/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.catalina.valves.rewrite;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringReader;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import jakarta.servlet.ServletException;
import jakarta.servlet.http.Cookie;
import jakarta.servlet.http.HttpServletResponse;

import org.apache.catalina.Container;
import org.apache.catalina.Context;
import org.apache.catalina.Lifecycle;
import org.apache.catalina.LifecycleException;
import org.apache.catalina.Pipeline;
import org.apache.catalina.connector.Connector;
import org.apache.catalina.connector.Request;
import org.apache.catalina.connector.Response;
import org.apache.catalina.util.URLEncoder;
import org.apache.catalina.valves.ValveBase;
import org.apache.juli.logging.LogFactory;
import org.apache.tomcat.util.buf.CharChunk;
import org.apache.tomcat.util.buf.MessageBytes;
import org.apache.tomcat.util.buf.UDecoder;
import org.apache.tomcat.util.buf.UriUtil;
import org.apache.tomcat.util.file.ConfigFileLoader;
import org.apache.tomcat.util.file.ConfigurationSource;
import org.apache.tomcat.util.http.RequestUtil;

Note: Extra caution should be used when adding a Rewrite Rule. When
specifying a regex to match for in a Rewrite Rule, certain regex could allow
an attacker to DoS your server, as Java's regex parsing is vulnerable to
"catastrophic backtracking" (also known as "Regular expression Denial of
Service", or ReDoS). There are some open source tools to help detect
vulnerable regex, though in general it is a hard problem. A good defence is
to use a regex debugger on your desired regex, and read more on the subject
of catastrophic backtracking.
See Also:
OWASP
 *      ReDoS/**
 * Note: Extra caution should be used when adding a Rewrite Rule. When
 * specifying a regex to match for in a Rewrite Rule, certain regex could allow
 * an attacker to DoS your server, as Java's regex parsing is vulnerable to
 * "catastrophic backtracking" (also known as "Regular expression Denial of
 * Service", or ReDoS). There are some open source tools to help detect
 * vulnerable regex, though in general it is a hard problem. A good defence is
 * to use a regex debugger on your desired regex, and read more on the subject
 * of catastrophic backtracking.
 *
 * @see <a href=
 *      "https://www.owasp.org/index.php/Regular_expression_Denial_of_Service_-_ReDoS">OWASP
 *      ReDoS</a>
 */
public class RewriteValve extends ValveBase {

    
The rewrite rules that the valve will use.
/**
     * The rewrite rules that the valve will use.
     */
    protected RewriteRule[] rules = null;


    
If rewriting occurs, the whole request will be processed again.
/**
     * If rewriting occurs, the whole request will be processed again.
     */
    protected ThreadLocal<Boolean> invoked = new ThreadLocal<>();


    
Relative path to the configuration file.
Note: If the valve's container is a context, this will be relative to
/WEB-INF/.
/**
     * Relative path to the configuration file.
     * Note: If the valve's container is a context, this will be relative to
     * /WEB-INF/.
     */
    protected String resourcePath = "rewrite.config";


    
Will be set to true if the valve is associated with a context.
/**
     * Will be set to true if the valve is associated with a context.
     */
    protected boolean context = false;


    
enabled this component
/**
     * enabled this component
     */
    protected boolean enabled = true;

    
Maps to be used by the rules.
/**
     * Maps to be used by the rules.
     */
    protected Map<String, RewriteMap> maps = new Hashtable<>();


    
Maps configuration.
/**
     * Maps configuration.
     */
    protected ArrayList<String> mapsConfiguration = new ArrayList<>();


    public RewriteValve() {
        super(true);
    }


    public boolean getEnabled() {
        return enabled;
    }

    public void setEnabled(boolean enabled) {
        this.enabled = enabled;
    }


    @Override
    protected void initInternal() throws LifecycleException {
        super.initInternal();
        containerLog = LogFactory.getLog(getContainer().getLogName() + ".rewrite");
    }


    @Override
    protected synchronized void startInternal() throws LifecycleException {

        super.startInternal();

        InputStream is = null;

