Keycloak integration in Swagger

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, …