Server Developer Guide

A theme can provide one or more types to customize different aspects of Red Hat build of Keycloak. The types available are:

All theme types, except welcome, are configured through the Admin Console.

Red Hat build of Keycloak comes bundled with default themes in the JAR file keycloak-themes-24.0.8.redhat-00001.jar inside the server distribution. The server’s root themes directory does not contain any themes by default, but it contains a README file with some additional details about the default themes. To simplify upgrading, do not edit the bundled themes directly. Instead create your own theme that extends one of the bundled themes.

A theme consists of:

Unless you plan to replace every single page you should extend another theme. Most likely you will want to extend some existing theme. Alternatively, if you intend to provide your own implementation of the admin or account console, consider extending the base theme. The base theme consists of a message bundle and therefore such implementation needs to start from scratch, including implementation of the main index.ftl Freemarker template, but it can leverage existing translations from the message bundle.

When extending a theme you can override individual resources (templates, stylesheets, etc.). If you decide to override HTML templates bear in mind that you may need to update your custom template when upgrading to a new release.

While creating a theme it’s a good idea to disable caching as this makes it possible to edit theme resources directly from the themes directory without restarting Red Hat build of Keycloak.

javaVersion=${java.version}

unixHome=${env.HOME:Unix home not found}
windowsHome=${env.HOMEPATH:Windows home not found}

body {
    background-image: url('../img/image.jpg');
    background-size: cover;
}

<img src="${url.resourcesPath}/img/image.jpg" alt="My image description">

<img src="${url.resourcesUrl}/img/image.jpg" alt="My image description">

usernameOrEmail=Your Username

passwordResetSubject=My password recovery
passwordResetBody=Reset password link: {0}
passwordResetBodyHtml=<a href="{0}">Reset password</a>

Themes can be deployed to Red Hat build of Keycloak by copying the theme directory to themes or it can be deployed as an archive. During development you can copy the theme to the themes directory, but in production you may want to consider using an archive. An archive makes it simpler to have a versioned copy of the theme, especially when you have multiple instances of Red Hat build of Keycloak for example with clustering.

To deploy the archive to Red Hat build of Keycloak, add it to the providers/ directory of Red Hat build of Keycloak and restart the server if it is already running.

When implementing custom providers in Red Hat build of Keycloak there may often be a need to add additional templates, resources and messages bundles.

The easiest way to load additional theme resources is to create a JAR with templates in theme-resources/templates resources in theme-resources/resources and messages bundles in theme-resources/messages.

If you want a more flexible way to load templates and resources that can be achieved through the ThemeResourceSPI. By implementing ThemeResourceProviderFactory and ThemeResourceProvider you can decide exactly how to load templates and resources.

By default, the locale is selected using the DefaultLocaleSelectorProvider which implements the LocaleSelectorProvider interface. English is the default language when internationalization is disabled.

With internationalization enabled, the locale is resolved according to the logic described in the Server Administration Guide.

This behavior can be changed through the LocaleSelectorSPI by implementing the LocaleSelectorProvider and LocaleSelectorProviderFactory.

The LocaleSelectorProvider interface has a single method, resolveLocale, which must return a locale given a RealmModel and a nullable UserModel. The actual request is available from the KeycloakSession#getContext method.

Custom implementations can extend the DefaultLocaleSelectorProvider in order to reuse parts of the default behavior. For example to ignore the Accept-Language request header, a custom implementation could extend the default provider, override it’s getAcceptLanguageHeaderLocale, and return a null value. As a result the locale selection will fall back on the realm’s default language.

Red Hat build of Keycloak allows you to store tokens and responses from the authentication process with the external IDP. For that, you can use the Store Token configuration option on the IDP’s settings page.

Application code can retrieve these tokens and responses to pull in extra user information, or to securely invoke requests on the external IDP. For example, an application might want to use the Google token to invoke on other Google services and REST APIs. To retrieve a token for a particular identity provider you need to send a request as follows:

GET /realms/{realm}/broker/{provider_alias}/token HTTP/1.1
Host: localhost:8080
Authorization: Bearer <KEYCLOAK ACCESS TOKEN>

An application must have authenticated with Red Hat build of Keycloak and have received an access token. This access token will need to have the broker client-level role read-token set. This means that the user must have a role mapping for this role and the client application must have that role within its scope. In this case, given that you are accessing a protected service in Red Hat build of Keycloak, you need to send the access token issued by Red Hat build of Keycloak during the user authentication. In the broker configuration page you can automatically assign this role to newly imported users by turning on the Stored Tokens Readable switch.

These external tokens can be re-established by either logging in again through the provider, or using the client initiated account linking API.

Some applications want to integrate with social providers like Facebook, but do not want to provide an option to login via these social providers. Red Hat build of Keycloak offers a browser-based API that applications can use to link an existing user account to a specific external IDP. This is called client-initiated account linking. Account linking can only be initiated by OIDC applications.

The way it works is that the application forwards the user’s browser to a URL on the Red Hat build of Keycloak server requesting that it wants to link the user’s account to a specific external provider (i.e. Facebook). The server initiates a login with the external provider. The browser logs in at the external provider and is redirected back to the server. The server establishes the link and redirects back to the application with a confirmation.

