Do not execute ResourceUrlEncodingFilter only once per request

In case the filter is also registered to the ERROR dispatcher, the
following happens:
* the filter is executed once for the regular execution
* the filter should be executed a second time when dispatched to error

Since the filter is a `OncePerRequestFilter`, the filter is only
executed once and won't be executed when handling the error.

This can lead to situations like spring-projects/spring-boot#7348

This commit makes this filter a simple `GenericFilterBean`.

Issue: SPR-14891

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

@@ -19,6 +19,8 @@ package org.springframework.web.servlet.resource;
 import java.io.IOException;
 import javax.servlet.FilterChain;
 import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import javax.servlet.http.HttpServletResponseWrapper;
@@ -26,7 +28,7 @@ import javax.servlet.http.HttpServletResponseWrapper;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.web.filter.OncePerRequestFilter;
+import org.springframework.web.filter.GenericFilterBean;
 import org.springframework.web.util.UrlPathHelper;
 
 /**
@@ -41,16 +43,20 @@ import org.springframework.web.util.UrlPathHelper;
  * @author Brian Clozel
  * @since 4.1
  */
-public class ResourceUrlEncodingFilter extends OncePerRequestFilter {
+public class ResourceUrlEncodingFilter extends GenericFilterBean {
 
 	private static final Log logger = LogFactory.getLog(ResourceUrlEncodingFilter.class);
 
 
 	@Override
-	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
-			throws ServletException, IOException {
-
-		filterChain.doFilter(request, new ResourceUrlEncodingResponseWrapper(request, response));
+	public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
+			throws IOException, ServletException {
+		if (!(request instanceof HttpServletRequest) || !(response instanceof HttpServletResponse)) {
+			throw new ServletException("ResourceUrlEncodingFilter just supports HTTP requests");
+		}
+		HttpServletRequest httpRequest = (HttpServletRequest) request;
+		HttpServletResponse httpResponse = (HttpServletResponse) response;
+		filterChain.doFilter(httpRequest, new ResourceUrlEncodingResponseWrapper(httpRequest, httpResponse));
 	}
 
 

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

@@ -15,15 +15,9 @@
  */
 package org.springframework.web.servlet.resource;
 
-import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
-
-import javax.servlet.FilterChain;
-import javax.servlet.ServletException;
-import javax.servlet.ServletRequest;
-import javax.servlet.ServletResponse;
 import javax.servlet.http.HttpServletResponse;
 
 import org.junit.Before;
@@ -33,7 +27,7 @@ import org.springframework.core.io.ClassPathResource;
 import org.springframework.mock.web.test.MockHttpServletRequest;
 import org.springframework.mock.web.test.MockHttpServletResponse;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
 
 /**
  * Unit tests for {@code ResourceUrlEncodingFilter}.
@@ -64,12 +58,9 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
-				String result = ((HttpServletResponse)response).encodeURL("/resources/bar.css");
-				assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
-			}
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("/resources/bar.css");
+			assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
 		});
 	}
 
@@ -80,12 +71,9 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
-				String result = ((HttpServletResponse)response).encodeURL("/context/resources/bar.css");
-				assertEquals("/context/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
-			}
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("/context/resources/bar.css");
+			assertEquals("/context/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
 		});
 	}
 
@@ -97,8 +85,8 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, (request1, response1) -> {
-			String result = ((HttpServletResponse) response1).encodeURL("/context/resources/bar.css");
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("/context/resources/bar.css");
 			assertEquals("/context/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
 		});
 	}
@@ -110,8 +98,8 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, (request1, response1) -> {
-			String result = ((HttpServletResponse) response1).encodeURL("/context/resources/bar.css");
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("/context/resources/bar.css");
 			assertEquals("/context/resources/bar-11e16cf79faee7ac698c805cf28248d2.css", result);
 		});
 	}
@@ -124,12 +112,9 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
-				String result = ((HttpServletResponse)response).encodeURL("?foo=1");
-				assertEquals("?foo=1", result);
-			}
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("?foo=1");
+			assertEquals("?foo=1", result);
 		});
 	}
 
@@ -141,12 +126,9 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
-				String result = ((HttpServletResponse)response).encodeURL("/resources/bar.css?foo=bar&url=http://example.org");
-				assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css?foo=bar&url=http://example.org", result);
-			}
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("/resources/bar.css?foo=bar&url=http://example.org");
+			assertEquals("/resources/bar-11e16cf79faee7ac698c805cf28248d2.css?foo=bar&url=http://example.org", result);
 		});
 	}
 
@@ -159,12 +141,9 @@ public class ResourceUrlEncodingFilterTests {
 		request.setAttribute(ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR, this.resourceUrlProvider);
 		MockHttpServletResponse response = new MockHttpServletResponse();
 
-		this.filter.doFilterInternal(request, response, new FilterChain() {
-			@Override
-			public void doFilter(ServletRequest request, ServletResponse response) throws IOException, ServletException {
-				String result = ((HttpServletResponse)response).encodeURL("index?key=value");
-				assertEquals("index?key=value", result);
-			}
+		this.filter.doFilter(request, response, (req, res) -> {
+			String result = ((HttpServletResponse) res).encodeURL("index?key=value");
+			assertEquals("index?key=value", result);
 		});
 	}