condition.java

UrlRewriteFilter 是一个不错的URL转换工具

/**
 * Copyright (c) 2005-2007, Paul Tuckey
 * All rights reserved.
 * ====================================================================
 * Licensed under the BSD License. Text as follows.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials provided
 *     with the distribution.
 *   - Neither the name tuckey.org nor the names of its contributors
 *     may be used to endorse or promote products derived from this
 *     software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
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 */
package org.tuckey.web.filters.urlrewrite;

import org.tuckey.web.filters.urlrewrite.utils.Log;
import org.tuckey.web.filters.urlrewrite.utils.NumberUtils;
import org.tuckey.web.filters.urlrewrite.utils.RegexPattern;
import org.tuckey.web.filters.urlrewrite.utils.StringMatchingMatcher;
import org.tuckey.web.filters.urlrewrite.utils.StringMatchingPattern;
import org.tuckey.web.filters.urlrewrite.utils.StringMatchingPatternSyntaxException;
import org.tuckey.web.filters.urlrewrite.utils.StringUtils;
import org.tuckey.web.filters.urlrewrite.utils.WildcardPattern;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.util.Calendar;

/**
 * Conditions must be met when the filter is processing a url.
 *
 * @author Paul Tuckey
 * @version $Revision: 48 $ $Date: 2006-11-27 16:53:31 +1300 (Mon, 27 Nov 2006) $
 */
public class Condition extends TypeConverter {

    private static Log log = Log.getLog(Condition.class);

    /**
     * Should this expression be matched case sensitively.
     */
    private boolean caseSensitive = false;

    /**
     * Used to identify the condition.
     */
    private int id = 0;

    /**
     * Used to cache the pattern for faster execution.
     */
    private StringMatchingPattern pattern;

    /**
     * The name of the header etc.
     */
    private String name;

    /**
     * The operator that should be used to evaluate the condition.
     */
    private short operator;

    /**
     * Value of this condition if the type is header.
     */
    private String strValue;

    /**
     * Value of this condition if the type is port.
     */
    private long numericValue = 0;

    /**
     * What to do with the next rule, this will indicate "or" otherwise do "and".
     */
    private boolean processNextOr = false;

    private boolean valid = false;
    private boolean initialised = false;

    // Operators
    private static final short OPERATOR_EQUAL = 1;
    private static final short OPERATOR_NOT_EQUAL = 2;
    private static final short OPERATOR_GREATER_THAN = 3;
    private static final short OPERATOR_LESS_THAN = 4;
    private static final short OPERATOR_GREATER_THAN_OR_EQUAL = 5;
    private static final short OPERATOR_LESS_THAN_OR_EQUAL = 6;
    private static final short OPERATOR_INSTANCEOF = 7;

    // if we are doing an instanceof test the class we want to test against
    Class instanceOfClass = null;

    // the rule that "owns" this condition.
    private RuleBase rule;


    /**
     * Will check and see if the condition matches the request.
     *
     * @param hsRequest
     * @return true on match
     * @deprecated use getConditionMatch(HttpServletRequest hsRequest)
     */
    public boolean matches(final HttpServletRequest hsRequest) {
        return getConditionMatch(hsRequest) != null;
    }

    /**
     * Will check and see if the condition matches the request.
     *
     * @param hsRequest
     * @return true on match
     */
    public ConditionMatch getConditionMatch(final HttpServletRequest hsRequest) {
        if (!initialised) {
            log.debug("condition not initialised skipping");
            // error initialising do not process
            return null;
        }
        if (!valid) {
            log.debug("condition not valid skipping");
            return null;
        }

        switch (type) {
            case TYPE_TIME:
                return evaluateNumericCondition(System.currentTimeMillis());
            case TYPE_TIME_YEAR:
                return evaluateCalendarCondition(Calendar.YEAR);
            case TYPE_TIME_MONTH:
                return evaluateCalendarCondition(Calendar.MONTH);
            case TYPE_TIME_DAY_OF_MONTH:
                return evaluateCalendarCondition(Calendar.DAY_OF_MONTH);
            case TYPE_TIME_DAY_OF_WEEK:
                return evaluateCalendarCondition(Calendar.DAY_OF_WEEK);
            case TYPE_TIME_AMPM:
                return evaluateCalendarCondition(Calendar.AM_PM);
            case TYPE_TIME_HOUR_OF_DAY:
                return evaluateCalendarCondition(Calendar.HOUR_OF_DAY);
            case TYPE_TIME_MINUTE:
                return evaluateCalendarCondition(Calendar.MINUTE);
            case TYPE_TIME_SECOND:
                return evaluateCalendarCondition(Calendar.SECOND);
            case TYPE_TIME_MILLISECOND:
                return evaluateCalendarCondition(Calendar.MILLISECOND);