There are some preconditions that must be met by the client application before it can initiate this protocol:

To initiate the login, the application must fabricate a URL and redirect the user’s browser to this URL. The URL looks like this:

/{auth-server-root}/realms/{realm}/broker/{provider}/link?client_id={id}&redirect_uri={uri}&nonce={nonce}&hash={hash}

Here’s a description of each path and query param:

Here’s an example of Java Servlet code that generates the URL to establish the account link.

   KeycloakSecurityContext session = (KeycloakSecurityContext) httpServletRequest.getAttribute(KeycloakSecurityContext.class.getName());
   AccessToken token = session.getToken();
   String clientId = token.getIssuedFor();
   String nonce = UUID.randomUUID().toString();
   MessageDigest md = null;
   try {
      md = MessageDigest.getInstance("SHA-256");
   } catch (NoSuchAlgorithmException e) {
      throw new RuntimeException(e);
   }
   String input = nonce + token.getSessionState() + clientId + provider;
   byte[] check = md.digest(input.getBytes(StandardCharsets.UTF_8));
   String hash = Base64Url.encode(check);
   request.getSession().setAttribute("hash", hash);
   String redirectUri = ...;
   String accountLinkUrl = KeycloakUriBuilder.fromUri(authServerRootUrl)
                    .path("/realms/{realm}/broker/{provider}/link")
                    .queryParam("nonce", nonce)
                    .queryParam("hash", hash)
                    .queryParam("client_id", clientId)
                    .queryParam("redirect_uri", redirectUri).build(realm, provider).toString();

Why is this hash included? We do this so that the auth server is guaranteed to know that the client application initiated the request and no other rogue app just randomly asked for a user account to be linked to a specific provider. The auth server will first check to see if the user is logged in by checking the SSO cookie set at login. It will then try to regenerate the hash based on the current login and match it up to the hash sent by the application.

After the account has been linked, the auth server will redirect back to the redirect_uri. If there is a problem servicing the link request, the auth server may or may not redirect back to the redirect_uri. The browser may just end up at an error page instead of being redirected back to the application. If there is an error condition and the auth server deems it safe enough to redirect back to the client app, an additional error query parameter will be appended to the redirect_uri.

To implement an SPI you need to implement its ProviderFactory and Provider interfaces. You also need to create a service configuration file.

For example, to implement the Theme Selector SPI you need to implement ThemeSelectorProviderFactory and ThemeSelectorProvider and also provide the file META-INF/services/org.keycloak.theme.ThemeSelectorProviderFactory.

Example ThemeSelectorProviderFactory:

package org.acme.provider;

import ...

public class MyThemeSelectorProviderFactory implements ThemeSelectorProviderFactory {

    @Override
    public ThemeSelectorProvider create(KeycloakSession session) {
        return new MyThemeSelectorProvider(session);
    }

    @Override
    public void init(Config.Scope config) {
    }

    @Override
    public void postInit(KeycloakSessionFactory factory) {
    }

    @Override
    public void close() {
    }

    @Override
    public String getId() {
        return "myThemeSelector";
    }
}

It is recommended that your provider factory implementation returns unique id by method getId(). However there can be some exceptions to this rule as mentioned below in the Overriding providers section.

Example ThemeSelectorProvider:

package org.acme.provider;

import ...

public class MyThemeSelectorProvider implements ThemeSelectorProvider {

    public MyThemeSelectorProvider(KeycloakSession session) {
    }


    @Override
    public String getThemeName(Theme.Type type) {
        return "my-theme";
    }

    @Override
    public void close() {
    }
}

Example service configuration file (META-INF/services/org.keycloak.theme.ThemeSelectorProviderFactory):

org.acme.provider.MyThemeSelectorProviderFactory

To configure your provider, see the Configuring Providers chapter.

For example, to configure a provider you can set options as follows:

bin/kc.[sh|bat] --spi-theme-selector-my-theme-selector-enabled=true --spi-theme-selector-my-theme-selector-theme=my-theme

Then you can retrieve the config in the ProviderFactory init method:

public void init(Config.Scope config) {
    String themeName = config.get("theme");
}

Your provider can also look up other providers if needed. For example:

public class MyThemeSelectorProvider implements ThemeSelectorProvider {

    private KeycloakSession session;

    public MyThemeSelectorProvider(KeycloakSession session) {
        this.session = session;
    }

    @Override
    public String getThemeName(Theme.Type type) {
        return session.getContext().getRealm().getLoginTheme();
    }
}

public class CustomOIDCLoginProtocolFactory extends OIDCLoginProtocolFactory {

    // Some customizations here

    @Override
    public int order() {
        return 1;
    }
}

package org.acme.provider;

import ...

public class MyThemeSelectorProviderFactory implements ThemeSelectorProviderFactory, ServerInfoAwareProviderFactory {
    ...

    @Override
    public Map<String, String> getOperationalInfo() {
        Map<String, String> ret = new LinkedHashMap<>();
        ret.put("theme-name", "my-theme");
        return ret;
    }
}

In your provider implementation, you can use other providers available in Red Hat build of Keycloak. The existing providers can be typically retrieved with the usage of the KeycloakSession, which is available to your provider as described in the section Implementing an SPI.