        // Process configuration file for this valve
        if (getContainer() instanceof Context) {
            context = true;
            is = ((Context) getContainer()).getServletContext()
                .getResourceAsStream("/WEB-INF/" + resourcePath);
            if (containerLog.isDebugEnabled()) {
                if (is == null) {
                    containerLog.debug("No configuration resource found: /WEB-INF/" + resourcePath);
                } else {
                    containerLog.debug("Read configuration from: /WEB-INF/" + resourcePath);
                }
            }
        } else {
            String resourceName = Container.getConfigPath(getContainer(), resourcePath);
            try {
                ConfigurationSource.Resource resource = ConfigFileLoader.getSource().getResource(resourceName);
                is = resource.getInputStream();
            } catch (IOException e) {
                if (containerLog.isDebugEnabled()) {
                    containerLog.debug("No configuration resource found: " + resourceName, e);
                }
            }
        }

        if (is == null) {
            // Will use management operations to configure the valve dynamically
            return;
        }

        try (InputStreamReader isr = new InputStreamReader(is, StandardCharsets.UTF_8);
                BufferedReader reader = new BufferedReader(isr)) {
            parse(reader);
        } catch (IOException ioe) {
            containerLog.error(sm.getString("rewriteValve.closeError"), ioe);
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                containerLog.error(sm.getString("rewriteValve.closeError"), e);
            }
        }

    }

    public void setConfiguration(String configuration)
        throws Exception {
        if (containerLog == null) {
            containerLog = LogFactory.getLog(getContainer().getLogName() + ".rewrite");
        }
        maps.clear();
        parse(new BufferedReader(new StringReader(configuration)));
    }

    public String getConfiguration() {
        StringBuilder buffer = new StringBuilder();
        for (String mapConfiguration : mapsConfiguration) {
            buffer.append(mapConfiguration).append("\r\n");
        }
        if (mapsConfiguration.size() > 0) {
            buffer.append("\r\n");
        }
        for (RewriteRule rule : rules) {
            for (int j = 0; j < rule.getConditions().length; j++) {
                buffer.append(rule.getConditions()[j].toString()).append("\r\n");
            }
            buffer.append(rule.toString()).append("\r\n").append("\r\n");
        }
        return buffer.toString();
    }

    protected void parse(BufferedReader reader) throws LifecycleException {
        List<RewriteRule> rules = new ArrayList<>();
        List<RewriteCond> conditions = new ArrayList<>();
        while (true) {
            try {
                String line = reader.readLine();
                if (line == null) {
                    break;
                }
                Object result = parse(line);
                if (result instanceof RewriteRule) {
                    RewriteRule rule = (RewriteRule) result;
                    if (containerLog.isDebugEnabled()) {
                        containerLog.debug("Add rule with pattern " + rule.getPatternString()
                                + " and substitution " + rule.getSubstitutionString());
                    }
                    for (int i = (conditions.size() - 1); i > 0; i--) {
                        if (conditions.get(i - 1).isOrnext()) {
                            conditions.get(i).setOrnext(true);
                        }
                    }
                    for (RewriteCond condition : conditions) {
                        if (containerLog.isDebugEnabled()) {
                            RewriteCond cond = condition;
                            containerLog.debug("Add condition " + cond.getCondPattern()
                                    + " test " + cond.getTestString() + " to rule with pattern "
                                    + rule.getPatternString() + " and substitution "
                                    + rule.getSubstitutionString() + (cond.isOrnext() ? " [OR]" : "")
                                    + (cond.isNocase() ? " [NC]" : ""));
                        }
                        rule.addCondition(condition);
                    }
                    conditions.clear();
                    rules.add(rule);
                } else if (result instanceof RewriteCond) {
                    conditions.add((RewriteCond) result);
                } else if (result instanceof Object[]) {
                    String mapName = (String) ((Object[]) result)[0];
                    RewriteMap map = (RewriteMap) ((Object[]) result)[1];
                    maps.put(mapName, map);
                    // Keep the original configuration line as it is not possible to get
                    // the parameters back without an API change
                    mapsConfiguration.add(line);
                    if (map instanceof Lifecycle) {
                        ((Lifecycle) map).start();
                    }
                }
            } catch (IOException e) {
                containerLog.error(sm.getString("rewriteValve.readError"), e);
            }
        }
        this.rules = rules.toArray(new RewriteRule[0]);

