUrl":"http://172.17.0.2:8080/auth/realms/master/protocol/openid-connect/auth",
        "flow":"implicit",
        "scopes": {
            "openid":"openid",
            "profile":"profile"
        }
    }
}

Then, you swagger-ui need to reference some other parameter: With the pure js, you can use in the index.html

const ui = SwaggerUIBundle({ ...} );

ui.initOAuth({
    clientId: "test-uid",
    realm: "Master",
    appName: "swagger-ui",
    scopeSeparator: " ",
    additionalQueryStringParams: {"nonce": "132456"}
})

In this code,

• authorizationUrl is the authorization endpoint on your keycloak realm
• Scopes are something you can set to your needs
• clientId is a client parametrized with implicit mode on keycloak realm
• the additional parameter nonce should be random, but swagger-ui don't use it yet.

I add here an example if you want to do all this on Spring-boot:

On this framework, you will mainly use swagger and swagger-ui web-jar from Springfox. This is done by adding the dependencies:

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.8.0</version>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.8.0</version>
</dependency>

Swagger is enable by adding the annotation swagger2 on your main class:

@SpringBootApplication
@EnableSwagger2
public class TestSpringApplication {
    ...

then you can setup a Configuration class like this:

@Configuration
public class SwaggerConfigurer {

    @Bean
    public SecurityConfiguration securityConfiguration() {

        Map<String, Object> additionalQueryStringParams=new HashMap<>();
        additionalQueryStringParams.put("nonce","123456");

        return SecurityConfigurationBuilder.builder()
            .clientId("test-uid").realm("Master").appName("swagger-ui")
            .additionalQueryStringParams(additionalQueryStringParams)
            .build();
    }

    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
            .select()
            .apis(RequestHandlerSelectors.basePackage("com.example.testspring"))
            .paths(PathSelectors.any())
            .build().securitySchemes(buildSecurityScheme()).securityContexts(buildSecurityContext());
    }

    private List<SecurityContext> buildSecurityContext() {
        List<SecurityReference> securityReferences = new ArrayList<>();

        securityReferences.add(SecurityReference.builder().reference("oauth2").scopes(scopes().toArray(new AuthorizationScope[]{})).build());

        SecurityContext context = SecurityContext.builder().forPaths(Predicates.alwaysTrue()).securityReferences(securityReferences).build();

        List<SecurityContext> ret = new ArrayList<>();
        ret.add(context);
        return ret;
    }

    private List<? extends SecurityScheme> buildSecurityScheme() {
        List<SecurityScheme> lst = new ArrayList<>();
        // lst.add(new ApiKey("api_key", "X-API-KEY", "header"));

        LoginEndpoint login = new LoginEndpointBuilder().url("http://172.17.0.2:8080/auth/realms/master/protocol/openid-connect/auth").build();

        List<GrantType> gTypes = new ArrayList<>();
        gTypes.add(new ImplicitGrant(login, "acces_token"));

        lst.add(new OAuth("oauth2", scopes(), gTypes));
        return lst;
    }

    private List<AuthorizationScope> scopes() {
        List<AuthorizationScope> scopes = new ArrayList<>();
        for (String scopeItem : new String[]{"openid=openid", "profile=profile"}) {
            String scope[] = scopeItem.split("=");
            if (scope.length == 2) {
                scopes.add(new AuthorizationScopeBuilder().scope(scope[0]).description(scope[1]).build());
            } else {
                log.warn("Scope '{}' is not valid (format is scope=description)", scopeItem);
            }
        }

        return scopes;
    }
}

There is a lot of thing you can update in this code. This is mainly the same as before:

• nonce which should be a random thing (swagger-ui don't use it yet)
• clientId which you need to setup accordingly to the client you setup in keycloak
• basePackage: You need to set the package in which all your controller are
• If you need an api-key, you can enable it and add it on the security scheme list
• LoginEndpoint: that need to be the authorization endpoint of you keycloak realm
• scopeItems: the scopes you want for this authentication.

It will generate the same thing as before: Updating the swagger to add the securityDefinition and make swagger-UI take the parameter for clientId, nonce, ...

Answer 3

Was struggling with this setup for the past 2 days. Finally got a working solution for those who cannot resolve.

pom.xml

    ...
    <dependency>
        <groupId>org.keycloak</groupId>
        <artifactId>keycloak-spring-security-adapter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.keycloak</groupId>
        <artifactId>keycloak-spring-boot-starter</artifactId>
    </dependency>
    ...