Red Hat build of Keycloak has two provider types:

For example such as:

bin/kc.[sh|bat] build --spi-hostname-provider=default

The value default used as the value of default-provider must match the ID returned by the ProviderFactory.getId() of the particular provider factory implementation. In the code, you can obtain the provider such as keycloakSession.getProvider(HostnameProvider.class)

Providers are registered with the server by simply copying the JAR file to the providers directory.

If your provider needs additional dependencies not already provided by Keycloak copy these to the providers directory.

After registering new providers or dependencies Keycloak needs to be re-built with a non-optimized start or the kc.[sh|bat] build command.

find . -type f -name "*.jar" -exec unzip -l {} \; | grep some.file

./kc.sh -Dquarkus.launch.rebuild=true

bin/kc.[sh|bat] build --spi-user-cache-infinispan-enabled=false

Red Hat build of Keycloak has the ability to execute scripts during runtime in order to allow administrators to customize specific functionalities:

AuthenticationFlowError = Java.type("org.keycloak.authentication.AuthenticationFlowError");

function authenticate(context) {

  LOG.info(script.name + " --> trace auth for: " + user.username);

  if (   user.username === "tester"
      && user.getAttribute("someAttribute")
      && user.getAttribute("someAttribute").contains("someValue")) {

      context.failure(AuthenticationFlowError.INVALID_USER);
      return;
  }

  context.success();
}

- User-authentication-subflow REQUIRED
-- Cookie ALTERNATIVE
-- Identity-provider-redirect ALTERNATIVE
...
- Your-Script-Authenticator REQUIRED

// prints can be used to log information for debug purpose.
print("STARTING CUSTOM MAPPER");

var inputRequest = keycloakSession.getContext().getHttpRequest();
var params = inputRequest.getDecodedFormParameters();
var output = params.getFirst("user_input");
exports = output;

META-INF/keycloak-scripts.json

my-script-authenticator.js
my-script-policy.js
my-script-mapper.js

{
    "authenticators": [
        {
            "name": "My Authenticator",
            "fileName": "my-script-authenticator.js",
            "description": "My Authenticator from a JS file"
        }
    ],
    "policies": [
        {
            "name": "My Policy",
            "fileName": "my-script-policy.js",
            "description": "My Policy from a JS file"
        }
    ],
    "mappers": [
        {
            "name": "My Mapper",
            "fileName": "my-script-mapper.js",
            "description": "My Mapper from a JS file"
        }
    ],
    "saml-mappers": [
        {
            "name": "My Mapper",
            "fileName": "my-script-mapper.js",
            "description": "My Mapper from a JS file"
        }
    ]
}

If you want to see list of all available SPIs at runtime, you can check Server Info page in Admin Console as described in Admin Console section.

When building an implementation of the User Storage SPI you have to define a provider class and a provider factory. Provider class instances are created per transaction by provider factories. Provider classes do all the heavy lifting of user lookup and other user operations. They must implement the org.keycloak.storage.UserStorageProvider interface.

package org.keycloak.storage;

public interface UserStorageProvider extends Provider {


    /**
     * Callback when a realm is removed.  Implement this if, for example, you want to do some
     * cleanup in your user storage when a realm is removed
     *
     * @param realm
     */
    default
    void preRemove(RealmModel realm) {

    }

    /**
     * Callback when a group is removed.  Allows you to do things like remove a user
     * group mapping in your external store if appropriate
     *
     * @param realm
     * @param group
     */
    default
    void preRemove(RealmModel realm, GroupModel group) {

    }

    /**
     * Callback when a role is removed.  Allows you to do things like remove a user
     * role mapping in your external store if appropriate

     * @param realm
     * @param role
     */
    default
    void preRemove(RealmModel realm, RoleModel role) {

    }

}

You may be thinking that the UserStorageProvider interface is pretty sparse? You’ll see later in this chapter that there are other mix-in interfaces your provider class may implement to support the meat of user integration.

UserStorageProvider instances are created once per transaction. When the transaction is complete, the UserStorageProvider.close() method is invoked and the instance is then garbage collected. Instances are created by provider factories. Provider factories implement the org.keycloak.storage.UserStorageProviderFactory interface.

package org.keycloak.storage;

/**
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
public interface UserStorageProviderFactory<T extends UserStorageProvider> extends ComponentFactory<T, UserStorageProvider> {

    /**
     * This is the name of the provider and will be shown in the admin console as an option.
     *
     * @return
     */
    @Override
    String getId();

    /**
     * called per Keycloak transaction.
     *
     * @param session
     * @param model
     * @return
     */
    T create(KeycloakSession session, ComponentModel model);
...
}

Provider factory classes must specify the concrete provider class as a template parameter when implementing the UserStorageProviderFactory. This is a must as the runtime will introspect this class to scan for its capabilities (the other interfaces it implements). So for example, if your provider class is named FileProvider, then the factory class should look like this:

public class FileProviderFactory implements UserStorageProviderFactory<FileProvider> {

    public String getId() { return "file-provider"; }

    public FileProvider create(KeycloakSession session, ComponentModel model) {
       ...
    }

The getId() method returns the name of the User Storage provider. This id will be displayed in the admin console’s User Federation page when you want to enable the provider for a specific realm.