        // Finish parsing the rules
        for (RewriteRule rule : this.rules) {
            rule.parse(maps);
        }
    }

    @Override
    protected synchronized void stopInternal() throws LifecycleException {
        super.stopInternal();
        for (RewriteMap map : maps.values()) {
            if (map instanceof Lifecycle) {
                ((Lifecycle) map).stop();
            }
        }
        maps.clear();
        rules = null;
    }


    @Override
    public void invoke(Request request, Response response)
        throws IOException, ServletException {

        if (!getEnabled() || rules == null || rules.length == 0) {
            getNext().invoke(request, response);
            return;
        }

        if (Boolean.TRUE.equals(invoked.get())) {
            try {
                getNext().invoke(request, response);
            } finally {
                invoked.set(null);
            }
            return;
        }

        try {

            Resolver resolver = new ResolverImpl(request);

            invoked.set(Boolean.TRUE);

            // As long as MB isn't a char sequence or affiliated, this has to be
            // converted to a string
            Charset uriCharset = request.getConnector().getURICharset();
            String originalQueryStringEncoded = request.getQueryString();
            MessageBytes urlMB =
                    context ? request.getRequestPathMB() : request.getDecodedRequestURIMB();
            urlMB.toChars();
            CharSequence urlDecoded = urlMB.getCharChunk();
            CharSequence host = request.getServerName();
            boolean rewritten = false;
            boolean done = false;
            boolean qsa = false;
            boolean qsd = false;
            for (int i = 0; i < rules.length; i++) {
                RewriteRule rule = rules[i];
                CharSequence test = (rule.isHost()) ? host : urlDecoded;
                CharSequence newtest = rule.evaluate(test, resolver);
                if (newtest != null && !test.equals(newtest.toString())) {
                    if (containerLog.isDebugEnabled()) {
                        containerLog.debug("Rewrote " + test + " as " + newtest
                                + " with rule pattern " + rule.getPatternString());
                    }
                    if (rule.isHost()) {
                        host = newtest;
                    } else {
                        urlDecoded = newtest;
                    }
                    rewritten = true;
                }

                // Check QSA before the final reply
                if (!qsa && newtest != null && rule.isQsappend()) {
                    qsa = true;
                }

                if (!qsa && newtest != null && rule.isQsdiscard()) {
                    qsd = true;
                }

                // Final reply

                // - forbidden
                if (rule.isForbidden() && newtest != null) {
                    response.sendError(HttpServletResponse.SC_FORBIDDEN);
                    done = true;
                    break;
                }
                // - gone
                if (rule.isGone() && newtest != null) {
                    response.sendError(HttpServletResponse.SC_GONE);
                    done = true;
                    break;
                }

                // - redirect (code)
                if (rule.isRedirect() && newtest != null) {
                    // Append the query string to the url if there is one and it
                    // hasn't been rewritten
                    String urlStringDecoded = urlDecoded.toString();
                    int index = urlStringDecoded.indexOf("?");
                    String rewrittenQueryStringDecoded;
                    if (index == -1) {
                        rewrittenQueryStringDecoded = null;
                    } else {
                        rewrittenQueryStringDecoded = urlStringDecoded.substring(index + 1);
                        urlStringDecoded = urlStringDecoded.substring(0, index);
                    }

                    StringBuilder urlStringEncoded =
                            new StringBuilder(URLEncoder.DEFAULT.encode(urlStringDecoded, uriCharset));
                    if (!qsd && originalQueryStringEncoded != null
                            && originalQueryStringEncoded.length() > 0) {
                        if (rewrittenQueryStringDecoded == null) {
                            urlStringEncoded.append('?');
                            urlStringEncoded.append(originalQueryStringEncoded);
                        } else {
                            if (qsa) {
                                // if qsa is specified append the query
                                urlStringEncoded.append('?');
                                urlStringEncoded.append(URLEncoder.QUERY.encode(
                                        rewrittenQueryStringDecoded, uriCharset));
                                urlStringEncoded.append('&');
                                urlStringEncoded.append(originalQueryStringEncoded);
                            } else if (index == urlStringEncoded.length() - 1) {
                                // if the ? is the last character delete it, its only purpose was to
                                // prevent the rewrite module from appending the query string
                                urlStringEncoded.deleteCharAt(index);
                            } else {
                                urlStringEncoded.append('?');
                                urlStringEncoded.append(URLEncoder.QUERY.encode(
                                        rewrittenQueryStringDecoded, uriCharset));
                            }
                        }
                    } else if (rewrittenQueryStringDecoded != null) {
                        urlStringEncoded.append('?');
                        urlStringEncoded.append(
                                URLEncoder.QUERY.encode(rewrittenQueryStringDecoded, uriCharset));
                    }