            case TYPE_ATTRIBUTE:
                return evaluateAttributeCondition(name == null ? null : hsRequest.getAttribute(name));
            case TYPE_AUTH_TYPE:
                return evaluateStringCondition(hsRequest.getAuthType());
            case TYPE_CHARACTER_ENCODING:
                return evaluateStringCondition(hsRequest.getCharacterEncoding());
            case TYPE_CONTENT_LENGTH:
                return evaluateNumericCondition(hsRequest.getContentLength());
            case TYPE_CONTENT_TYPE:
                return evaluateStringCondition(hsRequest.getContentType());
            case TYPE_CONTEXT_PATH:
                return evaluateStringCondition(hsRequest.getContextPath());
            case TYPE_COOKIE:
                return evaluateCookieCondition(hsRequest.getCookies(), name);
            case TYPE_LOCAL_PORT:
                return evaluateNumericCondition(hsRequest.getLocalPort());
            case TYPE_METHOD:
                return evaluateStringCondition(hsRequest.getMethod());
            case TYPE_PARAMETER:
                return evaluateStringCondition(name == null ? null : hsRequest.getParameter(name));
            case TYPE_PATH_INFO:
                return evaluateStringCondition(hsRequest.getPathInfo());
            case TYPE_PATH_TRANSLATED:
                return evaluateStringCondition(hsRequest.getPathTranslated());
            case TYPE_PROTOCOL:
                return evaluateStringCondition(hsRequest.getProtocol());
            case TYPE_QUERY_STRING:
                return evaluateStringCondition(hsRequest.getQueryString());
            case TYPE_REMOTE_ADDR:
                return evaluateStringCondition(hsRequest.getRemoteAddr());
            case TYPE_REMOTE_HOST:
                return evaluateStringCondition(hsRequest.getRemoteHost());
            case TYPE_REMOTE_USER:
                return evaluateStringCondition(hsRequest.getRemoteUser());
            case TYPE_REQUESTED_SESSION_ID:
                return evaluateStringCondition(hsRequest.getRequestedSessionId());
            case TYPE_REQUEST_URI:
                return evaluateStringCondition(hsRequest.getRequestURI());
            case TYPE_REQUEST_URL:
                StringBuffer requestUrlBuff = hsRequest.getRequestURL();
                String requestUrlStr = null;
                if (requestUrlBuff != null) {
                    requestUrlStr = requestUrlBuff.toString();
                }
                return evaluateStringCondition(requestUrlStr);
            case TYPE_SESSION_ATTRIBUTE:
                Object sessionAttributeValue = null;
                final HttpSession session = hsRequest.getSession(false);
                if (session != null && name != null) {
                    sessionAttributeValue = session.getAttribute(name);
                }
                return evaluateAttributeCondition(sessionAttributeValue);

            case TYPE_SESSION_IS_NEW:
                boolean sessionNew = false;
                final HttpSession sessionIsNew = hsRequest.getSession(false);
                if (sessionIsNew != null) {
                    sessionNew = sessionIsNew.isNew();
                }
                return evaluateBoolCondition(sessionNew);
            case TYPE_SERVER_PORT:
                return evaluateNumericCondition(hsRequest.getServerPort());
            case TYPE_SERVER_NAME:
                return evaluateStringCondition(hsRequest.getServerName());
            case TYPE_SCHEME:
                return evaluateStringCondition(hsRequest.getScheme());
            case TYPE_USER_IN_ROLE:
                log.debug("is user in role " + name + " op " + operator);
                return evaluateBoolCondition(hsRequest.isUserInRole(name));

            case TYPE_EXCEPTION:
                String eName = null;
                Exception e = (Exception) hsRequest.getAttribute("javax.servlet.error.exception");

                if (OPERATOR_INSTANCEOF == operator) {
                    return evaluateInstanceOfCondition(e);
                } else {
                    if (e != null && e.getClass() != null) eName = e.getClass().getName();
                    return evaluateStringCondition(eName);
                }

            default:
                return evaluateHeaderCondition(hsRequest);
        }
    }

    private ConditionMatch evaluateAttributeCondition(Object attribObject) {
        String attribValue = null;
        if (attribObject == null) {
            if (log.isDebugEnabled()) {
                log.debug(name + " doesn't exist");
            }
        } else {
            attribValue = attribObject.toString();
        }
        if (OPERATOR_INSTANCEOF == operator) {
            return evaluateInstanceOfCondition(attribObject);
        } else {
            return evaluateStringCondition(attribValue);
        }
    }

    private ConditionMatch evaluateInstanceOfCondition(Object obj) {
        // only test for instanceof if object is not null
        if (obj == null) return null;

        if (log.isDebugEnabled()) {
            log.debug("is " + obj.getClass() + " an instanceof " + instanceOfClass);
        }
        if (instanceOfClass == null) {
            log.error("this condition may have failed to initialise correctly, instanceof class is null");
            return null;
        }
        if (instanceOfClass.isInstance(obj)) {
            log.debug("yes");
            return new ConditionMatch();
        }
        log.debug("no");
        return null;
    }


    private ConditionMatch evaluateCookieCondition(Cookie[] cookies, String name) {
        if (cookies == null) {
            // we will have to do an exists check
            return evaluateBoolCondition(false);
        }
        if (name == null) {
            return evaluateBoolCondition(false);
        }
        for (int i = 0; i < cookies.length; i++) {
            Cookie cookie = cookies[i];
            if (cookie == null) {
                continue;
            }
            if (name.equals(cookie.getName())) {
                return evaluateStringCondition(cookie.getValue());
            }
        }
        return evaluateBoolCondition(false);
    }


    private ConditionMatch evaluateStringCondition(String value) {
        if (pattern == null && value == null) {
            log.debug("value is empty and pattern is also, condition false");
            return evaluateBoolCondition(false);
        } else if (pattern == null) {
            log.debug("value isn't empty but pattern is, assuming checking for existence, condition true");
            return evaluateBoolCondition(true);
        }
        if (value == null) {
            // value is null make value ""
            value = "";
        }
        if (log.isDebugEnabled()) {
            log.debug("evaluating \"" + value + "\" against " + strValue);
        }
        StringMatchingMatcher matcher = pattern.matcher(value);
        return evaluateBoolCondition(matcher, matcher.find());
    }

    /**
     * Evaluate taking into account the operator, not only boolean operators considered.
     */
    private ConditionMatch evaluateBoolCondition(boolean outcome) {
        if (log.isTraceEnabled()) {
            log.trace("outcome " + outcome);
        }
        if (operator == OPERATOR_NOT_EQUAL) {
            log.debug("not equal operator in use");
            return !outcome ? new ConditionMatch() : null;
        }
        return outcome ? new ConditionMatch() : null;
    }