lucene/sandbox/contributions/webcrawler-LARM/libs/HTTPClient-patch/HTTPClient/ContentEncodingModule.java

/*
 *  @(#)ContentEncodingModule.java			0.3-3 06/05/2001
 *
 *  This file is part of the HTTPClient package
 *  Copyright (C) 1996-2001 Ronald Tschalär
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free
 *  Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 *  MA 02111-1307, USA
 *
 *  For questions, suggestions, bug-reports, enhancement-requests etc.
 *  I may be contacted at:
 *
 *  ronald@innovation.ch
 *
 *  The HTTPClient's home page is located at:
 *
 *  http://www.innovation.ch/java/HTTPClient/
 *
 */
package HTTPClient;

import java.io.IOException;
import java.util.Vector;
import java.util.zip.InflaterInputStream;
import java.util.zip.GZIPInputStream;

/**
 * This module handles the Content-Encoding response header. It currently
 * handles the "gzip", "deflate", "compress" and "identity" tokens.
 *
 * @author    Ronald Tschalär
 * @created   29. Dezember 2001
 * @version   0.3-3 06/05/2001
 */
public class ContentEncodingModule implements HTTPClientModule
{
    // Methods

    /**
     * Invoked by the HTTPClient.
     *
     * @param req                  Description of the Parameter
     * @param resp                 Description of the Parameter
     * @return                     Description of the Return Value
     * @exception ModuleException  Description of the Exception
     */
    public int requestHandler(Request req, Response[] resp)
        throws ModuleException
    {
        // parse Accept-Encoding header

        int idx;
        NVPair[] hdrs = req.getHeaders();
        for (idx = 0; idx < hdrs.length; idx++)
        {
            if (hdrs[idx].getName().equalsIgnoreCase("Accept-Encoding"))
            {
                break;
            }
        }

        Vector pae;
        if (idx == hdrs.length)
        {
            hdrs = Util.resizeArray(hdrs, idx + 1);
            req.setHeaders(hdrs);
            pae = new Vector();
        }
        else
        {
            try
            {
                pae = Util.parseHeader(hdrs[idx].getValue());
            }
            catch (ParseException pe)
            {
                throw new ModuleException(pe.toString());
            }
        }

        // done if "*;q=1.0" present

        HttpHeaderElement all = Util.getElement(pae, "*");
        if (all != null)
        {
            NVPair[] params = all.getParams();
            for (idx = 0; idx < params.length; idx++)
            {
                if (params[idx].getName().equalsIgnoreCase("q"))
                {
                    break;
                }
            }

            if (idx == params.length)
            {
                // no qvalue, i.e. q=1.0
                return REQ_CONTINUE;
            }

            if (params[idx].getValue() == null ||
                    params[idx].getValue().length() == 0)
            {
                throw new ModuleException("Invalid q value for \"*\" in " +
                        "Accept-Encoding header: ");
            }

            try
            {
                if (Float.valueOf(params[idx].getValue()).floatValue() > 0.)
                {
                    return REQ_CONTINUE;
                }
            }
            catch (NumberFormatException nfe)
            {
                throw new ModuleException("Invalid q value for \"*\" in " +
                        "Accept-Encoding header: " + nfe.getMessage());
            }
        }

        // Add gzip, deflate and compress tokens to the Accept-Encoding header

        if (!pae.contains(new HttpHeaderElement("deflate")))
        {
            pae.addElement(new HttpHeaderElement("deflate"));
        }
        if (!pae.contains(new HttpHeaderElement("gzip")))
        {
            pae.addElement(new HttpHeaderElement("gzip"));
        }
        if (!pae.contains(new HttpHeaderElement("x-gzip")))
        {
            pae.addElement(new HttpHeaderElement("x-gzip"));
        }
        if (!pae.contains(new HttpHeaderElement("compress")))
        {
            pae.addElement(new HttpHeaderElement("compress"));
        }
        if (!pae.contains(new HttpHeaderElement("x-compress")))
        {
            pae.addElement(new HttpHeaderElement("x-compress"));
        }

        hdrs[idx] = new NVPair("Accept-Encoding", Util.assembleHeader(pae));

        return REQ_CONTINUE;
    }


    /**
     * Invoked by the HTTPClient.
     *
     * @param resp  Description of the Parameter
     * @param req   Description of the Parameter
     */
    public void responsePhase1Handler(Response resp, RoRequest req)
    {
    }


    /**
     * Invoked by the HTTPClient.
     *
     * @param resp  Description of the Parameter
     * @param req   Description of the Parameter
     * @return      Description of the Return Value
     */
    public int responsePhase2Handler(Response resp, Request req)
    {
        return RSP_CONTINUE;
    }


    /**
     * Invoked by the HTTPClient.
     *
     * @param resp                 Description of the Parameter
     * @param req                  Description of the Parameter
     * @exception IOException      Description of the Exception
     * @exception ModuleException  Description of the Exception
     */
    public void responsePhase3Handler(Response resp, RoRequest req)
        throws IOException, ModuleException
    {
        String ce = resp.getHeader("Content-Encoding");
        if (ce == null || req.getMethod().equals("HEAD") ||
                resp.getStatusCode() == 206)
        {
            return;
        }

        Vector pce;
        try
        {
            pce = Util.parseHeader(ce);
        }
        catch (ParseException pe)
        {
            throw new ModuleException(pe.toString());
        }

        if (pce.size() == 0)
        {
            return;
        }

        String encoding = ((HttpHeaderElement) pce.firstElement()).getName();
        if (encoding.equalsIgnoreCase("gzip") ||
                encoding.equalsIgnoreCase("x-gzip"))
        {
            Log.write(Log.MODS, "CEM:   pushing gzip-input-stream");

            resp.inp_stream = new GZIPInputStream(resp.inp_stream);
            pce.removeElementAt(pce.size() - 1);
            resp.deleteHeader("Content-length");
        }
        else if (encoding.equalsIgnoreCase("deflate"))
        {
            Log.write(Log.MODS, "CEM:   pushing inflater-input-stream");

            resp.inp_stream = new InflaterInputStream(resp.inp_stream);
            pce.removeElementAt(pce.size() - 1);
            resp.deleteHeader("Content-length");
        }
        else if (encoding.equalsIgnoreCase("compress") ||
                encoding.equalsIgnoreCase("x-compress"))
        {
            Log.write(Log.MODS, "CEM:   pushing uncompress-input-stream");

            resp.inp_stream = new UncompressInputStream(resp.inp_stream);
            pce.removeElementAt(pce.size() - 1);
            resp.deleteHeader("Content-length");
        }
        else if (encoding.equalsIgnoreCase("identity"))
        {
            Log.write(Log.MODS, "CEM:   ignoring 'identity' token");
            pce.removeElementAt(pce.size() - 1);
        }
        else
        {
            Log.write(Log.MODS, "CEM:   Unknown content encoding '" +
                    encoding + "'");
        }

        if (pce.size() > 0)
        {
            resp.setHeader("Content-Encoding", Util.assembleHeader(pce));
        }
        else
        {
            resp.deleteHeader("Content-Encoding");
        }
    }


    /**
     * Invoked by the HTTPClient.
     *
     * @param resp  Description of the Parameter
     * @param req   Description of the Parameter
     */
    public void trailerHandler(Response resp, RoRequest req)
    {
    }
}