                    // Insert the context if
                    // 1. this valve is associated with a context
                    // 2. the url starts with a leading slash
                    // 3. the url isn't absolute
                    if (context && urlStringEncoded.charAt(0) == '/' &&
                            !UriUtil.hasScheme(urlStringEncoded)) {
                        urlStringEncoded.insert(0, request.getContext().getEncodedPath());
                    }
                    if (rule.isNoescape()) {
                        response.sendRedirect(
                                UDecoder.URLDecode(urlStringEncoded.toString(), uriCharset));
                    } else {
                        response.sendRedirect(urlStringEncoded.toString());
                    }
                    response.setStatus(rule.getRedirectCode());
                    done = true;
                    break;
                }

                // Reply modification

                // - cookie
                if (rule.isCookie() && newtest != null) {
                    Cookie cookie = new Cookie(rule.getCookieName(),
                            rule.getCookieResult());
                    cookie.setDomain(rule.getCookieDomain());
                    cookie.setMaxAge(rule.getCookieLifetime());
                    cookie.setPath(rule.getCookiePath());
                    cookie.setSecure(rule.isCookieSecure());
                    cookie.setHttpOnly(rule.isCookieHttpOnly());
                    response.addCookie(cookie);
                }
                // - env (note: this sets a request attribute)
                if (rule.isEnv() && newtest != null) {
                    for (int j = 0; j < rule.getEnvSize(); j++) {
                        request.setAttribute(rule.getEnvName(j), rule.getEnvResult(j));
                    }
                }
                // - content type (note: this will not force the content type, use a filter
                //   to do that)
                if (rule.isType() && newtest != null) {
                    request.setContentType(rule.getTypeValue());
                }

                // Control flow processing

                // - chain (skip remaining chained rules if this one does not match)
                if (rule.isChain() && newtest == null) {
                    for (int j = i; j < rules.length; j++) {
                        if (!rules[j].isChain()) {
                            i = j;
                            break;
                        }
                    }
                    continue;
                }
                // - last (stop rewriting here)
                if (rule.isLast() && newtest != null) {
                    break;
                }
                // - next (redo again)
                if (rule.isNext() && newtest != null) {
                    i = 0;
                    continue;
                }
                // - skip (n rules)
                if (newtest != null) {
                    i += rule.getSkip();
                }

