Add ServerAuthenticationConverter interface

- Adding an ServerAuthenticationConverter interface
- Retro-fitting ServerOAuth2LoginAuthenticationTokenConverter,
 ServerBearerTokenAuthentivationConverter, ServerFormLoginAuthenticationConverter,
 and ServerHttpBasicAuthenticationConverter to implement ServerAuthenticationConverter
- Deprecate existing AuthenticationWebFilter.setAuthenticationConverter
and add overloaded one which takes ServerAuthenticationConverter

Fixes gh-5338

web/src/main/java/org/springframework/security/web/server/ServerFormLoginAuthenticationConverter.java

@@ -15,8 +15,7 @@
  */
 package org.springframework.security.web.server;
 
-import java.util.function.Function;
-
+import org.springframework.security.web.server.authentication.ServerAuthenticationConverter;
 import org.springframework.util.Assert;
 import reactor.core.publisher.Mono;
 
@@ -32,14 +31,14 @@ import org.springframework.web.server.ServerWebExchange;
  * @author Rob Winch
  * @since 5.0
  */
-public class ServerFormLoginAuthenticationConverter implements Function<ServerWebExchange, Mono<Authentication>> {
+public class ServerFormLoginAuthenticationConverter implements ServerAuthenticationConverter {
 
 	private String usernameParameter = "username";
 
 	private String passwordParameter = "password";
 
 	@Override
-	public Mono<Authentication> apply(ServerWebExchange exchange) {
+	public Mono<Authentication> convert(ServerWebExchange exchange) {
 		return exchange.getFormData()
 			.map( data -> createAuthentication(data));
 	}

web/src/main/java/org/springframework/security/web/server/ServerHttpBasicAuthenticationConverter.java

@@ -16,12 +16,12 @@
 package org.springframework.security.web.server;
 
 import java.util.Base64;
-import java.util.function.Function;
 
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.server.reactive.ServerHttpRequest;
 import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
 import org.springframework.security.core.Authentication;
+import org.springframework.security.web.server.authentication.ServerAuthenticationConverter;
 import org.springframework.web.server.ServerWebExchange;
 
 import reactor.core.publisher.Mono;
@@ -32,12 +32,12 @@ import reactor.core.publisher.Mono;
  * @author Rob Winch
  * @since 5.0
  */
-public class ServerHttpBasicAuthenticationConverter implements Function<ServerWebExchange, Mono<Authentication>> {
+public class ServerHttpBasicAuthenticationConverter implements ServerAuthenticationConverter {
 
 	public static final String BASIC = "Basic ";
 
 	@Override
-	public Mono<Authentication> apply(ServerWebExchange exchange) {
+	public Mono<Authentication> convert(ServerWebExchange exchange) {
 		ServerHttpRequest request = exchange.getRequest();
 
 		String authorization = request.getHeaders().getFirst(HttpHeaders.AUTHORIZATION);

web/src/main/java/org/springframework/security/web/server/authentication/AuthenticationWebFilter.java

@@ -67,7 +67,7 @@ public class AuthenticationWebFilter implements WebFilter {
 
 	private ServerAuthenticationSuccessHandler authenticationSuccessHandler = new WebFilterChainServerAuthenticationSuccessHandler();
 
-	private Function<ServerWebExchange, Mono<Authentication>> authenticationConverter = new ServerHttpBasicAuthenticationConverter();
+	private ServerAuthenticationConverter authenticationConverter = new ServerHttpBasicAuthenticationConverter();
 
 	private ServerAuthenticationFailureHandler authenticationFailureHandler = new ServerAuthenticationEntryPointFailureHandler(new HttpBasicServerAuthenticationEntryPoint());
 
@@ -88,7 +88,7 @@ public class AuthenticationWebFilter implements WebFilter {
 	public Mono<Void> filter(ServerWebExchange exchange, WebFilterChain chain) {
 		return this.requiresAuthenticationMatcher.matches(exchange)
 			.filter( matchResult -> matchResult.isMatch())
-			.flatMap( matchResult -> this.authenticationConverter.apply(exchange))
+			.flatMap( matchResult -> this.authenticationConverter.convert(exchange))
 			.switchIfEmpty(chain.filter(exchange).then(Mono.empty()))
 			.flatMap( token -> authenticate(exchange, chain, token));
 	}
@@ -138,8 +138,24 @@ public class AuthenticationWebFilter implements WebFilter {
 	 * that no authentication attempt should be made. The default converter is
 	 * {@link ServerHttpBasicAuthenticationConverter}
 	 * @param authenticationConverter the converter to use
+	 * @deprecated As of 5.1 in favor of {@link #setAuthenticationConverter(ServerAuthenticationConverter)}
+	 * @see #setAuthenticationConverter(ServerAuthenticationConverter)
 	 */
+	@Deprecated
 	public void setAuthenticationConverter(Function<ServerWebExchange, Mono<Authentication>> authenticationConverter) {
+		Assert.notNull(authenticationConverter, "authenticationConverter cannot be null");
+		setAuthenticationConverter((ServerAuthenticationConverter) authenticationConverter);
+	}
+
+	/**
+	 * Sets the strategy used for converting from a {@link ServerWebExchange} to an {@link Authentication} used for
+	 * authenticating with the provided {@link ReactiveAuthenticationManager}. If the result is empty, then it signals
+	 * that no authentication attempt should be made. The default converter is
+	 * {@link ServerHttpBasicAuthenticationConverter}
+	 * @param authenticationConverter the converter to use
+	 * @since 5.1
+	 */
+	public void setAuthenticationConverter(ServerAuthenticationConverter authenticationConverter) {
 		Assert.notNull(authenticationConverter, "authenticationConverter cannot be null");
 		this.authenticationConverter = authenticationConverter;
 	}
@@ -156,7 +172,7 @@ public class AuthenticationWebFilter implements WebFilter {
 
 	/**
 	 * Sets the matcher used to determine when creating an {@link Authentication} from
-	 * {@link #setAuthenticationConverter(Function)} to be authentication. If the converter returns an empty
+	 * {@link #setAuthenticationConverter(ServerAuthenticationConverter)} to be authentication. If the converter returns an empty
 	 * result, then no authentication is attempted. The default is any request
 	 * @param requiresAuthenticationMatcher the matcher to use. Cannot be null.
 	 */

web/src/main/java/org/springframework/security/web/server/authentication/ServerAuthenticationConverter.java

@@ -0,0 +1,40 @@
+/*
+ * 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;
+
+import org.springframework.security.core.Authentication;
+import org.springframework.web.server.ServerWebExchange;
+
+import reactor.core.publisher.Mono;
+
+/**
+ * A strategy used for converting from a {@link ServerWebExchange} to an {@link Authentication} used for
+ * authenticating with a provided {@link org.springframework.security.authentication.ReactiveAuthenticationManager}.
+ * If the result is {@link Mono#empty()}, then it signals that no authentication attempt should be made.
+ *
+ * @author Eric Deandrea
+ * @since 5.1
+ */
+@FunctionalInterface
+public interface ServerAuthenticationConverter {
+	/**
+	 * Converts a {@link ServerWebExchange} to an {@link Authentication}
+	 * @param exchange The {@link ServerWebExchange}
+	 * @return A {@link Mono} representing an {@link Authentication}
+	 */
+	Mono<Authentication> convert(ServerWebExchange exchange);
+}