The create() method is responsible for allocating an instance of the provider class. It takes a org.keycloak.models.KeycloakSession parameter. This object can be used to look up other information and metadata as well as provide access to various other components within the runtime. The ComponentModel parameter represents how the provider was enabled and configured within a specific realm. It contains the instance id of the enabled provider as well as any configuration you may have specified for it when you enabled through the admin console.

The UserStorageProviderFactory has other capabilities as well which we will go over later in this chapter.

If you have examined the UserStorageProvider interface closely you might notice that it does not define any methods for locating or managing users. These methods are actually defined in other capability interfaces depending on what scope of capabilities your external user store can provide and execute on. For example, some external stores are read-only and can only do simple queries and credential validation. You will only be required to implement the capability interfaces for the features you are able to. You can implement these interfaces:

Most of the methods defined in the capability interfaces either return or are passed in representations of a user. These representations are defined by the org.keycloak.models.UserModel interface. App developers are required to implement this interface. It provides a mapping between the external user store and the user metamodel that Red Hat build of Keycloak uses.

package org.keycloak.models;

public interface UserModel extends RoleMapperModel {
    String getId();

    String getUsername();
    void setUsername(String username);

    String getFirstName();
    void setFirstName(String firstName);

    String getLastName();
    void setLastName(String lastName);

    String getEmail();
    void setEmail(String email);
...
}

UserModel implementations provide access to read and update metadata about the user including things like username, name, email, role and group mappings, as well as other arbitrary attributes.

There are other model classes within the org.keycloak.models package that represent other parts of the Red Hat build of Keycloak metamodel: RealmModel, RoleModel, GroupModel, and ClientModel.

"f:" + component id + ":" + external id

f:332a234e31234:wburke

In order for Red Hat build of Keycloak to recognize the provider, you need to add a file to the JAR: META-INF/services/org.keycloak.storage.UserStorageProviderFactory. This file must contain a line-separated list of fully qualified classnames of the UserStorageProviderFactory implementations:

org.keycloak.examples.federation.properties.ClasspathPropertiesStorageFactory
org.keycloak.examples.federation.properties.FilePropertiesStorageFactory

To deploy this jar, copy it to the providers/ directory, then run bin/kc.[sh|bat] build.

To illustrate the basics of implementing the User Storage SPI let’s walk through a simple example. In this chapter you’ll see the implementation of a simple UserStorageProvider that looks up users in a simple property file. The property file contains username and password definitions and is hardcoded to a specific location on the classpath. The provider will be able to look up the user by ID and username and also be able to validate passwords. Users that originate from this provider will be read-only.

public class PropertyFileUserStorageProvider implements
        UserStorageProvider,
        UserLookupProvider,
        CredentialInputValidator,
        CredentialInputUpdater
{
...
}

    protected KeycloakSession session;
    protected Properties properties;
    protected ComponentModel model;
    // map of loaded users in this transaction
    protected Map<String, UserModel> loadedUsers = new HashMap<>();

    public PropertyFileUserStorageProvider(KeycloakSession session, ComponentModel model, Properties properties) {
        this.session = session;
        this.model = model;
        this.properties = properties;
    }

    @Override
    public UserModel getUserByUsername(RealmModel realm, String username) {
        UserModel adapter = loadedUsers.get(username);
        if (adapter == null) {
            String password = properties.getProperty(username);
            if (password != null) {
                adapter = createAdapter(realm, username);
                loadedUsers.put(username, adapter);
            }
        }
        return adapter;
    }

    protected UserModel createAdapter(RealmModel realm, String username) {
        return new AbstractUserAdapter(session, realm, model) {
            @Override
            public String getUsername() {
                return username;
            }
        };
    }

    @Override
    public UserModel getUserById(RealmModel realm, String id) {
        StorageId storageId = new StorageId(id);
        String username = storageId.getExternalId();
        return getUserByUsername(realm, username);
    }

    @Override
    public UserModel getUserByEmail(RealmModel realm, String email) {
        return null;
    }

"f:" + component id + ":" + username

    @Override
    public boolean isConfiguredFor(RealmModel realm, UserModel user, String credentialType) {
        String password = properties.getProperty(user.getUsername());
        return credentialType.equals(PasswordCredentialModel.TYPE) && password != null;
    }

    @Override
    public boolean supportsCredentialType(String credentialType) {
        return credentialType.equals(PasswordCredentialModel.TYPE);
    }

    @Override
    public boolean isValid(RealmModel realm, UserModel user, CredentialInput input) {
        if (!supportsCredentialType(input.getType())) return false;

        String password = properties.getProperty(user.getUsername());
        if (password == null) return false;
        return password.equals(input.getChallengeResponse());
    }

    @Override
    public boolean updateCredential(RealmModel realm, UserModel user, CredentialInput input) {
        if (input.getType().equals(PasswordCredentialModel.TYPE)) throw new ReadOnlyException("user is read only for this update");

        return false;
    }

    @Override
    public void disableCredentialType(RealmModel realm, UserModel user, String credentialType) {

    }

    @Override
    public Stream<String> getDisableableCredentialTypesStream(RealmModel realm, UserModel user) {
        return Stream.empty();
    }

public class PropertyFileUserStorageProviderFactory
                 implements UserStorageProviderFactory<PropertyFileUserStorageProvider> {

    public static final String PROVIDER_NAME = "readonly-property-file";