            }

            if (rewritten) {
                if (!done) {
                    // See if we need to replace the query string
                    String urlStringDecoded = urlDecoded.toString();
                    String queryStringDecoded = null;
                    int queryIndex = urlStringDecoded.indexOf('?');
                    if (queryIndex != -1) {
                        queryStringDecoded = urlStringDecoded.substring(queryIndex+1);
                        urlStringDecoded = urlStringDecoded.substring(0, queryIndex);
                    }
                    // Save the current context path before re-writing starts
                    String contextPath = null;
                    if (context) {
                        contextPath = request.getContextPath();
                    }
                    // Populated the encoded (i.e. undecoded) requestURI
                    request.getCoyoteRequest().requestURI().setString(null);
                    CharChunk chunk = request.getCoyoteRequest().requestURI().getCharChunk();
                    chunk.recycle();
                    if (context) {
                        // This is neither decoded nor normalized
                        chunk.append(contextPath);
                    }
                    chunk.append(URLEncoder.DEFAULT.encode(urlStringDecoded, uriCharset));
                    request.getCoyoteRequest().requestURI().toChars();
                    // Decoded and normalized URI
                    // Rewriting may have denormalized the URL
                    urlStringDecoded = RequestUtil.normalize(urlStringDecoded);
                    request.getCoyoteRequest().decodedURI().setString(null);
                    chunk = request.getCoyoteRequest().decodedURI().getCharChunk();
                    chunk.recycle();
                    if (context) {
                        // This is decoded and normalized
                        chunk.append(request.getServletContext().getContextPath());
                    }
                    chunk.append(urlStringDecoded);
                    request.getCoyoteRequest().decodedURI().toChars();
                    // Set the new Query if there is one
                    if (queryStringDecoded != null) {
                        request.getCoyoteRequest().queryString().setString(null);
                        chunk = request.getCoyoteRequest().queryString().getCharChunk();
                        chunk.recycle();
                        chunk.append(URLEncoder.QUERY.encode(queryStringDecoded, uriCharset));
                        if (qsa && originalQueryStringEncoded != null &&
                                originalQueryStringEncoded.length() > 0) {
                            chunk.append('&');
                            chunk.append(originalQueryStringEncoded);
                        }
                        if (!chunk.isNull()) {
                            request.getCoyoteRequest().queryString().toChars();
                        }
                    }
                    // Set the new host if it changed
                    if (!host.equals(request.getServerName())) {
                        request.getCoyoteRequest().serverName().setString(null);
                        chunk = request.getCoyoteRequest().serverName().getCharChunk();
                        chunk.recycle();
                        chunk.append(host.toString());
                        request.getCoyoteRequest().serverName().toChars();
                    }
                    request.getMappingData().recycle();
                    // Reinvoke the whole request recursively
                    Connector connector = request.getConnector();
                    try {
                        if (!connector.getProtocolHandler().getAdapter().prepare(
                                request.getCoyoteRequest(), response.getCoyoteResponse())) {
                            return;
                        }
                    } catch (Exception e) {
                        // This doesn't actually happen in the Catalina adapter implementation
                    }
                    Pipeline pipeline = connector.getService().getContainer().getPipeline();
                    request.setAsyncSupported(pipeline.isAsyncSupported());
                    pipeline.getFirst().invoke(request, response);
                }
            } else {
                getNext().invoke(request, response);
            }

