<chapter id="providers">
    <title>Providers and SPIs</title>

    <para>
        Keycloak is designed to cover most use-cases without requiring custom code, but we also want it to be
        customizable. To achive this Keycloak has a number of SPIs which you can implement your own providers for.
    </para>

    <section>
        <title>Implementing a SPI</title>
        <para>
            To implement an SPI you need to implement it's ProviderFactory and Provider interfaces. You also need to
            create a provider-configuration file. For example to implement the Event Listener SPI you need to implement
            EventListenerProviderFactory and EventListenerProvider and also provide the file
            <literal>META-INF/services/org.keycloak.events.EventListenerProviderFactory</literal>
        </para>
        <para>
            For example to implement the Event Listener SPI you start by implementing EventListenerProviderFactory:
<programlisting><![CDATA[{
package org.acme.provider;

import ...

public class MyEventListenerProviderFactory implements EventListenerProviderFactory {

    private List<Event> events;

    public String getId() {
        return "my-event-listener";
    }

    public void init(Config.Scope config) {
        int max = config.getInt("max");
        events = new MaxList(max);
    }

    public EventListenerProvider create(KeycloakSession session) {
        return new MyEventListenerProvider(events);
    }

    public void close() {
        events = null;
    }

}
}]]></programlisting>
            The example uses a MaxList which has a maximum size and is concurrency safe. When the maximum size is reached
            and new entries are added the oldest entry is removed. Keycloak creates a single instance of
            EventListenerProviderFactory which makes it possible to store state for multiple requests. EventListenerProvider
            instances are created by calling create on the factory for each requests so these should be light-weight.
        </para>
        <para>
            Next you would implement EventListenerProvider:
<programlisting><![CDATA[{
package org.acme.provider;

import ...

public class MyEventListenerProvider implements EventListenerProvider {

    private List<Event> events;

    public MyEventListenerProvider(List<Event> events) {
        this.events = events;
    }

    @Override
    public void onEvent(Event event) {
        events.add(event);
    }

    @Override
    public void close() {

    }

}
}]]></programlisting>
        </para>
        <para>
            The file <literal>META-INF/services/org.keycloak.events.EventListenerProviderFactory</literal> should
            contain the full name of your ProviderFactory implementation:
<programlisting><![CDATA[org.acme.provider.MyEventListenerProviderFactory]]></programlisting>
        </para>
    </section>

    <section>
        <title>Registering provider implementations</title>
        <para>
            Keycloak loads provider implementations from the file-system. By default all JARs inside
            <literal>standalone/configuration/providers</literal> are loaded. This is simple, but requires all providers
            to share the same library. All provides also inherit all classes from the Keycloak class-loader. In the future
            we'll add support to load providers from modules, which allows better control of class isolation.
        </para>
        <para>
            To register your provider simply copy the JAR including the ProviderFactory and Provider classes and the
            provider configuration file to <literal>standalone/configuration/providers</literal>.
        </para>
        <para>
            You can also define multiple provider class-path if you want to create isolated class-loaders. To do this
            edit keycloak-server.json and add more classpath entries to the providers array. For example:
<programlisting><![CDATA[{
    "providers": [
        "classpath:provider1.jar;lib-v1.jar",
        "classpath:provider2.jar;lib-v2.jar"
    ]
}]]></programlisting>
            The above example will create two separate class-loaders for providers. The classpath entries follow the
            same syntax as Java classpath, with ';' separating multiple-entries. Wildcard is also supported allowing
            loading all jars (files with .jar or .JAR extension) in a folder, for example:
<programlisting><![CDATA[{
    "providers": [
        "classpath:/home/user/providers/*"
    ]
}]]></programlisting>
        </para>
    </section>

    <section>
        <title>Available SPIs</title>
        <para>
            Here's a list of the available SPIs and a brief description. For more details on each SPI refer to
            individual
            sections.
            <variablelist>
                <varlistentry>
                    <term>Account</term>
                    <listitem>
                        Provides the account manage console pages. The default implementation uses FreeMarker templates.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Connections Infinispan</term>
                    <listitem>
                        Loads and configures Infinispan connections. The default implementation can load connections
                        from
                        the Infinispan subsystem, or alternatively can be manually configured in keycloak-server.json.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Connections Jpa</term>
                    <listitem>
                        Loads and configures Jpa connections. The default implementation can load datasources
                        from
                        WildFly/EAP, or alternatively can be manually configured in keycloak-server.json.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Connections Jpa Updater</term>
                    <listitem>
                        Updates database schema. The default implementation uses Liquibase.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Connections Mongo</term>
                    <listitem>
                        Loads and configures MongoDB connections. The default implementation is configured in
                        keycloak-server.json.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Email</term>
                    <listitem>
                        Formats and sends email. The default implementation uses FreeMarker templates and JavaMail.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Events Listener</term>
                    <listitem>
                        Listen to user related events for example user login success and failures. Keycloak provides two
                        implementations out of box. One that logs events to the server log and another that can send
                        email
                        notifications to users on certain events.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Events Store</term>
                    <listitem>
                        Store user related events so they can be viewed through the admin console and account management
                        console.
                        Keycloak provides implementations for Relational Databases and MongoDB.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Export</term>
                    <listitem>
                        Exports the Keycloak database. Keycloak provides implementations that export to JSON files
                        either
                        as a single file, multiple files in a directory or a encrypted ZIP archive.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Import</term>
                    <listitem>
                        Imports an exported Keycloak database. Keycloak provides implementations that import from JSON
                        files either
                        as a single file, multiple files in a directory or a encrypted ZIP archive.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Login</term>
                    <listitem>
                        Provides the login pages. The default implementation uses FreeMarker templates.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Login Protocol</term>
                    <listitem>
                        Provides protocols. Keycloak provides implementations of OpenID Connect and SAML 2.0.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Realm</term>
                    <listitem>
                        Provides realm and application meta-data. Keycloak provides implementations for Relational
                        Databases
                        and MongoDB.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Realm Cache</term>
                    <listitem>
                        Caches realm and application meta-data to improve performance. Keycloak provides a basic
                        in-memory
                        cache and a Infinispan cache.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Theme</term>
                    <listitem>
                        Allows creating themes to customize look and feel. Keycloak provides implementations that can
                        load
                        themes from the file-system or classpath.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>Timer</term>
                    <listitem>
                        Executes scheduled tasks. Keycloak provides a basic implementation based on java.util.Timer.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>User</term>
                    <listitem>
                        Provides users and role-mappings. Keycloak provides implementations for Relational Databases
                        and MongoDB.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>User Cache</term>
                    <listitem>
                        Caches users and role-mappings to improve performance. Keycloak provides a basic in-memory
                        cache and a Infinispan cache.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>User Federation</term>
                    <listitem>
                        Support syncing users from an external source. Keycloak provides implementations for LDAP and
                        Active Directory.
                    </listitem>
                </varlistentry>
                <varlistentry>
                    <term>User Sessions</term>
                    <listitem>
                        Provides users session information. Keycloak provides implementations for basic in-memory,
                        Infinispan,
                        Relational Databases and MongoDB
                    </listitem>
                </varlistentry>
            </variablelist>
        </para>
    </section>
</chapter>
