Add authcodegrant-webflux sample

Issue: gh-5620

samples/boot/authcodegrant-webflux/src/main/java/sample/config/SecurityConfig.java

@@ -0,0 +1,62 @@
+/*
+ * 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 sample.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
+import org.springframework.security.config.web.server.ServerHttpSecurity;
+import org.springframework.security.core.userdetails.MapReactiveUserDetailsService;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.core.userdetails.UserDetails;
+import org.springframework.security.oauth2.client.ReactiveOAuth2AuthorizedClientService;
+import org.springframework.security.oauth2.client.web.server.AuthenticatedPrincipalServerOAuth2AuthorizedClientRepository;
+import org.springframework.security.oauth2.client.web.server.ServerOAuth2AuthorizedClientRepository;
+import org.springframework.security.web.server.SecurityWebFilterChain;
+
+/**
+ * @author Rob Winch
+ */
+@EnableWebFluxSecurity
+public class SecurityConfig {
+
+	@Bean
+	SecurityWebFilterChain configure(ServerHttpSecurity http) throws Exception {
+		http
+			.authorizeExchange()
+				.anyExchange().authenticated()
+				.and()
+			.formLogin()
+				.and()
+			.oauth2()
+				.client();
+		return http.build();
+	}
+
+	@Bean
+	ServerOAuth2AuthorizedClientRepository authorizedClientRepository(ReactiveOAuth2AuthorizedClientService authorizedClientService) {
+		return new AuthenticatedPrincipalServerOAuth2AuthorizedClientRepository(authorizedClientService);
+	}
+
+	@Bean
+	MapReactiveUserDetailsService userDetailsService() {
+		UserDetails userDetails = User.withDefaultPasswordEncoder()
+			.username("user")
+			.password("password")
+			.roles("USER")
+			.build();
+		return new MapReactiveUserDetailsService(userDetails);
+	}
+}