Path RequestPredicate should honor servlet path

Closes gh-23841

Author: poutsma

spring-webmvc/src/main/java/org/springframework/web/servlet/function/DefaultServerRequest.java

@@ -54,8 +54,10 @@
 import org.springframework.util.MultiValueMap;
 import org.springframework.util.ObjectUtils;
 import org.springframework.web.HttpMediaTypeNotSupportedException;
+import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
 import org.springframework.web.util.UriBuilder;
+import org.springframework.web.util.UrlPathHelper;
 
 /**
  * {@code ServerRequest} implementation based on a {@link HttpServletRequest}.
@@ -111,6 +113,16 @@ public UriBuilder uriBuilder() {
 		return ServletUriComponentsBuilder.fromRequest(servletRequest());
 	}
 
+	@Override
+	public String path() {
+		String path = (String) servletRequest().getAttribute(HandlerMapping.LOOKUP_PATH);
+		if (path == null) {
+			UrlPathHelper helper = new UrlPathHelper();
+			path = helper.getLookupPathForRequest(servletRequest());
+		}
+		return path;
+	}
+
 	@Override
 	public Headers headers() {
 		return this.headers;

spring-webmvc/src/main/java/org/springframework/web/servlet/function/support/RouterFunctionMapping.java

@@ -168,6 +168,8 @@ private void initMessageConverters() {
 	@Nullable
 	@Override
 	protected Object getHandlerInternal(@NotNull HttpServletRequest servletRequest) throws Exception {
+		String lookupPath = getUrlPathHelper().getLookupPathForRequest(servletRequest);
+		servletRequest.setAttribute(LOOKUP_PATH, lookupPath);
 		if (this.routerFunction != null) {
 			ServerRequest request = ServerRequest.create(servletRequest, this.messageConverters);
 			servletRequest.setAttribute(RouterFunctions.REQUEST_ATTRIBUTE, request);

spring-webmvc/src/test/java/org/springframework/web/servlet/function/RequestPredicatesTests.java

@@ -116,6 +116,19 @@ public void path() {
 		assertThat(predicate.test(request)).isFalse();
 	}
 
+	@Test
+	public void servletPath() {
+		MockHttpServletRequest servletRequest = new MockHttpServletRequest("GET", "/foo/bar");
+		servletRequest.setServletPath("/foo");
+		ServerRequest request = new DefaultServerRequest(servletRequest, emptyList());
+		RequestPredicate predicate = RequestPredicates.path("/bar");
+		assertThat(predicate.test(request)).isTrue();
+
+		servletRequest = new MockHttpServletRequest("GET", "/foo");
+		request = new DefaultServerRequest(servletRequest, emptyList());
+		assertThat(predicate.test(request)).isFalse();
+	}
+
 	@Test
 	public void pathNoLeadingSlash() {
 		MockHttpServletRequest servletRequest = new MockHttpServletRequest("GET", "/path");