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

// Request.java
// (C) 2007 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany
// first published 14.03.2007 on http://yacy.net
//
// This is a part of YaCy, a peer-to-peer based web search engine
//
// $LastChangedDate$
// $LastChangedRevision$
// $LastChangedBy$
//
// LICENSE
// 
// 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.io.UnsupportedEncodingException;
import java.util.Date;

import net.yacy.kelondro.data.meta.DigestURI;
import net.yacy.kelondro.data.word.Word;
import net.yacy.kelondro.index.Row;
import net.yacy.kelondro.order.Base64Order;
import net.yacy.kelondro.order.Bitfield;
import net.yacy.kelondro.order.NaturalOrder;
import net.yacy.kelondro.workflow.WorkflowJob;

public class Request extends WorkflowJob {
    
    // row definition for balancer-related NURL-entries
    public final static Row rowdef = new Row(
        "String urlhash-" + Word.commonHashLength + ", " +    // the url's hash
        "String initiator-" + Word.commonHashLength + ", " +  // the crawling initiator
        "String urlstring-256, " +                            // the url as string
        "String refhash-" + Word.commonHashLength + ", " +    // the url's referrer hash
        "String urlname-80, " +                               // the name of the url, from anchor tag <a>name</a>
        "Cardinal appdate-8 {b256}, " +                       // the time when the url was first time appeared
        "String profile-" + Word.commonHashLength + ", " +    // the name of the prefetch profile handle
        "Cardinal depth-2 {b256}, " +                         // the prefetch depth so far, starts at 0
        "Cardinal parentbr-3 {b256}, " +                      // number of anchors of the parent
        "Cardinal forkfactor-4 {b256}, " +                    // sum of anchors of all ancestors
        "byte[] flags-4, " +                                  // flags
        "String handle-4, " +                                 // extra handle
        "Cardinal loaddate-8 {b256}," +                       // NOT USED
        "Cardinal lastmodified-8 {b256}," +                   // NOT USED
        "Cardinal modifiedSince-8 {b256}",                    // time that was given to server as ifModifiedSince
        Base64Order.enhancedCoder
    );
    
    private byte[]   initiator;     // the initiator hash, is NULL or "" if it is the own proxy;
                                    // if this is generated by a crawl, the own peer hash in entered
    private byte[]   refhash;       // the url's referrer hash
    private DigestURI url;          // the url as string
    private String   name;          // the name of the url, from anchor tag <a>name</a>     
    private long     appdate;       // the time when the url was first time appeared. may be negative in case that the date is before epoch (1970)!
    private long     imsdate;       // the time of a ifModifiedSince request
    private String   profileHandle; // the name of the fetch profile
    private int      depth;         // the prefetch depth so far, starts at 0
    private int      anchors;       // number of anchors of the parent
    private int      forkfactor;    // sum of anchors of all ancestors
    private Bitfield flags;
    private int      handle;
    private String   statusMessage;
    private int      initialHash;   // to provide a object hash that does not change even if the url changes because of redirection
    
    /**
     * convenience method for 'full' request object
     * @param url
     * @param referrerhash
     */
    public Request(final DigestURI url, final byte[] referrerhash) {
        this(null, url, referrerhash, null, null, null, 0, 0, 0);
    }
    
    /**
     * A Request Entry is a object that is created to provide
     * all information to load a specific resource.
     * 
     * @param initiator the hash of the initiator peer
     * @param url the {@link URL} to crawl
     * @param referrer the hash of the referrer URL
     * @param name the name of the document to crawl
     * @param appdate the time when the url was first time appeared
     * @param profileHandle the name of the prefetch profile. This must not be null!
     * @param depth the crawling depth of the entry 
     * @param anchors number of anchors of the parent
     * @param forkfactor sum of anchors of all ancestors
     */
    public Request(
            final byte[] initiator, 
            final DigestURI url, 
            final byte[] referrerhash, 
            final String name, 
            final Date appdate,
            final String profileHandle,
            final int depth, 
            final int anchors, 
            final int forkfactor
    ) {
        // create new entry and store it into database
        assert url != null;
        assert profileHandle == null || profileHandle.length() == Word.commonHashLength : profileHandle + " != " + Word.commonHashLength;
        url.removeRef(); // remove anchor reference
        this.initiator     = (initiator == null) ? null : ((initiator.length == 0) ? null : initiator);
        this.url           = url;
        this.refhash       = referrerhash;
        this.name          = (name == null) ? "" : name;
        this.appdate       = (appdate == null) ? 0 : appdate.getTime();
        this.profileHandle = profileHandle; // must not be null
        this.depth         = depth;
        this.anchors       = anchors;
        this.forkfactor    = forkfactor;
        this.flags         = new Bitfield(rowdef.width(10));
        this.handle        = 0;
        this.imsdate       = 0;
        this.statusMessage = "loaded(args)";
        this.initialHash   = url.hashCode();
        this.status        = WorkflowJob.STATUS_INITIATED;
    }
    
