/*
* 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.filter;
import java.io.IOException;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import org.springframework.http.HttpRequest;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.util.CollectionUtils;
import org.springframework.util.LinkedCaseInsensitiveMap;
import org.springframework.util.StringUtils;
import org.springframework.web.util.UriComponents;
import org.springframework.web.util.UriComponentsBuilder;
import org.springframework.web.util.UrlPathHelper;
/**
* Filter that wraps the request and response in order to override its
* {@link HttpServletRequest#getServerName() getServerName()},
* {@link HttpServletRequest#getServerPort() getServerPort()},
* {@link HttpServletRequest#getScheme() getScheme()},
* {@link HttpServletRequest#isSecure() isSecure()},
* {@link HttpServletResponse#sendRedirect(String) sendRedirect(String)},
* methods with values derived from "Forwarded" or "X-Forwarded-*"
* headers. In effect the wrapped request and response reflects the
* client-originated protocol and address.
*
* @author Rossen Stoyanchev
* @author Eddú Meléndez
* @author Rob Winch
* @since 4.3
*/
public class ForwardedHeaderFilter extends OncePerRequestFilter {
private static final Set<String> FORWARDED_HEADER_NAMES =
Collections.newSetFromMap(new LinkedCaseInsensitiveMap<>(5, Locale.ENGLISH));
static {
FORWARDED_HEADER_NAMES.add("Forwarded");
FORWARDED_HEADER_NAMES.add("X-Forwarded-Host");
FORWARDED_HEADER_NAMES.add("X-Forwarded-Port");
FORWARDED_HEADER_NAMES.add("X-Forwarded-Proto");
FORWARDED_HEADER_NAMES.add("X-Forwarded-Prefix");
}
private final UrlPathHelper pathHelper;
public ForwardedHeaderFilter() {
this.pathHelper = new UrlPathHelper();
this.pathHelper.setUrlDecode(false);
this.pathHelper.setRemoveSemicolonContent(false);
}
@Override
protected boolean shouldNotFilter(HttpServletRequest request) throws ServletException {
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
if (FORWARDED_HEADER_NAMES.contains(name)) {
return false;
}
}
return true;
}
@Override
protected boolean shouldNotFilterAsyncDispatch() {
return false;
}
@Override
protected boolean shouldNotFilterErrorDispatch() {
return false;
}
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response,
FilterChain filterChain) throws ServletException, IOException {
ForwardedHeaderRequestWrapper wrappedRequest = new ForwardedHeaderRequestWrapper(request, this.pathHelper);
ForwardedHeaderResponseWrapper wrappedResponse = new ForwardedHeaderResponseWrapper(response, wrappedRequest);
filterChain.doFilter(wrappedRequest, wrappedResponse);
}
private static class ForwardedHeaderRequestWrapper extends HttpServletRequestWrapper {
private final String scheme;
private final boolean secure;
private final String host;
private final int port;
private final String contextPath;
private final String requestUri;
private final String requestUrl;
private final Map<String, List<String>> headers;
public ForwardedHeaderRequestWrapper(HttpServletRequest request, UrlPathHelper pathHelper) {
super(request);
HttpRequest httpRequest = new ServletServerHttpRequest(request);
UriComponents uriComponents = UriComponentsBuilder.fromHttpRequest(httpRequest).build();
int port = uriComponents.getPort();
this.scheme = uriComponents.getScheme();
this.secure = "https".equals(scheme);
this.host = uriComponents.getHost();
this.port = (port == -1 ? (this.secure ? 443 : 80) : port);
String prefix = getForwardedPrefix(request);
this.contextPath = (prefix != null ? prefix : request.getContextPath());
this.requestUri = this.contextPath + pathHelper.getPathWithinApplication(request);
this.requestUrl = this.scheme + "://" + this.host + (port == -1 ? "" : ":" + port) + this.requestUri;
this.headers = initHeaders(request);
}
private static String getForwardedPrefix(HttpServletRequest request) {
String prefix = null;
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
if ("X-Forwarded-Prefix".equalsIgnoreCase(name)) {
prefix = request.getHeader(name);
}
}
if (prefix != null) {
while (prefix.endsWith("/")) {
prefix = prefix.substring(0, prefix.length() - 1);
}
}
return prefix;
}
/**
* Copy the headers excluding any {@link #FORWARDED_HEADER_NAMES}.
*/
private static Map<String, List<String>> initHeaders(HttpServletRequest request) {
Map<String, List<String>> headers = new LinkedCaseInsensitiveMap<>(Locale.ENGLISH);
Enumeration<String> names = request.getHeaderNames();
while (names.hasMoreElements()) {
String name = names.nextElement();
if (!FORWARDED_HEADER_NAMES.contains(name)) {
headers.put(name, Collections.list(request.getHeaders(name)));
}
}
return headers;
}
@Override
public String getScheme() {
return this.scheme;
}
@Override
public String getServerName() {
return this.host;
}
@Override
public int getServerPort() {
return this.port;
}
@Override
public boolean isSecure() {
return this.secure;
}
@Override
public String getContextPath() {
return this.contextPath;
}
@Override
public String getRequestURI() {
return this.requestUri;
}
@Override
public StringBuffer getRequestURL() {
return new StringBuffer(this.requestUrl);
}
// Override header accessors to not expose forwarded headers
@Override
public String getHeader(String name) {
List<String> value = this.headers.get(name);
return (CollectionUtils.isEmpty(value) ? null : value.get(0));
}
@Override
public Enumeration<String> getHeaders(String name) {
List<String> value = this.headers.get(name);
return (Collections.enumeration(value != null ? value : Collections.emptySet()));
}
@Override
public Enumeration<String> getHeaderNames() {
return Collections.enumeration(this.headers.keySet());
}
}
private static class ForwardedHeaderResponseWrapper extends HttpServletResponseWrapper {
private static final String FOLDER_SEPARATOR = "/";
private final HttpServletRequest request;
public ForwardedHeaderResponseWrapper(HttpServletResponse response, HttpServletRequest request) {
super(response);
this.request = request;
}
@Override
public void sendRedirect(String location) throws IOException {
UriComponentsBuilder builder = UriComponentsBuilder.fromUriString(location);
// Absolute location
if (builder.build().getScheme() != null) {
super.sendRedirect(location);
return;
}
// Network-path reference
if (location.startsWith("//")) {
String scheme = this.request.getScheme();
super.sendRedirect(builder.scheme(scheme).toUriString());
return;
}
// Relative to Servlet container root or to current request
String path = (location.startsWith(FOLDER_SEPARATOR) ? location :
StringUtils.applyRelativePath(this.request.getRequestURI(), location));
String result = UriComponentsBuilder
.fromHttpRequest(new ServletServerHttpRequest(this.request))
.replacePath(path)
.build().normalize().toUriString();
super.sendRedirect(result);
}
}
}