org.springframework.web.servlet.resource.ResourceUrlEncodingFilter Maven / Gradle / Ivy
/*
* Copyright 2002-2017 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
*
* http://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.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.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 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));
}
private static class ResourceUrlEncodingResponseWrapper extends HttpServletResponseWrapper {
private final HttpServletRequest request;
/* Cache the index and prefix of the path within the DispatcherServlet mapping */
@Nullable
private Integer indexLookupPath;
private String prefixLookupPath = "";
public ResourceUrlEncodingResponseWrapper(HttpServletRequest request, HttpServletResponse wrapped) {
super(wrapped);
this.request = request;
}
@Override
public String encodeURL(String url) {
ResourceUrlProvider resourceUrlProvider = getResourceUrlProvider();
if (resourceUrlProvider == null) {
logger.debug("Request attribute exposing ResourceUrlProvider not found");
return super.encodeURL(url);
}
int index = initLookupPath(resourceUrlProvider);
if (url.startsWith(this.prefixLookupPath)) {
int suffixIndex = getQueryParamsIndex(url);
String suffix = url.substring(suffixIndex);
String lookupPath = url.substring(index, suffixIndex);
lookupPath = resourceUrlProvider.getForLookupPath(lookupPath);
if (lookupPath != null) {
return super.encodeURL(this.prefixLookupPath + lookupPath + suffix);
}
}
return super.encodeURL(url);
}
@Nullable
private ResourceUrlProvider getResourceUrlProvider() {
return (ResourceUrlProvider) this.request.getAttribute(
ResourceUrlProviderExposingInterceptor.RESOURCE_URL_PROVIDER_ATTR);
}
private int initLookupPath(ResourceUrlProvider urlProvider) {
if (this.indexLookupPath == null) {
UrlPathHelper pathHelper = urlProvider.getUrlPathHelper();
String requestUri = pathHelper.getRequestUri(this.request);
String lookupPath = pathHelper.getLookupPathForRequest(this.request);
this.indexLookupPath = requestUri.lastIndexOf(lookupPath);
this.prefixLookupPath = requestUri.substring(0, this.indexLookupPath);
if ("/".equals(lookupPath) && !"/".equals(requestUri)) {
String contextPath = pathHelper.getContextPath(this.request);
if (requestUri.equals(contextPath)) {
this.indexLookupPath = requestUri.length();
this.prefixLookupPath = requestUri;
}
}
}
return this.indexLookupPath;
}
private int getQueryParamsIndex(String url) {
int index = url.indexOf('?');
return (index > 0 ? index : url.length());
}
}
}