    @Override
    public String getId() {
        return PROVIDER_NAME;
    }

    private static final Logger logger = Logger.getLogger(PropertyFileUserStorageProviderFactory.class);
    protected Properties properties = new Properties();

    @Override
    public void init(Config.Scope config) {
        InputStream is = getClass().getClassLoader().getResourceAsStream("/users.properties");

        if (is == null) {
            logger.warn("Could not find users.properties in classpath");
        } else {
            try {
                properties.load(is);
            } catch (IOException ex) {
                logger.error("Failed to load users.properties file", ex);
            }
        }
    }

    @Override
    public PropertyFileUserStorageProvider create(KeycloakSession session, ComponentModel model) {
        return new PropertyFileUserStorageProvider(session, model, properties);
    }

kc.[sh|bat] start --spi-storage-readonly-property-file-path=/other-users.properties

public void init(Config.Scope config) {
    String path = config.get("path");
    InputStream is = getClass().getClassLoader().getResourceAsStream(path);

    ...
}

    @Override
    public PropertyFileUserStorageProvider create(KeycloakSession session, ComponentModel model) {
        return new PropertyFileUserStorageProvider(session, model, properties);
    }

org.keycloak.examples.federation.properties.FilePropertiesStorageFactory

Our PropertyFileUserStorageProvider example is a bit contrived. It is hardcoded to a property file that is embedded in the jar of the provider, which is not terribly useful. We might want to make the location of this file configurable per instance of the provider. In other words, we might want to reuse this provider multiple times in multiple different realms and point to completely different user property files. We’ll also want to perform this configuration within the Admin Console UI.

The UserStorageProviderFactory has additional methods you can implement that handle provider configuration. You describe the variables you want to configure per provider and the Admin Console automatically renders a generic input page to gather this configuration. When implemented, callback methods also validate the configuration before it is saved, when a provider is created for the first time, and when it is updated. UserStorageProviderFactory inherits these methods from the org.keycloak.component.ComponentFactory interface.

    List<ProviderConfigProperty> getConfigProperties();

    default
    void validateConfiguration(KeycloakSession session, RealmModel realm, ComponentModel model)
            throws ComponentValidationException
    {

    }

    default
    void onCreate(KeycloakSession session, RealmModel realm, ComponentModel model) {

    }

    default
    void onUpdate(KeycloakSession session, RealmModel realm, ComponentModel model) {

    }

The ComponentFactory.getConfigProperties() method returns a list of org.keycloak.provider.ProviderConfigProperty instances. These instances declare metadata that is needed to render and store each configuration variable of the provider.

public class PropertyFileUserStorageProviderFactory
                  implements UserStorageProviderFactory<PropertyFileUserStorageProvider> {

    protected static final List<ProviderConfigProperty> configMetadata;

    static {
        configMetadata = ProviderConfigurationBuilder.create()
                .property().name("path")
                .type(ProviderConfigProperty.STRING_TYPE)
                .label("Path")
                .defaultValue("${jboss.server.config.dir}/example-users.properties")
                .helpText("File path to properties file")
                .add().build();
    }

    @Override
    public List<ProviderConfigProperty> getConfigProperties() {
        return configMetadata;
    }

    @Override
    public void validateConfiguration(KeycloakSession session, RealmModel realm, ComponentModel config)
                   throws ComponentValidationException {
        String fp = config.getConfig().getFirst("path");
        if (fp == null) throw new ComponentValidationException("user property file does not exist");
        fp = EnvUtil.replace(fp);
        File file = new File(fp);
        if (!file.exists()) {
            throw new ComponentValidationException("user property file does not exist");
        }
    }

    @Override
    public PropertyFileUserStorageProvider create(KeycloakSession session, ComponentModel model) {
        String path = model.getConfig().getFirst("path");

        Properties props = new Properties();
        try {
            InputStream is = new FileInputStream(path);
            props.load(is);
            is.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }

        return new PropertyFileUserStorageProvider(session, model, props);
    }

One thing we have not done with our example is allow it to add and remove users or change passwords. Users defined in our example are also not queryable or viewable in the Admin Console. To add these enhancements, our example provider must implement the UserQueryMethodsProvider (or UserQueryProvider) and UserRegistrationProvider interfaces.

    public void save() {
        String path = model.getConfig().getFirst("path");
        path = EnvUtil.replace(path);
        try {
            FileOutputStream fos = new FileOutputStream(path);
            properties.store(fos, "");
            fos.close();
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static final String UNSET_PASSWORD="#$!-UNSET-PASSWORD";

    @Override
    public UserModel addUser(RealmModel realm, String username) {
        synchronized (properties) {
            properties.setProperty(username, UNSET_PASSWORD);
            save();
        }
        return createAdapter(realm, username);
    }

    @Override
    public boolean removeUser(RealmModel realm, UserModel user) {
        synchronized (properties) {
            if (properties.remove(user.getUsername()) == null) return false;
            save();
            return true;
        }
    }

    @Override
    public boolean isValid(RealmModel realm, UserModel user, CredentialInput input) {
        if (!supportsCredentialType(input.getType()) || !(input instanceof UserCredentialModel)) return false;

