/* ======================================================================
The Bodington System Software License, Version 1.0
 
Copyright (c) 2001 The University of Leeds.  All rights reserved.
 
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
met:
 
1.  Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
 
2.  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.
 
3.  The end-user documentation included with the redistribution, if any,
must include the following acknowledgement:  "This product includes
software developed by the University of Leeds
(http://www.bodington.org/)."  Alternately, this acknowledgement may
appear in the software itself, if and wherever such third-party
acknowledgements normally appear.
 
4.  The names "Bodington", "Nathan Bodington", "Bodington System",
"Bodington Open Source Project", and "The University of Leeds" must not be
used to endorse or promote products derived from this software without
prior written permission. For written permission, please contact
d.gardner@leeds.ac.uk.
 
5.  The name "Bodington" may not appear in the name of products derived
from this software without prior written permission of the University of
Leeds.
 
THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO,  TITLE,  THE IMPLIED WARRANTIES
OF QUALITY  AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
EVENT SHALL THE UNIVERSITY OF LEEDS OR ITS CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.
=========================================================
 
This software was originally created by the University of Leeds and may contain voluntary
contributions from others.  For more information on the Bodington Open Source Project, please
see http://bodington.org/
 
====================================================================== */

package org.bodington.servlet;

import java.io.File;
import java.util.Properties;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * Utility methods for working in a Servlet enviroment.
 * @author buckett
 */
public class ServletUtils
{
    private static Logger log = Logger.getLogger(ServletUtils.class);
    
    private ServletUtils(){}
    
    /**
     * This method checks to see if we should be returning a not modified response.
     * It looks for a If-Modified-Since header in the HTTP request and uses that to determine
     * if new response is needed. If the header is badly formatted we generate a new response
     * and log the error at WARN level.
     * @param request The HttpServletRequest.
     * @param response The HttpServletResponse.
     * @param last The last time this page was modified.
     * @param expire How many seconds until the response should expire.
     * @return True if we should return a not modified response.
     */
    public static boolean isModified(HttpServletRequest request,
        HttpServletResponse response, long last, int expire)
    {

        long ifModifiedSince = 0;
        
        // HTTP header doesn't allow milliseconds so we should do
        // timestamp comparisons on rounded figures
        last = (last/1000)*1000;
        
        try
        {
            ifModifiedSince = request.getDateHeader( "If-Modified-Since" );
        }
        catch (IllegalArgumentException iae)
        {
            if (log.isEnabledFor(Level.WARN))
            {
                log.warn("Corrupt header (If-Modified-Since: "
                    + request.getHeader("If-Modified-Since") + ") from "
                    + request.getRemoteHost());
            }
        }
        response.setDateHeader( "Last-Modified", last );
        if (expire > 0)
        {
            response.setDateHeader( "Expires", System.currentTimeMillis() + (expire * 1000));
        }
        
        return last <= ifModifiedSince; 
    }

    /**
     * This fixes up some properties. Currently it looks for properties that
     * should have the servlet context prefixed to them, and for directories
     * that should be prefixed with the location of the installation.
     * @param props The properties that will be used to start Bodington.
     * @param context The ServletContext that Bodington is running in.
     */
    public static void adaptConfiguration(Properties props, ServletContext context)
    {
        final int PROP = 0, DEFAULT = 1;
        final String[][] fileProperties = {
            {"buildingservlet.templatedirectory", "templates"},
            {"buildingservlet.templates.classes", "WEB-INF/template_classes"},
            {"webpublish.filestore", "files"},
            {"filegeneration.filestore", "generated"},
            {"buildingservlet.context.root", ""}
        };
    
        for (int count = 0; count < fileProperties.length; count++)
        {
            String value = props.getProperty(fileProperties[count][PROP], fileProperties[count][DEFAULT]);
            File file = new File(value);
            if (!file.isAbsolute())
            {
                value = context.getRealPath(file.getPath());
                props.setProperty(fileProperties[count][PROP], value);
            }
        }
        
    }

}