Add How-to: Implement Multitenancy

Closes gh-663

docs/src/main/java/sample/multitenancy/OAuth2AuthorizationServiceConfig.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright 2020-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sample.multitenancy;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.sql.DataSource;
+
+import org.springframework.beans.factory.annotation.Qualifier;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.jdbc.core.JdbcTemplate;
+import org.springframework.security.oauth2.server.authorization.JdbcOAuth2AuthorizationService;
+import org.springframework.security.oauth2.server.authorization.OAuth2Authorization;
+import org.springframework.security.oauth2.server.authorization.OAuth2AuthorizationService;
+import org.springframework.security.oauth2.server.authorization.OAuth2TokenType;
+import org.springframework.security.oauth2.server.authorization.client.RegisteredClientRepository;
+import org.springframework.security.oauth2.server.authorization.context.AuthorizationServerContextHolder;
+
+@Configuration(proxyBeanMethods = false)
+public class OAuth2AuthorizationServiceConfig {
+
+	@Bean
+	public OAuth2AuthorizationService authorizationService(
+			@Qualifier("issuer1-data-source") DataSource issuer1DataSource,
+			@Qualifier("issuer2-data-source") DataSource issuer2DataSource,
+			RegisteredClientRepository registeredClientRepository) {
+
+		Map<String, OAuth2AuthorizationService> authorizationServiceMap = new HashMap<>();
+		authorizationServiceMap.put("issuer1", new JdbcOAuth2AuthorizationService(	// <1>
+				new JdbcTemplate(issuer1DataSource), registeredClientRepository));
+		authorizationServiceMap.put("issuer2", new JdbcOAuth2AuthorizationService(	// <2>
+				new JdbcTemplate(issuer2DataSource), registeredClientRepository));
+
+		return new DelegatingOAuth2AuthorizationService(authorizationServiceMap);
+	}
+
+	private static class DelegatingOAuth2AuthorizationService implements OAuth2AuthorizationService {	// <3>
+		private final Map<String, OAuth2AuthorizationService> authorizationServiceMap;
+
+		private DelegatingOAuth2AuthorizationService(Map<String, OAuth2AuthorizationService> authorizationServiceMap) {
+			this.authorizationServiceMap = authorizationServiceMap;
+		}
+
+		@Override
+		public void save(OAuth2Authorization authorization) {
+			OAuth2AuthorizationService authorizationService = getAuthorizationService();
+			if (authorizationService != null) {
+				authorizationService.save(authorization);
+			}
+		}
+
+		@Override
+		public void remove(OAuth2Authorization authorization) {
+			OAuth2AuthorizationService authorizationService = getAuthorizationService();
+			if (authorizationService != null) {
+				authorizationService.remove(authorization);
+			}
+		}
+
+		@Override
+		public OAuth2Authorization findById(String id) {
+			OAuth2AuthorizationService authorizationService = getAuthorizationService();
+			return (authorizationService != null) ?
+					authorizationService.findById(id) :
+					null;
+		}
+
+		@Override
+		public OAuth2Authorization findByToken(String token, OAuth2TokenType tokenType) {
+			OAuth2AuthorizationService authorizationService = getAuthorizationService();
+			return (authorizationService != null) ?
+					authorizationService.findByToken(token, tokenType) :
+					null;
+		}
+
+		private OAuth2AuthorizationService getAuthorizationService() {
+			if (AuthorizationServerContextHolder.getContext() == null ||
+					AuthorizationServerContextHolder.getContext().getIssuer() == null) {
+				return null;
+			}
+			String issuer = AuthorizationServerContextHolder.getContext().getIssuer();	// <4>
+			for (Map.Entry<String, OAuth2AuthorizationService> entry : this.authorizationServiceMap.entrySet()) {
+				if (issuer.endsWith(entry.getKey())) {
+					return entry.getValue();
+				}
+			}
+			return null;
+		}
+
+	}
+
+}