Add ReactiveRedisIndexedSessionRepository

Closes gh-2700

spring-session-core/src/main/java/org/springframework/session/PrincipalNameIndexResolver.java

@@ -38,6 +38,15 @@ public class PrincipalNameIndexResolver<S extends Session> extends SingleIndexRe
 		super(FindByIndexNameSessionRepository.PRINCIPAL_NAME_INDEX_NAME);
 	}
 
+	/**
+	 * Create a new instance specifying the name of the index to be resolved.
+	 * @param indexName the name of the index to be resolved
+	 * @since 3.3
+	 */
+	public PrincipalNameIndexResolver(String indexName) {
+		super(indexName);
+	}
+
 	public String resolveIndexValueFor(S session) {
 		String principalName = session.getAttribute(getIndexName());
 		if (principalName != null) {

spring-session-core/src/main/java/org/springframework/session/ReactiveFindByIndexNameSessionRepository.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2014-2023 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 org.springframework.session;
+
+import java.util.Map;
+
+import reactor.core.publisher.Mono;
+
+/**
+ * Allow finding sessions by the specified index name and index value.
+ *
+ * @param <S> the type of Session being managed by this
+ * {@link ReactiveFindByIndexNameSessionRepository}
+ * @author Marcus da Coregio
+ * @since 3.3
+ */
+public interface ReactiveFindByIndexNameSessionRepository<S extends Session> {
+
+	/**
+	 * A session index that contains the current principal name (i.e. username).
+	 * <p>
+	 * It is the responsibility of the developer to ensure the index is populated since
+	 * Spring Session is not aware of the authentication mechanism being used.
+	 */
+	String PRINCIPAL_NAME_INDEX_NAME = "PRINCIPAL_NAME_INDEX_NAME";
+
+	/**
+	 * Find a {@link Map} of the session id to the {@link Session} of all sessions that
+	 * contain the specified index name index value.
+	 * @param indexName the name of the index (i.e. {@link #PRINCIPAL_NAME_INDEX_NAME})
+	 * @param indexValue the value of the index to search for.
+	 * @return a {@code Map} (never {@code null}) of the session id to the {@code Session}
+	 */
+	Mono<Map<String, S>> findByIndexNameAndIndexValue(String indexName, String indexValue);
+
+	/**
+	 * A shortcut for {@link #findByIndexNameAndIndexValue(String, String)} that uses
+	 * {@link #PRINCIPAL_NAME_INDEX_NAME} for the index name.
+	 * @param principalName the principal name
+	 * @return a {@code Map} (never {@code null}) of the session id to the {@code Session}
+	 */
+	default Mono<Map<String, S>> findByPrincipalName(String principalName) {
+		return findByIndexNameAndIndexValue(PRINCIPAL_NAME_INDEX_NAME, principalName);
+	}
+
+}