Automatically add CsrfServerLogoutHandler if csrf enabled

The configuration DSL should automatically add CsrfServerLogoutHandler if csrf is enabled

Fixes gh-5337

web/src/main/java/org/springframework/security/web/server/authentication/logout/DelegatingServerLogoutHandler.java

@@ -18,16 +18,17 @@ package org.springframework.security.web.server.authentication.logout;
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
+
+import reactor.core.publisher.Mono;
 
 import org.springframework.security.core.Authentication;
 import org.springframework.security.web.server.WebFilterExchange;
 import org.springframework.util.Assert;
 
-import reactor.core.publisher.Mono;
-
 /**
  * Delegates to a collection of {@link ServerLogoutHandler} implementations.
  *
@@ -35,21 +36,24 @@ import reactor.core.publisher.Mono;
  * @since 5.1
  */
 public class DelegatingServerLogoutHandler implements ServerLogoutHandler {
-	private final List<ServerLogoutHandler> delegates;
+	private final List<ServerLogoutHandler> delegates = new ArrayList<>();
 
 	public DelegatingServerLogoutHandler(ServerLogoutHandler... delegates) {
 		Assert.notEmpty(delegates, "delegates cannot be null or empty");
-		this.delegates = Arrays.asList(delegates);
+		this.delegates.addAll(Arrays.asList(delegates));
 	}
 
-	public DelegatingServerLogoutHandler(List<ServerLogoutHandler> delegates) {
+	public DelegatingServerLogoutHandler(Collection<ServerLogoutHandler> delegates) {
 		Assert.notEmpty(delegates, "delegates cannot be null or empty");
-		this.delegates = new ArrayList<>(delegates);
+		this.delegates.addAll(delegates);
 	}
 
 	@Override
 	public Mono<Void> logout(WebFilterExchange exchange, Authentication authentication) {
-		Stream<Mono<Void>> results = this.delegates.stream().map(delegate -> delegate.logout(exchange, authentication));
-		return Mono.when(results.collect(Collectors.toList()));
+		return Mono.when(this.delegates.stream()
+				.filter(Objects::nonNull)
+				.map(delegate -> delegate.logout(exchange, authentication))
+				.collect(Collectors.toList())
+		);
 	}
 }

web/src/main/java/org/springframework/security/web/server/authentication/logout/LogoutWebFilter.java

@@ -16,17 +16,17 @@
 
 package org.springframework.security.web.server.authentication.logout;
 
-import org.springframework.http.HttpMethod;
-import org.springframework.security.core.context.ReactiveSecurityContextHolder;
-import org.springframework.util.Assert;
 import reactor.core.publisher.Mono;
 
+import org.springframework.http.HttpMethod;
 import org.springframework.security.authentication.AnonymousAuthenticationToken;
 import org.springframework.security.core.Authentication;
 import org.springframework.security.core.authority.AuthorityUtils;
+import org.springframework.security.core.context.ReactiveSecurityContextHolder;
 import org.springframework.security.web.server.WebFilterExchange;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatcher;
 import org.springframework.security.web.server.util.matcher.ServerWebExchangeMatchers;
+import org.springframework.util.Assert;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.WebFilter;
 import org.springframework.web.server.WebFilterChain;
@@ -85,6 +85,10 @@ public class LogoutWebFilter implements WebFilter {
 		this.logoutSuccessHandler = logoutSuccessHandler;
 	}
 
+	/**
+	 * Sets the {@link ServerLogoutHandler}. The default is {@link SecurityContextServerLogoutHandler}.
+	 * @param logoutHandler The handler to use
+	 */
 	public void setLogoutHandler(ServerLogoutHandler logoutHandler) {
 		Assert.notNull(logoutHandler, "logoutHandler must not be null");
 		this.logoutHandler = logoutHandler;

web/src/test/java/org/springframework/security/web/server/authentication/logout/LogoutWebFilterTests.java

@@ -0,0 +1,86 @@
+/*
+ * Copyright 2002-2018 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
+ *
+ *      http://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.security.web.server.authentication.logout;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.stream.Collectors;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import org.springframework.test.util.ReflectionTestUtils;
+
+/**
+ * @author Eric Deandrea
+ * @since  5.1
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class LogoutWebFilterTests {
+	@Mock
+	private ServerLogoutHandler handler1;
+
+	@Mock
+	private ServerLogoutHandler handler2;
+
+	@Mock
+	private ServerLogoutHandler handler3;
+
+	private LogoutWebFilter logoutWebFilter = new LogoutWebFilter();
+
+	@Test
+	public void defaultLogoutHandler() {
+		assertThat(getLogoutHandler())
+				.isNotNull()
+				.isExactlyInstanceOf(SecurityContextServerLogoutHandler.class);
+	}
+
+	@Test
+	public void singleLogoutHandler() {
+		this.logoutWebFilter.setLogoutHandler(this.handler1);
+		this.logoutWebFilter.setLogoutHandler(this.handler2);
+
+		assertThat(getLogoutHandler())
+				.isNotNull()
+				.isInstanceOf(ServerLogoutHandler.class)
+				.isNotInstanceOf(SecurityContextServerLogoutHandler.class)
+				.extracting(ServerLogoutHandler::getClass)
+				.isEqualTo(this.handler2.getClass());
+	}
+
+	@Test
+	public void multipleLogoutHandlers() {
+		this.logoutWebFilter.setLogoutHandler(new DelegatingServerLogoutHandler(this.handler1, this.handler2, this.handler3));
+
+		assertThat(getLogoutHandler())
+				.isNotNull()
+				.isExactlyInstanceOf(DelegatingServerLogoutHandler.class)
+				.extracting(delegatingLogoutHandler -> ((Collection<ServerLogoutHandler>) ReflectionTestUtils.getField(delegatingLogoutHandler, DelegatingServerLogoutHandler.class, "delegates"))
+						.stream()
+						.map(ServerLogoutHandler::getClass)
+						.collect(Collectors.toList()))
+				.isEqualTo(Arrays.asList(this.handler1.getClass(), this.handler2.getClass(), this.handler3.getClass()));
+	}
+
+	private ServerLogoutHandler getLogoutHandler() {
+		return (ServerLogoutHandler) ReflectionTestUtils.getField(this.logoutWebFilter, LogoutWebFilter.class, "logoutHandler");
+	}
+}