        UserCredentialModel cred = (UserCredentialModel)input;
        String password = properties.getProperty(user.getUsername());
        if (password == null || UNSET_PASSWORD.equals(password)) return false;
        return password.equals(cred.getValue());
    }

    @Override
    public boolean updateCredential(RealmModel realm, UserModel user, CredentialInput input) {
        if (!(input instanceof UserCredentialModel)) return false;
        if (!input.getType().equals(PasswordCredentialModel.TYPE)) return false;
        UserCredentialModel cred = (UserCredentialModel)input;
        synchronized (properties) {
            properties.setProperty(user.getUsername(), cred.getValue());
            save();
        }
        return true;
    }

    @Override
    public void disableCredentialType(RealmModel realm, UserModel user, String credentialType) {
        if (!credentialType.equals(PasswordCredentialModel.TYPE)) return;
        synchronized (properties) {
            properties.setProperty(user.getUsername(), UNSET_PASSWORD);
            save();
        }

    }

    private static final Set<String> disableableTypes = new HashSet<>();

    static {
        disableableTypes.add(PasswordCredentialModel.TYPE);
    }

    @Override
    public Stream<String> getDisableableCredentialTypes(RealmModel realm, UserModel user) {

        return disableableTypes.stream();
    }

    @Override
    public int getUsersCount(RealmModel realm) {
        return properties.size();
    }

    @Override
    public Stream<UserModel> searchForUserStream(RealmModel realm, String search, Integer firstResult, Integer maxResults) {
        Predicate<String> predicate = "*".equals(search) ? username -> true : username -> username.contains(search);
        return properties.keySet().stream()
                .map(String.class::cast)
                .filter(predicate)
                .skip(firstResult)
                .map(username -> getUserByUsername(realm, username))
                .limit(maxResults);
    }

    @Override
    public Stream<UserModel> searchForUserStream(RealmModel realm, Map<String, String> params, Integer firstResult, Integer maxResults) {
        // only support searching by username
        String usernameSearchString = params.get("username");
        if (usernameSearchString != null)
            return searchForUserStream(realm, usernameSearchString, firstResult, maxResults);

        // if we are not searching by username, return all users
        return searchForUserStream(realm, "*", firstResult, maxResults);
    }

    @Override
    public Stream<UserModel> getGroupMembersStream(RealmModel realm, GroupModel group, Integer firstResult, Integer maxResults) {
        return Stream.empty();
    }

    @Override
    public Stream<UserModel> searchForUserByUserAttributeStream(RealmModel realm, String attrName, String attrValue) {
        return Stream.empty();
    }

The PropertyFileUserStorageProvider example is really limited. While we will be able to log in with users stored in a property file, we won’t be able to do much else. If users loaded by this provider need special role or group mappings to fully access particular applications there is no way for us to add additional role mappings to these users. You also can’t modify or add additional important attributes like email, first and last name.

For these types of situations, Red Hat build of Keycloak allows you to augment your external store by storing extra information in Red Hat build of Keycloak’s database. This is called federated user storage and is encapsulated within the org.keycloak.storage.federated.UserFederatedStorageProvider class.

package org.keycloak.storage.federated;

public interface UserFederatedStorageProvider extends Provider,
        UserAttributeFederatedStorage,
        UserBrokerLinkFederatedStorage,
        UserConsentFederatedStorage,
        UserNotBeforeFederatedStorage,
        UserGroupMembershipFederatedStorage,
        UserRequiredActionsFederatedStorage,
        UserRoleMappingsFederatedStorage,
        UserFederatedUserCredentialStore {
    ...

}

The UserFederatedStorageProvider instance is available on the UserStorageUtil.userFederatedStorage(KeycloakSession) method. It has all different kinds of methods for storing attributes, group and role mappings, different credential types, and required actions. If your external store’s datamodel cannot support the full Red Hat build of Keycloak feature set, then this service can fill in the gaps.

Red Hat build of Keycloak comes with a helper class org.keycloak.storage.adapter.AbstractUserAdapterFederatedStorage that will delegate every single UserModel method except get/set of username to user federated storage. Override the methods you need to override to delegate to your external storage representations. It is strongly suggested you read the javadoc of this class as it has smaller protected methods you may want to override. Specifically surrounding group membership and role mappings.

    protected UserModel createAdapter(RealmModel realm, String username) {
        return new AbstractUserAdapterFederatedStorage(session, realm, model) {
            @Override
            public String getUsername() {
                return username;
            }

            @Override
            public void setUsername(String username) {
                String pw = (String)properties.remove(username);
                if (pw != null) {
                    properties.put(username, pw);
                    save();
                }
            }
        };
    }

When implementing a user storage provider, there’s another strategy you can take. Instead of using user federated storage, you can create a user locally in the Red Hat build of Keycloak built-in user database and copy attributes from your external store into this local copy. There are many advantages to this approach.

There are some obvious disadvantages though to using an import strategy:

To implement the import strategy you simply check to see first if the user has been imported locally. If so return the local user, if not create the user locally and import data from the external store. You can also proxy the local user so that most changes are automatically synchronized.