        } finally {
            invoked.set(null);
        }

    }


    
This factory method will parse a line formed like:
Example:
 RewriteCond %{REMOTE_HOST}  ^host1.*  [OR]
Params:
line – A line from the rewrite configuration
Returns:
The condition, rule or map resulting from parsing the line/**
     * This factory method will parse a line formed like:
     *
     * Example:
     *  RewriteCond %{REMOTE_HOST}  ^host1.*  [OR]
     *
     * @param line A line from the rewrite configuration
     * @return The condition, rule or map resulting from parsing the line
     */
    public static Object parse(String line) {
        QuotedStringTokenizer tokenizer = new QuotedStringTokenizer(line);
        if (tokenizer.hasMoreTokens()) {
            String token = tokenizer.nextToken();
            if (token.equals("RewriteCond")) {
                // RewriteCond TestString CondPattern [Flags]
                RewriteCond condition = new RewriteCond();
                if (tokenizer.countTokens() < 2) {
                    throw new IllegalArgumentException(sm.getString("rewriteValve.invalidLine", line));
                }
                condition.setTestString(tokenizer.nextToken());
                condition.setCondPattern(tokenizer.nextToken());
                if (tokenizer.hasMoreTokens()) {
                    String flags = tokenizer.nextToken();
                    condition.setFlagsString(flags);
                    if (flags.startsWith("[") && flags.endsWith("]")) {
                        flags = flags.substring(1, flags.length() - 1);
                    }
                    StringTokenizer flagsTokenizer = new StringTokenizer(flags, ",");
                    while (flagsTokenizer.hasMoreElements()) {
                        parseCondFlag(line, condition, flagsTokenizer.nextToken());
                    }
                }
                return condition;
            } else if (token.equals("RewriteRule")) {
                // RewriteRule Pattern Substitution [Flags]
                RewriteRule rule = new RewriteRule();
                if (tokenizer.countTokens() < 2) {
                    throw new IllegalArgumentException(sm.getString("rewriteValve.invalidLine", line));
                }
                rule.setPatternString(tokenizer.nextToken());
                rule.setSubstitutionString(tokenizer.nextToken());
                if (tokenizer.hasMoreTokens()) {
                    String flags = tokenizer.nextToken();
                    rule.setFlagsString(flags);
                    if (flags.startsWith("[") && flags.endsWith("]")) {
                        flags = flags.substring(1, flags.length() - 1);
                    }
                    StringTokenizer flagsTokenizer = new StringTokenizer(flags, ",");
                    while (flagsTokenizer.hasMoreElements()) {
                        parseRuleFlag(line, rule, flagsTokenizer.nextToken());
                    }
                }
                return rule;
            } else if (token.equals("RewriteMap")) {
                // RewriteMap name rewriteMapClassName whateverOptionalParameterInWhateverFormat
                // FIXME: Possibly implement more special maps from https://httpd.apache.org/docs/2.4/rewrite/rewritemap.html
                if (tokenizer.countTokens() < 2) {
                    throw new IllegalArgumentException(sm.getString("rewriteValve.invalidLine", line));
                }
                String name = tokenizer.nextToken();
                String rewriteMapClassName = tokenizer.nextToken();
                RewriteMap map = null;
                if (rewriteMapClassName.startsWith("int:")) {
                    map = InternalRewriteMap.toMap(rewriteMapClassName.substring("int:".length()));
                } else if (rewriteMapClassName.startsWith("prg:")) {
                    rewriteMapClassName = rewriteMapClassName.substring("prg:".length());
                }
                if (map == null) {
                    try {
                        map = (RewriteMap) (Class.forName(
                                rewriteMapClassName).getConstructor().newInstance());
                    } catch (Exception e) {
                        throw new IllegalArgumentException(sm.getString("rewriteValve.invalidMapClassName", line));
                    }
                }
                if (tokenizer.hasMoreTokens()) {
                    if (tokenizer.countTokens() == 1) {
                        map.setParameters(tokenizer.nextToken());
                    } else {
                        List<String> params = new ArrayList<>();
                        while (tokenizer.hasMoreTokens()) {
                            params.add(tokenizer.nextToken());
                        }
                        map.setParameters(params.toArray(new String[0]));
                    }
                }
                return new Object[] { name, map };
            } else if (token.startsWith("#")) {
                // it's a comment, ignore it
            } else {
                throw new IllegalArgumentException(sm.getString("rewriteValve.invalidLine", line));
            }
        }
        return null;
    }


    
Parser for RewriteCond flags.
Params:
line – The configuration line being parsed
condition – The current condition
flag – The flag/**
     * Parser for RewriteCond flags.
     * @param line The configuration line being parsed
     * @param condition The current condition
     * @param flag The flag
     */
    protected static void parseCondFlag(String line, RewriteCond condition, String flag) {
        if (flag.equals("NC") || flag.equals("nocase")) {
            condition.setNocase(true);
        } else if (flag.equals("OR") || flag.equals("ornext")) {
            condition.setOrnext(true);
        } else {
            throw new IllegalArgumentException(sm.getString("rewriteValve.invalidFlags", line, flag));
        }
    }