Enable Swagger on main class

...    
import springfox.documentation.swagger2.annotations.EnableSwagger2;

@SpringBootApplication
@EnableSwagger2
@EnableAsync
@EnableCaching
public class MainApplication {
  public static void main(String[] args) {
    SpringApplication app = new SpringApplication(MainApplication.class);
    app.run(args);
  }
}

SwaggerConfig.java

package com.XXX.XXXXXXXX.app.config;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import springfox.documentation.builders.ApiInfoBuilder;
import springfox.documentation.builders.AuthorizationCodeGrantBuilder;
import springfox.documentation.builders.OAuthBuilder;
import springfox.documentation.builders.PathSelectors;
import springfox.documentation.service.*;
import springfox.documentation.spi.DocumentationType;
import springfox.documentation.spi.service.contexts.SecurityContext;
import springfox.documentation.spring.web.plugins.Docket;
import springfox.documentation.swagger.web.SecurityConfiguration;
import springfox.documentation.swagger.web.SecurityConfigurationBuilder;
import springfox.documentation.swagger2.annotations.EnableSwagger2;

import java.util.Arrays;

import static springfox.documentation.builders.PathSelectors.regex;

/*
 * Setting up Swagger for spring boot
 * https://www.baeldung.com/swagger-2-documentation-for-spring-rest-api
 */
@Configuration
@EnableSwagger2
public class SwaggerConfig {

 @Value("${keycloak.auth-server-url}")
 private String AUTH_SERVER;

 @Value("${keycloak.credentials.secret}")
 private String CLIENT_SECRET;

 @Value("${keycloak.resource}")
 private String CLIENT_ID;

 @Value("${keycloak.realm}")
 private String REALM;

 private static final String OAUTH_NAME = "spring_oauth";
 private static final String ALLOWED_PATHS = "/directory_to_controllers/.*";
 private static final String GROUP_NAME = "XXXXXXX-api";
 private static final String TITLE = "API Documentation for XXXXXXX Application";
 private static final String DESCRIPTION = "Description here";
 private static final String VERSION = "1.0";

 @Bean
 public Docket taskApi() {
   return new Docket(DocumentationType.SWAGGER_2)
    .groupName(GROUP_NAME)
    .useDefaultResponseMessages(true)
    .apiInfo(apiInfo())
    .select()
    .paths(regex(ALLOWED_PATHS))
    .build()
    .securitySchemes(Arrays.asList(securityScheme()))
    .securityContexts(Arrays.asList(securityContext()));
 }

 private ApiInfo apiInfo() {
   return new 
     ApiInfoBuilder().title(TITLE).description(DESCRIPTION).version(VERSION).build();
 }

 @Bean
 public SecurityConfiguration security() {
   return SecurityConfigurationBuilder.builder()
    .realm(REALM)
    .clientId(CLIENT_ID)
    .clientSecret(CLIENT_SECRET)
    .appName(GROUP_NAME)
    .scopeSeparator(" ")
    .build();
 }

 private SecurityScheme securityScheme() {
   GrantType grantType =
    new AuthorizationCodeGrantBuilder()
        .tokenEndpoint(new TokenEndpoint(AUTH_SERVER + "/realms/" + REALM + "/protocol/openid-connect/token", GROUP_NAME))
        .tokenRequestEndpoint(
            new TokenRequestEndpoint(AUTH_SERVER + "/realms/" + REALM + "/protocol/openid-connect/auth", CLIENT_ID, CLIENT_SECRET))
        .build();

SecurityScheme oauth =
    new OAuthBuilder()
        .name(OAUTH_NAME)
        .grantTypes(Arrays.asList(grantType))
        .scopes(Arrays.asList(scopes()))
        .build();
return oauth;
 }

 private AuthorizationScope[] scopes() {
AuthorizationScope[] scopes = {
  new AuthorizationScope("user", "for CRUD operations"),
  new AuthorizationScope("read", "for read operations"),
  new AuthorizationScope("write", "for write operations")
};
return scopes;
}

private SecurityContext securityContext() {
return SecurityContext.builder()
    .securityReferences(Arrays.asList(new SecurityReference(OAUTH_NAME, scopes())))
    .forPaths(PathSelectors.regex(ALLOWED_PATHS))
    .build();
 }
}

From terminal, run "mvnw spring-boot:run"

Open browser and hit http://localhost:[port]/[app_name]/swagger-ui.html.

Click the Authorize button: Swagger Authorize Button

This should present a modal to confirm your keycloak settings.

Click Authorize button once again. You should be redirected to a login screen.

Once credentials are entered and confirmed, you will be redirected back to Swagger-UI fully authenticated.