Chapter 6. Service Provider Interfaces (SPI)

Red Hat Single Sign-On is designed to cover most use-cases without requiring custom code, but we also want it to be customizable. To achieve this Red Hat Single Sign-On has a number of Service Provider Interfaces (SPI) for which you can implement your own providers.

6.1. Implementing an SPI

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";
        }
}
Note

Keycloak creates a single instance of provider factories which makes it possible to store state for multiple requests. Provider instances are created by calling create on the factory for each request so these should be light-weight object.

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

You can configure your provider through standalone.xml, standalone-ha.xml, or domain.xml. See the Server Installation and Configuration Guide for more details on where to find these files.

For example by adding the following to standalone.xml: 

<spi name="themeSelector">
    <provider name="myThemeSelector" enabled="true">
        <properties>
            <property name="theme" value="my-theme"/>
        </properties>
    </provider>
</spi>

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 lookup other providers if needed. For example: 

public class MyThemeSelectorProvider implements EventListenerProvider {

    private KeycloakSession session;

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

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

6.1.1. Show info from your SPI implementation in admin console

Sometimes it is useful to show additional info about your Provider to a Red Hat Single Sign-On administrator. You can show provider build time information (eg. version of custom provider currently installed), current configuration of the provider (eg. url of remote system your provider talks to) or some operational info (average time of response from remote system your provider talks to). Red Hat Single Sign-On admin console provides Server Info page to show this kind of information.

To show info from your provider it is enough to implement org.keycloak.provider.ServerInfoAwareProviderFactory interface in your ProviderFactory.

Example implementation for MyThemeSelectorProviderFactory from previous example: 

package org.acme.provider;

import ...

public class MyThemeSelectorProvider implements ThemeSelectorProvider, ServerInfoAwareProviderFactory {
    ...

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

6.2. Registering provider implementations

There are two ways to register provider implementations. In most cases the simplest way is to use the Red Hat Single Sign-On deployer approach as this handles a number of dependencies automatically for you. It also supports hot deployment as well as re-deployment.

The alternative approach is to deploy as a module.

If you are creating a custom SPI you will need to deploy it as a module, otherwise we recommend using the Red Hat Single Sign-On deployer approach.

6.2.1. Using the Red Hat Single Sign-On Deployer

If you copy your provider jar to the Red Hat Single Sign-On standalone/deployments/ directory, your provider will automatically be deployed. Hot deployment works too. Additionally, your provider jar works similarly to other components deployed in a JBoss EAP environment in that they can use facilities like the jboss-deployment-structure.xml file. This file allows you to set up dependencies on other components and load third-party jars and modules.

Provider jars can also be contained within other deployable units like EARs and WARs. Deploying with a EAR actually makes it really easy to use third party jars as you can just put these libraries in the EAR’s lib/ directory.

6.2.2. Register a provider using Modules

To register a provider using Modules first create a module. To do this you can either use the jboss-cli script or manually create a folder inside KEYCLOAK_HOME/modules and add your jar and a module.xml. For example to add the event listener sysout example provider using the jboss-cli script execute: 

KEYCLOAK_HOME/bin/jboss-cli.sh --command="module add --name=org.acme.provider --resources=target/provider.jar --dependencies=org.keycloak.keycloak-core,org.keycloak.keycloak-server-spi"

Or to manually create it start by creating the folder KEYCLOAK_HOME/modules/org/acme/provider/main. Then copy provider.jar to this folder and create module.xml with the following content: 

<?xml version="1.0" encoding="UTF-8"?>
<module xmlns="urn:jboss:module:1.3" name="org.acme.provider">
    <resources>
        <resource-root path="provider.jar"/>
    </resources>
    <dependencies>
        <module name="org.keycloak.keycloak-core"/>
        <module name="org.keycloak.keycloak-server-spi"/>
    </dependencies>
</module>

Once you’ve created the module you need to register this module with Red Hat Single Sign-On. This is done by editing the keycloak-server subsystem section of standalone.xml, standalone-ha.xml, or domain.xml, and adding it to the providers: 

<subsystem xmlns="urn:jboss:domain:keycloak-server:1.1">
    <web-context>auth</web-context>
    <providers>
        <provider>module:org.keycloak.examples.event-sysout</provider>
    </providers>
    ...

6.2.3. Disabling a provider

You can disable a provider by setting the enabled attribute for the provider to false in standalone.xml, standalone-ha.xml, or domain.xml. For example to disable the Infinispan user cache provider add: 

<spi name="userCache">
    <provider name="infinispan" enabled="false"/>
</spi>

6.3. Leveraging Java EE

The service providers can be packaged within any Java EE component so long as you set up the META-INF/services file correctly to point to your providers. For example, if your provider needs to use third party libraries, you can package up your provider within an ear and store these third pary libraries in the ear’s lib/ directory. Also note that provider jars can make use of the jboss-deployment-structure.xml file that EJBs, WARS, and EARs can use in a JBoss EAP environment. See the JBoss EAP documentation for more details on this file. It allows you to pull in external dependencies among other fine grain actions.

