/*
* Copyright (c) 2002-2012 Alibaba Group Holding Limited.
* All rights reserved.
*
* 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 com.alibaba.citrus.service.requestcontext.rewrite.impl;
import java.util.regex.MatchResult;
import javax.servlet.http.HttpServletRequest;
import com.alibaba.citrus.service.requestcontext.parser.ParserRequestContext;
import com.alibaba.citrus.service.requestcontext.util.RequestContextUtil;
import com.alibaba.citrus.util.regex.MatchResultSubstitution;
/**
* 和rewrite相关的工具类。
*
* @author Michael Zhou
*/
public class RewriteUtil {
public static boolean isFullURL(String path) {
return path.matches("^\\w+:.*");
}
public static MatchResultSubstitution getMatchResultSubstitution(MatchResult ruleMatchResult,
MatchResult conditionMatchResult) {
return new MatchResultSubstitution("$%", ruleMatchResult, conditionMatchResult);
}
public static String getSubstitutedTestString(String testString, MatchResult ruleMatchResult,
MatchResult conditionMatchResult, HttpServletRequest request) {
testString = eval(testString, request);
return getMatchResultSubstitution(ruleMatchResult, conditionMatchResult).substitute(testString);
}
protected static String eval(String expr, HttpServletRequest request) {
int length = expr.length();
int startIndex = expr.indexOf("%{");
// 如果表达式不包含%{}，则直接返回之。
if (startIndex < 0) {
return expr;
}
int endIndex = expr.indexOf("}", startIndex + 2);
if (endIndex < 0) {
return expr;
}
// 创建复合的表达式。
StringBuffer resultBuffer = new StringBuffer();
StringBuffer charBuffer = new StringBuffer();
StringBuffer varNameBuffer = new StringBuffer();
MAIN_LOOP:
for (int i = 0; i < length; ) {
char ch = expr.charAt(i);
switch (ch) {
case '%':
if (i + 1 < length) {
ch = expr.charAt(++i);
switch (ch) {
case '%':
charBuffer.append(ch);
break;
case '{':
if (charBuffer.length() > 0) {
resultBuffer.append(charBuffer);
charBuffer.setLength(0);
}
if (i + 1 < length) {
++i;
while (i < length) {
ch = expr.charAt(i);
switch (ch) {
case '}':
String varName = varNameBuffer.toString();
String varNameExpanded = expandAndEscape(varName, request);
if (varNameExpanded == null) {
resultBuffer.append("\\%{").append(varName).append("}");
} else {
resultBuffer.append(varNameExpanded);
}
varNameBuffer.setLength(0);
++i;
continue MAIN_LOOP;
default:
varNameBuffer.append(ch);
++i;
}
}
if (varNameBuffer.length() > 0) {
resultBuffer.append("%{").append(varNameBuffer);
}
}
break;
default:
charBuffer.append('%').append(ch);
}
} else {
charBuffer.append(ch);
}
break;
default:
charBuffer.append(ch);
}
i++;
}
if (charBuffer.length() > 0) {
resultBuffer.append(charBuffer);
}
return resultBuffer.toString();
}
/**
* 展开变量，并对其中的特殊字符进行处理，避免其被解析。
*
* @return 注意，如果返回null，表示按原样显示，例如：%{XYZ}
*/
private static String expandAndEscape(String varName, HttpServletRequest request) {
String value = expand(varName, request);
if (value != null) {
int length = value.length();
StringBuilder buf = new StringBuilder(length + 10);
boolean changed = false;
for (int i = 0; i < length; i++) {
char ch = value.charAt(i);
switch (ch) {
case '\\':
buf.append("\\\\");
changed = true;
break;
case '$':
buf.append("\\$");
changed = true;
break;
case '%':
buf.append("\\%");
changed = true;
break;
default:
buf.append(ch);
}
}
if (changed) {
value = buf.toString();
}
}
return value;
}
/**
* 展开变量。
*
* @return 注意，如果返回null，表示按原样显示，例如：%{XYZ}
*/
private static String expand(String varName, HttpServletRequest request) {
boolean valid = true;
String result;
// =====================================================
// Client side of the IP connection
// =====================================================
if ("REMOTE_HOST".equals(varName)) {
result = request.getRemoteHost();
}
//
else if ("REMOTE_ADDR".equals(varName)) {
result = request.getRemoteAddr();
}
//
else if ("REMOTE_USER".equals(varName)) {
result = request.getRemoteUser();
}
//
else if ("REQUEST_METHOD".equals(varName)) {
result = request.getMethod();
}
//
else if ("QUERY_STRING".equals(varName)) {
if ("post".equalsIgnoreCase(request.getMethod())) {
ParserRequestContext parserRequestContext = RequestContextUtil.findRequestContext(request,
ParserRequestContext.class);
result = parserRequestContext.getParameters().toQueryString();
} else {
result = request.getQueryString();
}
}
//
else if (varName.startsWith("QUERY:")) {
ParserRequestContext parserRequestContext = RequestContextUtil.findRequestContext(request,
ParserRequestContext.class);
result = parserRequestContext.getParameters().getString(varName.substring("QUERY:".length()).trim());
}
//
else if ("AUTH_TYPE".equals(varName)) {
result = request.getAuthType();
}
// =====================================================
// HTTP layer details extracted from HTTP headers
// =====================================================
else if ("SERVER_NAME".equals(varName)) {
result = request.getServerName();
}
//
else if ("SERVER_PORT".equals(varName)) {
result = String.valueOf(request.getServerPort());
}
//
else if ("SERVER_PROTOCOL".equals(varName)) {
result = request.getProtocol();
}
// =====================================================
// HTTP headers
// =====================================================
else if ("HTTP_USER_AGENT".equals(varName)) {
result = request.getHeader("User-Agent");
}
//
else if ("HTTP_REFERER".equals(varName)) {
result = request.getHeader("Referer");
}
//
else if ("HTTP_HOST".equals(varName)) {
result = request.getHeader("Host");
}
//
else if ("HTTP_ACCEPT".equals(varName)) {
result = request.getHeader("Accept");
}
//
else if ("HTTP_COOKIE".equals(varName)) {
result = request.getHeader("Cookie");
}
// =====================================================
// Others
// =====================================================
else if ("REQUEST_URI".equals(varName)) {
result = request.getRequestURI();
} else {
result = null;
valid = false;
}
// 如果变量合法，但值为null，则返回""
if (valid && result == null) {
result = "";
}
return result;
}
}