    public Request(final Row.Entry entry) throws IOException {
        assert (entry != null);
        insertEntry(entry);
    }

    private void insertEntry(final Row.Entry entry) throws IOException {
        final String urlstring = entry.getColString(2, null);
        if (urlstring == null) throw new IOException ("url string is null");
        this.initiator = entry.getColBytes(1, true);
        this.initiator = (initiator == null) ? null : ((initiator.length == 0) ? null : initiator);
        this.url = new DigestURI(urlstring, entry.getColBytes(0, true));
        this.refhash = (entry.empty(3)) ? null : entry.getColBytes(3, true);
        this.name = (entry.empty(4)) ? "" : entry.getColString(4, "UTF-8").trim();
        this.appdate = entry.getColLong(5);
        this.profileHandle = (entry.empty(6)) ? null : entry.getColString(6, null).trim();
        this.depth = (int) entry.getColLong(7);
        this.anchors = (int) entry.getColLong(8);
        this.forkfactor = (int) entry.getColLong(9);
        this.flags = new Bitfield(entry.getColBytes(10, true));
        this.handle = Integer.parseInt(entry.getColString(11, null), 16);
        //this.loaddate = entry.getColLong(12);
        //this.lastmodified = entry.getColLong(13);
        this.imsdate = entry.getColLong(14);
        this.statusMessage        = "loaded(kelondroRow.Entry)";
        this.initialHash   = url.hashCode();
        return;
    }
    
    public int hashCode() {
        // overloads Object.hashCode()
        return this.initialHash;
    }
    
    public void setStatus(final String s, int code) {
        //System.out.println("***DEBUG*** crawler status " + s + ", " + code + " for " + this.url.toNormalform(true, false));
        this.statusMessage = s;
        this.status = code;
    }
    
    public String getStatus() {
        return this.statusMessage;
    }
    
    private static String normalizeHandle(final int h) {
        String d = Integer.toHexString(h);
        while (d.length() < rowdef.width(11)) d = "0" + d;
        return d;
    }
    
    public Row.Entry toRow() {
        final byte[] appdatestr = NaturalOrder.encodeLong(appdate, rowdef.width(5));
        final byte[] loaddatestr = NaturalOrder.encodeLong(0 /*loaddate*/, rowdef.width(12));
        final byte[] serverdatestr = NaturalOrder.encodeLong(0 /*lastmodified*/, rowdef.width(13));
        final byte[] imsdatestr = NaturalOrder.encodeLong(imsdate, rowdef.width(14));
        // store the hash in the hash cache
        byte[] namebytes;
        try {
            namebytes = this.name.getBytes("UTF-8");
        } catch (final UnsupportedEncodingException e) {
            namebytes = this.name.getBytes();
        }
        final byte[][] entry = new byte[][] {
                this.url.hash(),
                initiator,
                this.url.toString().getBytes(),
                this.refhash,
                namebytes,
                appdatestr,
                (this.profileHandle == null) ? null : this.profileHandle.getBytes(),
                NaturalOrder.encodeLong(this.depth, rowdef.width(7)),
                NaturalOrder.encodeLong(this.anchors, rowdef.width(8)),
                NaturalOrder.encodeLong(this.forkfactor, rowdef.width(9)),
                this.flags.bytes(),
                normalizeHandle(this.handle).getBytes(),
                loaddatestr,
                serverdatestr,
                imsdatestr};
        return rowdef.newEntry(entry);
    }
    
    public DigestURI url() {
        // the url
        return url;
    }
    
    public void redirectURL(final DigestURI redirectedURL) {
        // replace old URL by new one. This should only be used in case of url redirection
        this.url = redirectedURL;
    }

    public byte[] referrerhash() {
        // the urlhash of a referer url
        return this.refhash;
    }

    public byte[] initiator() {
        // returns the hash of the initiating peer
        return initiator;
    }

    public boolean proxy() {
        // true when the url was retrieved using the proxy
        return (initiator() == null || initiator().length == 0);
    }

    public Date appdate() {
        // the date when the url appeared first
        return new Date(this.appdate);
    }
    /*
    public Date loaddate() {
        // the date when the url was loaded
        return new Date(this.loaddate);
    }
    
    public Date lastmodified() {
        // the date that the server returned as document date
        return new Date(this.lastmodified);
    }
    */
    public Date imsdate() {
        // the date that the client (browser) send as ifModifiedSince in proxy mode
        return new Date(this.imsdate);
    }

    public String name() {
        // return the anchor name (text inside <a> tag)
        return this.name;
    }

    public int depth() {
        // crawl depth where the url appeared
        return this.depth;
    }

    public String profileHandle() {
        // the handle of the crawl profile
        assert profileHandle.length() == Word.commonHashLength : profileHandle + " != " + Word.commonHashLength;
        return this.profileHandle;
    }
    
}