ProviderFactory implementations are required to be plain java objects. But, we also currently support implementing provider classes as Stateful EJBs. This is how you would do it: 

@Stateful
@Local(EjbExampleUserStorageProvider.class)
public class EjbExampleUserStorageProvider implements UserStorageProvider,
        UserLookupProvider,
        UserRegistrationProvider,
        UserQueryProvider,
        CredentialInputUpdater,
        CredentialInputValidator,
        OnUserCache
{
    @PersistenceContext
    protected EntityManager em;

    protected ComponentModel model;
    protected KeycloakSession session;

    public void setModel(ComponentModel model) {
        this.model = model;
    }

    public void setSession(KeycloakSession session) {
        this.session = session;
    }


    @Remove
    @Override
    public void close() {
    }
...
}

You have to define the @Local annotation and specify your provider class there. If you don’t do this, EJB will not proxy the provider instance correctly and your provider won’t work.

You must put the @Remove annotation on the close() method of your provider. If you don’t, the stateful bean will never be cleaned up and you may eventually see error messages.

Implementations of ProviderFactory are required to be plain java objects. Your factory class would perform a JNDI lookup of the Stateful EJB in its create() method. 

public class EjbExampleUserStorageProviderFactory
        implements UserStorageProviderFactory<EjbExampleUserStorageProvider> {

    @Override
    public EjbExampleUserStorageProvider create(KeycloakSession session, ComponentModel model) {
        try {
            InitialContext ctx = new InitialContext();
            EjbExampleUserStorageProvider provider = (EjbExampleUserStorageProvider)ctx.lookup(
                     "java:global/user-storage-jpa-example/" + EjbExampleUserStorageProvider.class.getSimpleName());
            provider.setModel(model);
            provider.setSession(session);
            return provider;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

6.4. JavaScript Providers

Red Hat Single Sign-On has the ability to execute scripts during runtime in order to allow administrators to customize specific functionalities:

  • OpenID Connect Script Protocol Mapper
  • OpenID Connect Script Authenticator
  • JavaScript Policy

6.4.1. Create a JAR with the scripts you want to deploy

Note

JAR files are regular ZIP files with a .jar extension.

In order to make your scripts available to Red Hat Single Sign-On you need to deploy them to the server. For that, you should create a JAR file with the following structure: 

META-INF/keycloak-scripts.json

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

The META-INF/keycloak-scripts.json is a file descriptor that provides metadata information about the scripts you want to deploy. It is a JSON file with the following structure: 

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

This file should reference the different types of script providers that you want to deploy:

  • authenticators

    For OpenID Connect Script Authenticators. You can have one or multiple authenticators in the same JAR file

  • policies

    For JavaScript Policies when using Red Hat Single Sign-On Authorization Services. You can have one or multiple policies in the same JAR file

  • mappers

    For OpenID Connect Script Protocol Mappers. You can have one or multiple mappers in the same JAR file

For each script file in your JAR file you must have a corresponding entry in META-INF/keycloak-scripts.json that maps your scripts files to a specific provider type. For that you should provide the following properties for each entry:

  • name

    A friendly name that will be used to show the scripts through the Red Hat Single Sign-On Administration Console. If not provided, the name of the script file will be used instead

  • description

    An optional text that better describes the intend of the script file

  • fileName

    The name of the script file. This property is mandatory and should map to a file within the JAR.

6.4.2. Deploy the Script JAR

Once you have a JAR file with a descriptor and the scripts you want to deploy, you just need to copy the JAR to the to the Red Hat Single Sign-On standalone/deployments/ directory.

6.4.3. Using Red Hat Single Sign-On Administration Console to upload scripts

By default, the Red Hat Single Sign-On Administration Console won’t allow administrators to upload scripts to the server. The reason is that script execution can potentially harm the system due to the execution of malicious scripts. In order to prevent different types of attacks and lower the risks when running scripts at runtime, administrators should prefer deploying scripts directly to the server using a JAR file.

By deploying scripts directly into the server, we expect that scripts go through a proper code analysis in order to find possible vulnerabilities that can be introduced by any script deployed to the server.

However, it should still be possible to upload scripts to the server through the Red Hat Single Sign-On Administration Console. For that, you must set the following system property when booting the server: 

    -Dkeycloak.profile.feature.upload_scripts=enabled

For more details about how to enable the upload_scripts feature. Please, take a look at the Profiles.

6.5. Available SPIs

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.