/* * Copyright 2002-2019 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. * You may obtain a copy of the License at * * https://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ 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.HttpServletRequestWrapper; import javax.servlet.http.HttpServletResponse; import javax.servlet.http.HttpServletResponseWrapper; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.lang.Nullable; import org.springframework.util.Assert; import org.springframework.web.filter.GenericFilterBean; import org.springframework.web.util.UrlPathHelper; /** * A filter that wraps the {@link HttpServletResponse} and overrides its * {@link HttpServletResponse#encodeURL(String) encodeURL} method in order to * translate internal resource request URLs into public URL paths for external use. * * @author Jeremy Grelle * @author Rossen Stoyanchev * @author Sam Brannen * @author Brian Clozel * @since 4.1 */ public class ResourceUrlEncodingFilter extends GenericFilterBean { private static final Log logger = LogFactory.getLog(ResourceUrlEncodingFilter.class); @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws ServletException, IOException { if (!(request instanceof HttpServletRequest) || !(response instanceof HttpServletResponse)) { throw new ServletException("ResourceUrlEncodingFilter only supports HTTP requests"); } ResourceUrlEncodingRequestWrapper wrappedRequest = new ResourceUrlEncodingRequestWrapper((HttpServletRequest) request); ResourceUrlEncodingResponseWrapper wrappedResponse = new ResourceUrlEncodingResponseWrapper(wrappedRequest, (HttpServletResponse) response); filterChain.doFilter(wrappedRequest, wrappedResponse); } private static class ResourceUrlEncodingRequestWrapper extends HttpServletRequestWrapper { @Nullable private ResourceUrlProvider resourceUrlProvider; @Nullable private Integer indexLookupPath; private String prefixLookupPath = ""; ResourceUrlEncodingRequestWrapper(HttpServletRequest request) { super(request); } @Override public void setAttribute(String name, Object value) { super.setAttribute(name, value); if (ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR.equals(name)) { if (value instanceof ResourceUrlProvider) { initLookupPath((ResourceUrlProvider) value); } } } private void initLookupPath(ResourceUrlProvider urlProvider) { this.resourceUrlProvider = urlProvider; if (this.indexLookupPath == null) { UrlPathHelper pathHelper = this.resourceUrlProvider.getUrlPathHelper(); String requestUri = pathHelper.getRequestUri(this); String lookupPath = pathHelper.getLookupPathForRequest(this); this.indexLookupPath = requestUri.lastIndexOf(lookupPath); Assert.isTrue(this.indexLookupPath != -1, () -> "Failed to find lookupPath '" + lookupPath + "' within requestUri '" + requestUri + ". " + "Does the path have invalid encoded characters " + "for characterEncoding=" + getRequest().getCharacterEncoding() + "?"); this.prefixLookupPath = requestUri.substring(0, this.indexLookupPath); if ("/".equals(lookupPath) && !"/".equals(requestUri)) { String contextPath = pathHelper.getContextPath(this); if (requestUri.equals(contextPath)) { this.indexLookupPath = requestUri.length(); this.prefixLookupPath = requestUri; } } } } @Nullable public String resolveUrlPath(String url) { if (this.resourceUrlProvider == null) { logger.trace("ResourceUrlProvider not available via request attribute " + "ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR"); return null; } if (this.indexLookupPath != null && url.startsWith(this.prefixLookupPath)) { int suffixIndex = getEndPathIndex(url); String suffix = url.substring(suffixIndex); String lookupPath = url.substring(this.indexLookupPath, suffixIndex); lookupPath = this.resourceUrlProvider.getForLookupPath(lookupPath); if (lookupPath != null) { return this.prefixLookupPath + lookupPath + suffix; } } return null; } private int getEndPathIndex(String path) { int end = path.indexOf('?'); int fragmentIndex = path.indexOf('#'); if (fragmentIndex != -1 && (end == -1 || fragmentIndex < end)) { end = fragmentIndex; } if (end == -1) { end = path.length(); } return end; } } private static class ResourceUrlEncodingResponseWrapper extends HttpServletResponseWrapper { private final ResourceUrlEncodingRequestWrapper request; ResourceUrlEncodingResponseWrapper(ResourceUrlEncodingRequestWrapper request, HttpServletResponse wrapped) { super(wrapped); this.request = request; } @Override public String encodeURL(String url) { String urlPath = this.request.resolveUrlPath(url); if (urlPath != null) { return super.encodeURL(urlPath); } return super.encodeURL(url); } } }