yacy_search_server/source/de/anomic/crawler/retrieval/HTTPLoader.java

// HTTPLoader.java 
// ---------------
// (C) by Michael Peter Christen; mc@yacy.net
// first published on http://yacy.net
// Frankfurt, Germany, 2006
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program 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 General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

package de.anomic.crawler.retrieval;

import java.io.IOException;
import java.util.Date;

import net.yacy.cora.document.MultiProtocolURI;
import net.yacy.kelondro.data.meta.DigestURI;
import net.yacy.kelondro.logging.Log;
import net.yacy.repository.Blacklist;

import de.anomic.crawler.Latency;
import de.anomic.http.client.Client;
import de.anomic.http.server.HeaderFramework;
import de.anomic.http.server.RequestHeader;
import de.anomic.http.server.ResponseContainer;
import de.anomic.search.Segments;
import de.anomic.search.Switchboard;

public final class HTTPLoader {

    private static final String DEFAULT_ENCODING = "gzip,deflate";
    private static final String DEFAULT_LANGUAGE = "en-us,en;q=0.5";
    private static final String DEFAULT_CHARSET = "ISO-8859-1,utf-8;q=0.7,*;q=0.7";
    public  static final long   DEFAULT_MAXFILESIZE = 1024 * 1024 * 10;
    public  static final int    DEFAULT_CRAWLING_RETRY_COUNT = 5;
    public  static final String crawlerUserAgent = "yacybot (" + Client.getSystemOST() +") http://yacy.net/bot.html";
    public  static final String yacyUserAgent = "yacy (" + Client.getSystemOST() +") yacy.net";
    
    /**
     * The socket timeout that should be used
     */
    private final int socketTimeout;
    
    /**
     * The maximum allowed file size
     */
    //private long maxFileSize = -1;
    
    //private String acceptEncoding;
    //private String acceptLanguage;
    //private String acceptCharset;
    private final Switchboard sb;
    private final Log log;
    
    public HTTPLoader(final Switchboard sb, final Log theLog) {
        this.sb = sb;
        this.log = theLog;
        
        // refreshing timeout value
        this.socketTimeout = (int) sb.getConfigLong("crawler.clientTimeout", 10000);
    }  
   
    public Response load(final Request entry, long maxFileSize) throws IOException {
        long start = System.currentTimeMillis();
        Response doc = load(entry, DEFAULT_CRAWLING_RETRY_COUNT, maxFileSize);
        Latency.update(entry.url(), System.currentTimeMillis() - start);
        return doc;
    }
    
    private Response load(final Request request, final int retryCount, final long maxFileSize) throws IOException {

        if (retryCount < 0) {
            sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "redirection counter exceeded");
            throw new IOException("Redirection counter exceeded for URL " + request.url().toString() + ". Processing aborted.");
        }
        
        final String host = request.url().getHost();
        if (host == null || host.length() < 2) throw new IOException("host is not well-formed: '" + host + "'");
        final String path = request.url().getFile();
        int port = request.url().getPort();
        final boolean ssl = request.url().getProtocol().equals("https");
        if (port < 0) port = (ssl) ? 443 : 80;
        
        // check if url is in blacklist
        final String hostlow = host.toLowerCase();
        if (Switchboard.urlBlacklist.isListed(Blacklist.BLACKLIST_CRAWLER, hostlow, path)) {
            sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "url in blacklist");
            throw new IOException("CRAWLER Rejecting URL '" + request.url().toString() + "'. URL is in blacklist.");
        }
        
        // take a file from the net
        Response response = null;
        