This will be a bit contrived, but we can extend our PropertyFileUserStorageProvider to take this approach. We begin first by modifying the createAdapter() method.

    protected UserModel createAdapter(RealmModel realm, String username) {
        UserModel local = UserStoragePrivateUtil.userLocalStorage(session).getUserByUsername(realm, username);
        if (local == null) {
            local = UserStoragePrivateUtil.userLocalStorage(session).addUser(realm, username);
            local.setFederationLink(model.getId());
        }
        return new UserModelDelegate(local) {
            @Override
            public void setUsername(String username) {
                String pw = (String)properties.remove(username);
                if (pw != null) {
                    properties.put(username, pw);
                    save();
                }
                super.setUsername(username);
            }
        };
    }

In this method we call the UserStoragePrivateUtil.userLocalStorage(session) method to obtain a reference to local Red Hat build of Keycloak user storage. We see if the user is stored locally, if not, we add it locally. Do not set the id of the local user. Let Red Hat build of Keycloak automatically generate the id. Also note that we call UserModel.setFederationLink() and pass in the ID of the ComponentModel of our provider. This sets a link between the provider and the imported user.

Another thing to note is that if a local user is linked, your storage provider will still be delegated to for methods that it implements from the CredentialInputValidator and CredentialInputUpdater interfaces. Returning false from a validation or update will just result in Red Hat build of Keycloak seeing if it can validate or update using local storage.

Also notice that we are proxying the local user using the org.keycloak.models.utils.UserModelDelegate class. This class is an implementation of UserModel. Every method just delegates to the UserModel it was instantiated with. We override the setUsername() method of this delegate class to synchronize automatically with the property file. For your providers, you can use this to intercept other methods on the local UserModel to perform synchronization with your external store. For example, get methods could make sure that the local store is in sync. Set methods keep the external store in sync with the local one. One thing to note is that the getId() method should always return the id that was auto generated when you created the user locally. You should not return a federated id as shown in the other non-import examples.

package org.keycloak.storage.user;
public interface ImportedUserValidation {
    /**
     * If this method returns null, then the user in local storage will be removed
     *
     * @param realm
     * @param user
     * @return null if user no longer valid
     */
    UserModel validate(RealmModel realm, UserModel user);
}

package org.keycloak.storage.user;

public interface ImportSynchronization {
    SynchronizationResult sync(KeycloakSessionFactory sessionFactory, String realmId, UserStorageProviderModel model);
    SynchronizationResult syncSince(Date lastSync, KeycloakSessionFactory sessionFactory, String realmId, UserStorageProviderModel model);
}

When a user object is loaded by ID, username, or email queries it is cached. When a user object is being cached, it iterates through the entire UserModel interface and pulls this information to a local in-memory-only cache. In a cluster, this cache is still local, but it becomes an invalidation cache. When a user object is modified, it is evicted. This eviction event is propagated to the entire cluster so that the other nodes' user cache is also invalidated.

/**
 * All these methods effect an entire cluster of Keycloak instances.
 *
 * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
 * @version $Revision: 1 $
 */
public interface UserCache extends UserProvider {
    /**
     * Evict user from cache.
     *
     * @param user
     */
    void evict(RealmModel realm, UserModel user);

    /**
     * Evict users of a specific realm
     *
     * @param realm
     */
    void evict(RealmModel realm);

    /**
     * Clear cache entirely.
     *
     */
    void clear();
}

public interface OnUserCache {
    void onCache(RealmModel realm, CachedUserModel user, UserModel delegate);
}

public interface CachedUserModel extends UserModel {

    /**
     * Invalidates the cache for this user and returns a delegate that represents the actual data provider
     *
     * @return
     */
    UserModel getDelegateForUpdate();

    boolean isMarkedForEviction();

    /**
     * Invalidate the cache for this model
     *
     */
    void invalidate();

    /**
     * When was the model was loaded from database.
     *
     * @return
     */
    long getCacheTimestamp();

    /**
     * Returns a map that contains custom things that are cached along with this model.  You can write to this map.
     *
     * @return
     */
    ConcurrentHashMap getCachedWith();
}

Since version 20, Keycloak relies only on Quarkus. Unlike WildFly, Quarkus is not an Application Server. For more detail, see https://www.keycloak.org/migration/migrating-to-quarkus#_quarkus_is_not_an_application_server.

Therefore, the User Storage Providers cannot be packaged within any Jakarta EE component or make it an EJB as was the case when Keycloak ran over WildFly in previous versions.

Providers implementations are required to be plain java objects which implement the suitable User Storage SPI interfaces, as was explained in the previous sections. And they must be packaged and deployed as stated in this Migration Guide:

You can still implement your custom UserStorageProvider class, which is able to integrate an external database by JPA Entity Manager, as shown in this example:

CDI is not supported.

You can create, remove, and update your user storage provider deployments through the administrator REST API. The User Storage SPI is built on top of a generic component interface so you will be using that generic API to manage your providers.

The REST Component API lives under your realm admin resource.