    
Parser for RewriteRule flags.
Params:
line – The configuration line being parsed
rule – The current rule
flag – The flag/**
     * Parser for RewriteRule flags.
     * @param line The configuration line being parsed
     * @param rule The current rule
     * @param flag The flag
     */
    protected static void parseRuleFlag(String line, RewriteRule rule, String flag) {
        if (flag.equals("B")) {
            rule.setEscapeBackReferences(true);
        } else if (flag.equals("chain") || flag.equals("C")) {
            rule.setChain(true);
        } else if (flag.startsWith("cookie=") || flag.startsWith("CO=")) {
            rule.setCookie(true);
            if (flag.startsWith("cookie")) {
                flag = flag.substring("cookie=".length());
            } else if (flag.startsWith("CO=")) {
                flag = flag.substring("CO=".length());
            }
            StringTokenizer tokenizer = new StringTokenizer(flag, ":");
            if (tokenizer.countTokens() < 2) {
                throw new IllegalArgumentException(sm.getString("rewriteValve.invalidFlags", line, flag));
            }
            rule.setCookieName(tokenizer.nextToken());
            rule.setCookieValue(tokenizer.nextToken());
            if (tokenizer.hasMoreTokens()) {
                rule.setCookieDomain(tokenizer.nextToken());
            }
            if (tokenizer.hasMoreTokens()) {
                try {
                    rule.setCookieLifetime(Integer.parseInt(tokenizer.nextToken()));
                } catch (NumberFormatException e) {
                    throw new IllegalArgumentException(sm.getString("rewriteValve.invalidFlags", line, flag), e);
                }
            }
            if (tokenizer.hasMoreTokens()) {
                rule.setCookiePath(tokenizer.nextToken());
            }
            if (tokenizer.hasMoreTokens()) {
                rule.setCookieSecure(Boolean.parseBoolean(tokenizer.nextToken()));
            }
            if (tokenizer.hasMoreTokens()) {
                rule.setCookieHttpOnly(Boolean.parseBoolean(tokenizer.nextToken()));
            }
        } else if (flag.startsWith("env=") || flag.startsWith("E=")) {
            rule.setEnv(true);
            if (flag.startsWith("env=")) {
                flag = flag.substring("env=".length());
            } else if (flag.startsWith("E=")) {
                flag = flag.substring("E=".length());
            }
            int pos = flag.indexOf(':');
            if (pos == -1 || (pos + 1) == flag.length()) {
                throw new IllegalArgumentException(sm.getString("rewriteValve.invalidFlags", line, flag));
            }
            rule.addEnvName(flag.substring(0, pos));
            rule.addEnvValue(flag.substring(pos + 1));
        } else if (flag.startsWith("forbidden") || flag.startsWith("F")) {
            rule.setForbidden(true);
        } else if (flag.startsWith("gone") || flag.startsWith("G")) {
            rule.setGone(true);
        } else if (flag.startsWith("host") || flag.startsWith("H")) {
            rule.setHost(true);
        } else if (flag.startsWith("last") || flag.startsWith("L")) {
            rule.setLast(true);
        } else if (flag.startsWith("nocase") || flag.startsWith("NC")) {
            rule.setNocase(true);
        } else if (flag.startsWith("noescape") || flag.startsWith("NE")) {
            rule.setNoescape(true);
        } else if (flag.startsWith("next") || flag.startsWith("N")) {
            rule.setNext(true);
        // Note: Proxy is not supported as Tomcat does not have proxy
        //       capabilities
        } else if (flag.startsWith("qsappend") || flag.startsWith("QSA")) {
            rule.setQsappend(true);
        } else if (flag.startsWith("qsdiscard") || flag.startsWith("QSD")) {
            rule.setQsdiscard(true);
        } else if (flag.startsWith("redirect") || flag.startsWith("R")) {
            rule.setRedirect(true);
            int redirectCode = HttpServletResponse.SC_FOUND;
            if (flag.startsWith("redirect=") || flag.startsWith("R=")) {
                if (flag.startsWith("redirect=")) {
                    flag = flag.substring("redirect=".length());
                } else if (flag.startsWith("R=")) {
                    flag = flag.substring("R=".length());
                }
                switch(flag) {
                    case "temp":
                        redirectCode = HttpServletResponse.SC_FOUND;
                        break;
                    case "permanent":
                        redirectCode = HttpServletResponse.SC_MOVED_PERMANENTLY;
                        break;
                    case "seeother":
                        redirectCode = HttpServletResponse.SC_SEE_OTHER;
                        break;
                    default:
                        redirectCode = Integer.parseInt(flag);
                        break;
                }
            }
            rule.setRedirectCode(redirectCode);
        } else if (flag.startsWith("skip") || flag.startsWith("S")) {
            if (flag.startsWith("skip=")) {
                flag = flag.substring("skip=".length());
            } else if (flag.startsWith("S=")) {
                flag = flag.substring("S=".length());
            }
            rule.setSkip(Integer.parseInt(flag));
        } else if (flag.startsWith("type") || flag.startsWith("T")) {
            if (flag.startsWith("type=")) {
                flag = flag.substring("type=".length());
            } else if (flag.startsWith("T=")) {
                flag = flag.substring("T=".length());
            }
            rule.setType(true);
            rule.setTypeValue(flag);
        } else {
            throw new IllegalArgumentException(sm.getString("rewriteValve.invalidFlags", line, flag));
        }
    }
}