        // create a request header
        final RequestHeader requestHeader = new RequestHeader();
        requestHeader.put(HeaderFramework.USER_AGENT, crawlerUserAgent);
        DigestURI refererURL = null;
        if (request.referrerhash() != null) refererURL = sb.getURL(Segments.Process.LOCALCRAWLING, request.referrerhash());
        if (refererURL != null) requestHeader.put(RequestHeader.REFERER, refererURL.toNormalform(true, true));
        requestHeader.put(HeaderFramework.ACCEPT_LANGUAGE, sb.getConfig("crawler.http.acceptLanguage", DEFAULT_LANGUAGE));
        requestHeader.put(HeaderFramework.ACCEPT_CHARSET, sb.getConfig("crawler.http.acceptCharset", DEFAULT_CHARSET));
        requestHeader.put(HeaderFramework.ACCEPT_ENCODING, sb.getConfig("crawler.http.acceptEncoding", DEFAULT_ENCODING));

        // HTTP-Client
        final Client client = new Client(socketTimeout, requestHeader);
        
        ResponseContainer res = null;
        try {
            // send request
            res = client.GET(request.url().toString(), maxFileSize);
            // FIXME: 30*-handling (bottom) is never reached
            // we always get the final content because httpClient.followRedirects = true

            if (res.getStatusCode() == 200 || res.getStatusCode() == 203) {
                // the transfer is ok
                
                // we write the new cache entry to file system directly
                res.setAccountingName("CRAWLER");
                final byte[] responseBody = res.getData();
                long contentLength = responseBody.length;

                // check length again in case it was not possible to get the length before loading
                if (maxFileSize > 0 && contentLength > maxFileSize) {
                	sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "file size limit exceeded");                    
                	throw new IOException("REJECTED URL " + request.url() + " because file size '" + contentLength + "' exceeds max filesize limit of " + maxFileSize + " bytes. (GET)");
                }

                // create a new cache entry
                response = new Response(
                        request,
                        requestHeader,
                        res.getResponseHeader(), 
                        res.getStatusLine(),
                        sb.crawler.profilesActiveCrawls.getEntry(request.profileHandle()),
                        responseBody
                );

                return response;
            } else if (res.getStatusLine().startsWith("30")) {
                if (res.getResponseHeader().containsKey(HeaderFramework.LOCATION)) {
                    // getting redirection URL
                    String redirectionUrlString = res.getResponseHeader().get(HeaderFramework.LOCATION);
                    redirectionUrlString = redirectionUrlString.trim();

                    if (redirectionUrlString.length() == 0) {
                        sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "redirection header empy");
                        throw new IOException("CRAWLER Redirection of URL=" + request.url().toString() + " aborted. Location header is empty.");
                    }
                    
                    // normalizing URL
                    final DigestURI redirectionUrl = new DigestURI(MultiProtocolURI.newURL(request.url(), redirectionUrlString));

                    // restart crawling with new url
                    this.log.logInfo("CRAWLER Redirection detected ('" + res.getStatusLine() + "') for URL " + request.url().toString());
                    this.log.logInfo("CRAWLER ..Redirecting request to: " + redirectionUrl);

                    // if we are already doing a shutdown we don't need to retry crawling
                    if (Thread.currentThread().isInterrupted()) {
                        sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "server shutdown");
                        throw new IOException("CRAWLER Retry of URL=" + request.url().toString() + " aborted because of server shutdown.");
                    }
                    
                    // check if the url was already indexed
                    final String dbname = sb.urlExists(Segments.Process.LOCALCRAWLING, redirectionUrl.hash());
                    if (dbname != null) {
                        sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "redirection to double content");
                        throw new IOException("CRAWLER Redirection of URL=" + request.url().toString() + " ignored. The url appears already in db " + dbname);
                    }
                    