/admin/realms/{realm-name}/components

We will only show this REST API interaction with the Java client. Hopefully you can extract how to do this from curl from this API.

public interface ComponentsResource {
    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<ComponentRepresentation> query();

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<ComponentRepresentation> query(@QueryParam("parent") String parent);

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<ComponentRepresentation> query(@QueryParam("parent") String parent, @QueryParam("type") String type);

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<ComponentRepresentation> query(@QueryParam("parent") String parent,
                                               @QueryParam("type") String type,
                                               @QueryParam("name") String name);

    @POST
    @Consumes(MediaType.APPLICATION_JSON)
    Response add(ComponentRepresentation rep);

    @Path("{id}")
    ComponentResource component(@PathParam("id") String id);
}

public interface ComponentResource {
    @GET
    public ComponentRepresentation toRepresentation();

    @PUT
    @Consumes(MediaType.APPLICATION_JSON)
    public void update(ComponentRepresentation rep);

    @DELETE
    public void remove();
}

To create a user storage provider, you must specify the provider id, a provider type of the string org.keycloak.storage.UserStorageProvider, as well as the configuration.

import org.keycloak.admin.client.Keycloak;
import org.keycloak.representations.idm.RealmRepresentation;
...

Keycloak keycloak = Keycloak.getInstance(
    "http://localhost:8080",
    "master",
    "admin",
    "password",
    "admin-cli");
RealmResource realmResource = keycloak.realm("master");
RealmRepresentation realm = realmResource.toRepresentation();

ComponentRepresentation component = new ComponentRepresentation();
component.setName("home");
component.setProviderId("readonly-property-file");
component.setProviderType("org.keycloak.storage.UserStorageProvider");
component.setParentId(realm.getId());
component.setConfig(new MultivaluedHashMap());
component.getConfig().putSingle("path", "~/users.properties");

realmResource.components().add(component);

// retrieve a component

List<ComponentRepresentation> components = realmResource.components().query(realm.getId(),
                                                                    "org.keycloak.storage.UserStorageProvider",
                                                                    "home");
component = components.get(0);

// Update a component

component.getConfig().putSingle("path", "~/my-users.properties");
realmResource.components().component(component.getId()).update(component);

// Remove a component

realmREsource.components().component(component.getId()).remove();

In Keycloak version 2.4.0 and earlier there was a User Federation SPI. Red Hat Single Sign-On version 7.0, although unsupported, had this earlier SPI available as well. This earlier User Federation SPI has been removed from Keycloak version 2.5.0 and Red Hat Single Sign-On version 7.1. However, if you have written a provider with this earlier SPI, this chapter discusses some strategies you can use to port it.

Many of the user storage interfaces in Red Hat build of Keycloak contain query methods that can return potentially large sets of objects, which might lead to significant impacts in terms of memory consumption and processing time. This is especially true when only a small subset of the objects' internal state is used in the query method’s logic.

To provide developers with a more efficient alternative to process large data sets in these query methods, a Streams sub-interface has been added to user storage interfaces. These Streams sub-interfaces replace the original collection-based methods in the super-interfaces with stream-based variants, making the collection-based methods default. The default implementation of a collection-based query method invokes its Stream counterpart and collects the result into the proper collection type.

The Streams sub-interfaces allow for implementations to focus on the stream-based approach for processing sets of data and benefit from the potential memory and performance optimizations of that approach. The interfaces that offer a Streams sub-interface to be implemented include a few capability interfaces, all interfaces in the org.keycloak.storage.federated package and a few others that might be implemented depending on the scope of the custom storage implementation.

See this list of the interfaces that offer a Streams sub-interface to developers.

(*) indicates the interface is a capability interface

Custom user storage implementation that want to benefit from the streams approach should simply implement the Streams sub-interfaces instead of the original interfaces. For example, the following code uses the Streams variant of the UserQueryProvider interface:

public class CustomQueryProvider extends UserQueryProvider.Streams {
...
    @Override
    Stream<UserModel> getUsersStream(RealmModel realm, Integer firstResult, Integer maxResults) {
        // custom logic here
    }

    @Override
    Stream<UserModel> searchForUserStream(String search, RealmModel realm) {
        // custom logic here
    }
...
}

You can use a vault SPI from org.keycloak.vault package to write custom extension for Red Hat build of Keycloak to connect to arbitrary vault implementation.

The built-in files-plaintext provider is an example of the implementation of this SPI. In general the following rules apply:

For details on how to package and deploy a custom provider refer to the Service Provider Interfaces chapter.

The vault contains sensitive data and Red Hat build of Keycloak treats the secrets accordingly. When accessing a secret, the secret is obtained from the vault and retained in JVM memory only for the necessary time. Then all possible attempts to discard its content from JVM memory is done. This is achieved by using the vault secrets only within try-with-resources statement as outlined below:

    char[] c;
    try (VaultCharSecret cSecret = session.vault().getCharSecret(SECRET_NAME)) {
        // ... use cSecret
        c = cSecret.getAsArray().orElse(null);
        // if c != null, it now contains password
    }

    // if c != null, it now contains garbage

The example uses KeycloakSession.vault() as the entrypoint for accessing the secrets. Using the VaultProvider.obtainSecret method directly is indeed also possible. However the vault() method has the benefit of ability to interpret the raw secret (which is generally a byte array) as a character array (via vault().getCharSecret()) or a String (via vault().getStringSecret()) in addition to obtaining the original uninterpreted value (via vault().getRawSecret() method).

Note that since String objects are immutable, their content cannot be discarded by overriding with random garbage. Even though measures have been taken in the default VaultStringSecret implementation to prevent internalizing Strings, the secrets stored in String objects would live at least to the next GC round. Thus using plain byte and character arrays and buffers is preferable.