Expose Principal in ServerRequest

This commit exposes the Principal in ServerRequest.

Issue: SPR-15552

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/DefaultServerRequest.java

@@ -19,6 +19,7 @@ package org.springframework.web.reactive.function.server;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.nio.charset.Charset;
+import java.security.Principal;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -157,6 +158,11 @@ class DefaultServerRequest implements ServerRequest {
 		return this.exchange.getSession();
 	}
 
+	@Override
+	public Mono<? extends Principal> principal() {
+		return this.exchange.getPrincipal();
+	}
+
 	private ServerHttpRequest request() {
 		return this.exchange.getRequest();
 	}

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/RequestPredicates.java

@@ -17,6 +17,7 @@
 package org.springframework.web.reactive.function.server;
 
 import java.net.URI;
+import java.security.Principal;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
@@ -543,6 +544,11 @@ public abstract class RequestPredicates {
 			return this.request.session();
 		}
 
+		@Override
+		public Mono<? extends Principal> principal() {
+			return this.request.principal();
+		}
+
 		@Override
 		public String toString() {
 			return method() + " " +  path();

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/ServerRequest.java

@@ -19,6 +19,7 @@ package org.springframework.web.reactive.function.server;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.nio.charset.Charset;
+import java.security.Principal;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -168,6 +169,11 @@ public interface ServerRequest {
 	 */
 	Mono<WebSession> session();
 
+	/**
+	 * Return the authenticated user for the request, if any.
+	 */
+	Mono<? extends Principal> principal();
+
 
 	/**
 	 * Represents the headers of the HTTP request.

spring-webflux/src/main/java/org/springframework/web/reactive/function/server/support/ServerRequestWrapper.java

@@ -19,6 +19,7 @@ package org.springframework.web.reactive.function.server.support;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.nio.charset.Charset;
+import java.security.Principal;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
@@ -144,6 +145,10 @@ public class ServerRequestWrapper implements ServerRequest {
 		return this.delegate.session();
 	}
 
+	@Override
+	public Mono<? extends Principal> principal() {
+		return this.delegate.principal();
+	}
 
 	/**
 	 * Implementation of the {@code Headers} interface that can be subclassed

spring-webflux/src/test/java/org/springframework/web/reactive/function/server/MockServerRequest.java

@@ -19,6 +19,7 @@ package org.springframework.web.reactive.function.server;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.nio.charset.Charset;
+import java.security.Principal;
 import java.time.Instant;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
@@ -66,11 +67,12 @@ public class MockServerRequest implements ServerRequest {
 
 	private final WebSession session;
 
+	private Principal principal;
 
 	private MockServerRequest(HttpMethod method, URI uri,
 			MockHeaders headers, Object body, Map<String, Object> attributes,
 			MultiValueMap<String, String> queryParams,
-			Map<String, String> pathVariables, WebSession session) {
+			Map<String, String> pathVariables, WebSession session, Principal principal) {
 
 		this.method = method;
 		this.uri = uri;
@@ -80,6 +82,7 @@ public class MockServerRequest implements ServerRequest {
 		this.queryParams = queryParams;
 		this.pathVariables = pathVariables;
 		this.session = session;
+		this.principal = principal;
 	}
 
 
@@ -148,6 +151,10 @@ public class MockServerRequest implements ServerRequest {
 		return Mono.justOrEmpty(this.session);
 	}
 
+	@Override
+	public Mono<? extends Principal> principal() {
+		return Mono.justOrEmpty(this.principal);
+	}
 
 	public static Builder builder() {
 		return new BuilderImpl();
@@ -178,6 +185,8 @@ public class MockServerRequest implements ServerRequest {
 
 		Builder session(WebSession session);
 
+		Builder session(Principal principal);
+
 		MockServerRequest body(Object body);
 
 		MockServerRequest build();
@@ -202,6 +211,8 @@ public class MockServerRequest implements ServerRequest {
 
 		private WebSession session;
 
+		private Principal principal;
+
 		@Override
 		public Builder method(HttpMethod method) {
 			Assert.notNull(method, "'method' must not be null");
@@ -283,17 +294,26 @@ public class MockServerRequest implements ServerRequest {
 			return this;
 		}
 
+		@Override
+		public Builder session(Principal principal) {
+			Assert.notNull(principal, "'principal' must not be null");
+			this.principal = principal;
+			return this;
+		}
+
 		@Override
 		public MockServerRequest body(Object body) {
 			this.body = body;
 			return new MockServerRequest(this.method, this.uri, this.headers, this.body,
-					this.attributes, this.queryParams, this.pathVariables, this.session);
+					this.attributes, this.queryParams, this.pathVariables, this.session,
+					this.principal);
 		}
 
 		@Override
 		public MockServerRequest build() {
 			return new MockServerRequest(this.method, this.uri, this.headers, null,
-					this.attributes, this.queryParams, this.pathVariables, this.session);
+					this.attributes, this.queryParams, this.pathVariables, this.session,
+					this.principal);
 		}
 	}