                    // retry crawling with new url
                    request.redirectURL(redirectionUrl);
                    return load(request, retryCount - 1, maxFileSize);
                }
            } else {
                // if the response has not the right response type then reject file
                sb.crawlQueues.errorURL.push(request, sb.peers.mySeed().hash.getBytes(), new Date(), 1, "wrong http status code " + res.getStatusCode() +  ")");
                throw new IOException("REJECTED WRONG STATUS TYPE '" + res.getStatusLine() + "' for URL " + request.url().toString());
            }
        } finally {
            if(res != null) {
                // release connection
                res.closeStream();
            }
        }
        return response;
    }
    
    public static Response load(final Request request) throws IOException {
        return load(request, 3);
    }
    
    private static Response load(final Request request, int retryCount) throws IOException {

        if (retryCount < 0) {
            throw new IOException("Redirection counter exceeded for URL " + request.url().toString() + ". Processing aborted.");
        }
        
        final String host = request.url().getHost();
        if (host == null || host.length() < 2) throw new IOException("host is not well-formed: '" + host + "'");
        final String path = request.url().getFile();
        int port = request.url().getPort();
        final boolean ssl = request.url().getProtocol().equals("https");
        if (port < 0) port = (ssl) ? 443 : 80;
        
        // check if url is in blacklist
        final String hostlow = host.toLowerCase();
        if (Switchboard.urlBlacklist != null && Switchboard.urlBlacklist.isListed(Blacklist.BLACKLIST_CRAWLER, hostlow, path)) {
            throw new IOException("CRAWLER Rejecting URL '" + request.url().toString() + "'. URL is in blacklist.");
        }
        
        // take a file from the net
        Response response = null;
        
        // create a request header
        final RequestHeader requestHeader = new RequestHeader();
        requestHeader.put(HeaderFramework.USER_AGENT, crawlerUserAgent);
        requestHeader.put(HeaderFramework.ACCEPT_LANGUAGE, DEFAULT_LANGUAGE);
        requestHeader.put(HeaderFramework.ACCEPT_CHARSET, DEFAULT_CHARSET);
        requestHeader.put(HeaderFramework.ACCEPT_ENCODING, DEFAULT_ENCODING);

        // HTTP-Client
        final Client client = new Client(20000, requestHeader);
        
        ResponseContainer res = null;
        try {
            // send request
            res = client.GET(request.url().toString(), Long.MAX_VALUE);
            // FIXME: 30*-handling (bottom) is never reached
            // we always get the final content because httpClient.followRedirects = true

            if (res.getStatusCode() == 200 || res.getStatusCode() == 203) {
                // the transfer is ok
                
                // we write the new cache entry to file system directly
                res.setAccountingName("CRAWLER");
                final byte[] responseBody = res.getData();

                // create a new cache entry
                response = new Response(
                        request,
                        requestHeader,
                        res.getResponseHeader(), 
                        res.getStatusLine(),
                        null,
                        responseBody
                );

                return response;
            } else if (res.getStatusLine().startsWith("30")) {
                if (res.getResponseHeader().containsKey(HeaderFramework.LOCATION)) {
                    // getting redirection URL
                    String redirectionUrlString = res.getResponseHeader().get(HeaderFramework.LOCATION);
                    redirectionUrlString = redirectionUrlString.trim();

                    if (redirectionUrlString.length() == 0) {
                        throw new IOException("CRAWLER Redirection of URL=" + request.url().toString() + " aborted. Location header is empty.");
                    }
                    
                    // normalizing URL
                    final DigestURI redirectionUrl = new DigestURI(MultiProtocolURI.newURL(request.url(), redirectionUrlString));

                    
                    // if we are already doing a shutdown we don't need to retry crawling
                    if (Thread.currentThread().isInterrupted()) {
                        throw new IOException("CRAWLER Retry of URL=" + request.url().toString() + " aborted because of server shutdown.");
                    }
                    
                    // retry crawling with new url
                    request.redirectURL(redirectionUrl);
                    return load(request, retryCount - 1);
                }
            } else {
                // if the response has not the right response type then reject file
                throw new IOException("REJECTED WRONG STATUS TYPE '" + res.getStatusLine() + "' for URL " + request.url().toString());
            }
        } finally {
            if(res != null) {
                // release connection
                res.closeStream();
            }
        }
        return response;
    }
    
}