Prepend leading slash in ResourceUrlProvider

The getForRequestUrl method of ResourceUrlProvider uses the
HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE attribute to
determine the relevant portion of the resource URL path.

However there are cases when that attribute may not have a leading
(e.g. when the current URL was matched to a prefix-based pattern
and hence extracted via PathMatcher#extractPathWithinPattern), which
interferes with the matching of resource URL paths to patterns.

This change ensures a leading slash is present

Issue: SPR-12281

spring-webmvc/src/main/java/org/springframework/web/servlet/resource/ResourceUrlProvider.java

@@ -179,6 +179,9 @@ public class ResourceUrlProvider implements ApplicationListener<ContextRefreshed
 			pathWithinMapping = getPathHelper().getLookupPathForRequest(request);
 		}
 
+		// When extracted with PathMatcher, pathWithinMapping won't have leading slash
+		pathWithinMapping = (pathWithinMapping.charAt(0) == '/' ? pathWithinMapping : "/" + pathWithinMapping);
+
 		int index = getPathHelper().getRequestUri(request).indexOf(pathWithinMapping);
 		Assert.state(index != -1, "Failed to determine lookup path: " + requestUrl);
 

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/ResourceHttpRequestHandlerTests.java

@@ -69,7 +69,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void getResource() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
 		this.handler.handleRequest(this.request, this.response);
 
 		assertEquals("text/css", this.response.getContentType());
@@ -83,7 +83,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void getResourceWithHtmlMediaType() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.html");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.html");
 		this.handler.handleRequest(this.request, this.response);
 
 		assertEquals("text/html", this.response.getContentType());
@@ -95,7 +95,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void getResourceFromAlternatePath() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/baz.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "baz.css");
 		this.handler.handleRequest(this.request, this.response);
 
 		assertEquals("text/css", this.response.getContentType());
@@ -109,7 +109,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void getResourceFromSubDirectory() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/js/foo.js");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/foo.js");
 		this.handler.handleRequest(this.request, this.response);
 
 		assertEquals("text/javascript", this.response.getContentType());
@@ -118,7 +118,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void getResourceFromSubDirectoryOfAlternatePath() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/js/baz.js");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/baz.js");
 		this.handler.handleRequest(this.request, this.response);
 
 		assertEquals("text/javascript", this.response.getContentType());
@@ -147,7 +147,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void notModified() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
 		this.request.addHeader("If-Modified-Since", resourceLastModified("test/foo.css"));
 		this.handler.handleRequest(this.request, this.response);
 		assertEquals(HttpServletResponse.SC_NOT_MODIFIED, this.response.getStatus());
@@ -155,7 +155,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void modified() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
 		this.request.addHeader("If-Modified-Since", resourceLastModified("test/foo.css") / 1000 * 1000 - 1);
 		this.handler.handleRequest(this.request, this.response);
 		assertEquals(HttpServletResponse.SC_OK, this.response.getStatus());
@@ -164,7 +164,7 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test
 	public void directory() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/js/");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "js/");
 		this.handler.handleRequest(this.request, this.response);
 		assertEquals(404, this.response.getStatus());
 	}
@@ -183,14 +183,14 @@ public class ResourceHttpRequestHandlerTests {
 
 	@Test(expected=HttpRequestMethodNotSupportedException.class)
 	public void unsupportedHttpMethod() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/foo.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "foo.css");
 		this.request.setMethod("POST");
 		this.handler.handleRequest(this.request, this.response);
 	}
 
 	@Test
 	public void resourceNotFound() throws Exception {
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/not-there.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "not-there.css");
 		this.handler.handleRequest(this.request, this.response);
 		assertEquals(404, this.response.getStatus());
 	}

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/ResourceTransformerSupportTests.java

@@ -72,7 +72,7 @@ public class ResourceTransformerSupportTests {
 	@Test
 	public void resolveUrlPath() throws Exception {
 		this.request.setRequestURI("/context/servlet/resources/main.css");
-		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "/resources/main.css");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "resources/main.css");
 
 		String resourcePath = "/context/servlet/resources/bar.css";
 		Resource css = new ClassPathResource("test/main.css", getClass());

spring-webmvc/src/test/java/org/springframework/web/servlet/resource/ResourceUrlProviderJavaConfigTests.java

@@ -28,6 +28,7 @@ import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
 import org.springframework.mock.web.test.MockServletContext;
 import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
+import org.springframework.web.servlet.HandlerMapping;
 import org.springframework.web.servlet.config.annotation.*;
 
 import static org.junit.Assert.*;
@@ -68,7 +69,6 @@ public class ResourceUrlProviderJavaConfigTests {
 		this.request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, urlProvider);
 	}
 
-
 	@Test
 	public void resolvePathWithRootServletMapping() throws Exception {
 		this.request.setRequestURI("/myapp/index");
@@ -99,6 +99,19 @@ public class ResourceUrlProviderJavaConfigTests {
 				resolvePublicResourceUrlPath("/myapp/resources/foo.css"));
 	}
 
+	// SPR-12281
+
+	@Test
+	public void resolvePathWithHandlerMappingAttribute() throws Exception {
+		this.request.setRequestURI("/myapp/index");
+		this.request.setServletPath("/index");
+		this.request.setAttribute(HandlerMapping.PATH_WITHIN_HANDLER_MAPPING_ATTRIBUTE, "index");
+		this.filterChain.doFilter(this.request, this.response);
+
+		assertEquals("/myapp/resources/foo-e36d2e05253c6c7085a91522ce43a0b4.css",
+				resolvePublicResourceUrlPath("/myapp/resources/foo.css"));
+	}
+
 	private String resolvePublicResourceUrlPath(String path) {
 		return this.servlet.wrappedResponse.encodeURL(path);
 	}