Add Cache Filter for Parsed RequestPath

This exposes the management of the parsed and cached RequestPath.
It will be helpful in filter chains so the RequestPath is only parsed
once per dispatch.

Signed-off-by: Josh Cummings <[email protected]>

Author: jzheaux

spring-web/src/main/java/org/springframework/web/util/ServletRequestPathUtils.java

@@ -16,11 +16,16 @@
 
 package org.springframework.web.util;
 
+import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
 
+import jakarta.servlet.Filter;
+import jakarta.servlet.FilterChain;
 import jakarta.servlet.RequestDispatcher;
+import jakarta.servlet.ServletException;
 import jakarta.servlet.ServletRequest;
+import jakarta.servlet.ServletResponse;
 import jakarta.servlet.http.HttpServletMapping;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.MappingMatch;
@@ -110,6 +115,14 @@ public static void clearParsedRequestPath(ServletRequest request) {
 		request.removeAttribute(PATH_ATTRIBUTE);
 	}
 
+	/**
+	 * Provide a {@link Filter} that manages the parsing and caching of a {@link RequestPath}.
+	 * @return the described {@link Filter}
+	 * @since 6.2.3
+	 */
+	public static Filter getParsedRequestPathCacheFilter() {
+		return new RequestPathCacheFilter();
+	}
 
 	// Methods to select either parsed RequestPath or resolved String lookupPath
 
@@ -312,4 +325,20 @@ PathElements withContextPath(String contextPath) {
 		}
 	}
 
+	private static final class RequestPathCacheFilter implements Filter {
+		public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
+			if (!(req instanceof HttpServletRequest request)) {
+				chain.doFilter(req, res);
+				return;
+			}
+			RequestPath previousRequestPath = (RequestPath) request.getAttribute(PATH_ATTRIBUTE);
+			try {
+				parseAndCache(request);
+				chain.doFilter(req, res);
+			}
+			finally {
+				setParsedRequestPath(previousRequestPath, request);
+			}
+		}
+	}
 }

spring-web/src/test/java/org/springframework/web/util/ServletRequestPathUtilsTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2024 the original author or authors.
+ * Copyright 2002-2025 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.
@@ -16,6 +16,12 @@
 
 package org.springframework.web.util;
 
+import java.io.IOException;
+
+import jakarta.servlet.Filter;
+import jakarta.servlet.RequestDispatcher;
+import jakarta.servlet.ServletException;
+import jakarta.servlet.http.HttpServletMapping;
 import jakarta.servlet.http.MappingMatch;
 import org.junit.jupiter.api.Test;
 
@@ -88,6 +94,35 @@ void modifyPathContextWithContextPathEndingWithSlash() {
 				.withMessage("Invalid contextPath '/persons/': must start with '/' and not end with '/'");
 	}
 
+	@Test
+	void filterParsesAndCachesThenCleansUp() throws IOException, ServletException {
+		MockHttpServletRequest request = createRequest("/servlet/request", "", "/servlet", "/request");
+		Filter filter = ServletRequestPathUtils.getParsedRequestPathCacheFilter();
+		filter.doFilter(request, null, (req, res) -> {
+			RequestPath currentPath = ServletRequestPathUtils.getParsedRequestPath(request);
+			assertThat(currentPath.pathWithinApplication().value()).isEqualTo("/request");
+		});
+		assertThat(ServletRequestPathUtils.hasParsedRequestPath(request)).isFalse();
+	}
+
+	@Test
+	void filterParsesCachesAndThenRestores() throws IOException, ServletException {
+		MockHttpServletRequest request = createRequest("/servlet/request", "", "/servlet", "/request");
+		RequestPath requestPath = ServletRequestPathUtils.parseAndCache(request);
+
+		HttpServletMapping mapping = new MockHttpServletMapping("/include", "", "myServlet", MappingMatch.PATH);
+		request.setAttribute(RequestDispatcher.INCLUDE_MAPPING, mapping);
+		request.setAttribute(WebUtils.INCLUDE_SERVLET_PATH_ATTRIBUTE, "/servlet");
+		request.setAttribute(WebUtils.INCLUDE_REQUEST_URI_ATTRIBUTE, "/servlet/include");
+
+		Filter filter = ServletRequestPathUtils.getParsedRequestPathCacheFilter();
+		filter.doFilter(request, null, (req, res) -> {
+			RequestPath currentPath = ServletRequestPathUtils.getParsedRequestPath(request);
+			assertThat(currentPath.pathWithinApplication().value()).isEqualTo("/include");
+		});
+		assertThat(requestPath).isEqualTo(ServletRequestPathUtils.getParsedRequestPath(request));
+	}
+
 	private void testParseAndCache(
 			String requestUri, String contextPath, String servletPath, String pathWithinApplication) {
 
@@ -100,13 +135,19 @@ private void testParseAndCache(
 	private static RequestPath createRequestPath(
 			String requestUri, String contextPath, String servletPath, String pathWithinApplication) {
 
+		MockHttpServletRequest request = createRequest(requestUri, contextPath, servletPath, pathWithinApplication);
+		return ServletRequestPathUtils.parseAndCache(request);
+	}
+
+	private static MockHttpServletRequest createRequest(
+			String requestUri, String contextPath, String servletPath, String pathWithinApplication) {
+
 		MockHttpServletRequest request = new MockHttpServletRequest("GET", requestUri);
 		request.setContextPath(contextPath);
 		request.setServletPath(servletPath);
 		request.setHttpServletMapping(new MockHttpServletMapping(
 				pathWithinApplication, contextPath, "myServlet", MappingMatch.PATH));
-
-		return ServletRequestPathUtils.parseAndCache(request);
+		return request;
 	}
 
 }