/*
* 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 static com.alibaba.citrus.util.ArrayUtil.*;
import java.util.regex.MatchResult;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;
import javax.servlet.http.HttpServletRequest;
import com.alibaba.citrus.service.requestcontext.rewrite.RewriteSubstitutionHandler;
import com.alibaba.citrus.util.StringEscapeUtil;
import com.alibaba.citrus.util.StringUtil;
import com.alibaba.citrus.util.ToStringBuilder;
import com.alibaba.citrus.util.ToStringBuilder.MapBuilder;
import com.alibaba.citrus.util.regex.MatchResultSubstitution;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.InitializingBean;
/**
* 代表一个rewrite规则。
* <p>
* 每个rewrite规则被匹配后，就会再试着匹配所有的conditions（如果有的话）。假如conditions也被满足，
* 那么substitution就会被执行。
* </p>
*
* @author Michael Zhou
*/
public class RewriteRule implements InitializingBean {
private static final Logger log = LoggerFactory.getLogger(RewriteRule.class);
private String patternString;
private Pattern pattern;
private boolean negative;
private RewriteCondition[] conditions;
private RewriteSubstitution substitution;
private Object[] handlers;
public String getPattern() {
return patternString;
}
public void setPattern(String patternString) throws PatternSyntaxException {
this.patternString = StringUtil.trimToNull(patternString);
}
public void setConditions(RewriteCondition[] conditions) {
this.conditions = conditions;
}
public void setSubstitution(RewriteSubstitution substitution) {
this.substitution = substitution;
}
public void setHandlers(Object[] handlers) {
this.handlers = handlers;
}
public Object[] handlers() {
return handlers;
}
public void afterPropertiesSet() throws Exception {
// pattern
if (patternString == null || "!".equals(patternString)) {
throw new PatternSyntaxException("empty pattern", patternString, -1);
}
String realPattern;
if (patternString.startsWith("!")) {
negative = true;
realPattern = patternString.substring(1);
} else {
realPattern = patternString;
}
pattern = Pattern.compile(realPattern);
// conditions
if (conditions == null) {
conditions = new RewriteCondition[0];
}
// substitution
if (substitution == null) {
substitution = new RewriteSubstitution();
substitution.afterPropertiesSet();
}
// handlers
if (handlers == null) {
handlers = new RewriteSubstitutionHandler[0];
}
}
/**
* 试图匹配rule。
* <p>
* 如果匹配，则返回匹配结果。否则返回<code>null</code>表示不匹配。
* </p>
*/
public MatchResult match(String path) {
Matcher matcher = pattern.matcher(path);
boolean matched = matcher.find();
if (!negative && matched) {
if (log.isDebugEnabled()) {
log.debug("Testing \"{}\" with rule pattern: \"{}\", MATCHED", StringEscapeUtil.escapeJava(path),
StringEscapeUtil.escapeJava(patternString));
}
return matcher.toMatchResult();
}
if (negative && !matched) {
if (log.isDebugEnabled()) {
log.debug("Testing \"{}\" with rule pattern: \"{}\", MATCHED", StringEscapeUtil.escapeJava(path),
StringEscapeUtil.escapeJava(patternString));
}
return MatchResultSubstitution.EMPTY_MATCH_RESULT;
}
if (log.isTraceEnabled()) {
log.trace("Testing \"{}\" with rule pattern: \"{}\", MISMATCHED", StringEscapeUtil.escapeJava(path),
StringEscapeUtil.escapeJava(patternString));
}
return null;
}
public MatchResult matchConditions(MatchResult ruleMatchResult, HttpServletRequest request) {
MatchResult conditionMatchResult = MatchResultSubstitution.EMPTY_MATCH_RESULT;
if (!isEmptyArray(conditions)) {
int i = 0;
for (RewriteCondition condition : conditions) {
MatchResult result = condition.match(ruleMatchResult, conditionMatchResult, request);
// 判断ornext标记，但对最后一个condition忽略ornext标记，否则会得出错误结果。
boolean ornext = i < conditions.length - 1 && condition.getFlags().hasOR();
if (result == null) {
if (!ornext) {
conditionMatchResult = null;
break;
}
// 保持conditionMatchResult结果为最近的一次匹配
} else {
conditionMatchResult = result;
if (ornext) {
break;
}
}
i++;
}
}
return conditionMatchResult;
}
public RewriteSubstitution getSubstitution() {
return substitution;
}
@Override
public String toString() {
MapBuilder mb = new MapBuilder();
mb.append("pattern", patternString);
if (!isEmptyArray(conditions)) {
mb.append("conditions", conditions);
}
mb.append("substitution", substitution);
return new ToStringBuilder().append("RewriteRule").append(mb).toString();
}
}