Package org.apache.nutch.parse

Source Code of org.apache.nutch.parse.ParseOutputFormat

/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements.  See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License.  You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

package org.apache.nutch.parse;

// Commons Logging imports
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hadoop.conf.*;
import org.apache.hadoop.io.*;
import org.apache.hadoop.io.SequenceFile.CompressionType;
import org.apache.hadoop.fs.*;
import org.apache.hadoop.mapred.*;
import org.apache.hadoop.util.StringUtils;
import org.apache.nutch.crawl.CrawlDatum;
import org.apache.nutch.fetcher.Fetcher;
import org.apache.nutch.scoring.ScoringFilterException;
import org.apache.nutch.scoring.ScoringFilters;
import org.apache.nutch.util.StringUtil;
import org.apache.nutch.util.URLUtil;
import org.apache.nutch.metadata.Nutch;
import org.apache.nutch.net.*;

import java.io.*;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.Map.Entry;

import org.apache.hadoop.util.Progressable;

/* Parse content in a segment. */
public class ParseOutputFormat implements OutputFormat<Text, Parse> {
  private static final Logger LOG = LoggerFactory.getLogger(ParseOutputFormat.class);

  private URLFilters filters;
  private URLNormalizers normalizers;
  private ScoringFilters scfilters;

  private static class SimpleEntry implements Entry<Text, CrawlDatum> {
    private Text key;
    private CrawlDatum value;
   
    public SimpleEntry(Text key, CrawlDatum value) {
      this.key = key;
      this.value = value;
    }
   
    public Text getKey() {
      return key;
    }
   
    public CrawlDatum getValue() {
      return value;
    }

    public CrawlDatum setValue(CrawlDatum value) {
      this.value = value;
      return this.value;
    }
  }

  public void checkOutputSpecs(FileSystem fs, JobConf job) throws IOException {
      Path out = FileOutputFormat.getOutputPath(job);
      if ((out == null) && (job.getNumReduceTasks() != 0)) {
          throw new InvalidJobConfException(
                  "Output directory not set in JobConf.");
      }
      if (fs == null) {
          fs = out.getFileSystem(job);
      }
      if (fs.exists(new Path(out, CrawlDatum.PARSE_DIR_NAME)))
          throw new IOException("Segment already parsed!");
  }

  public RecordWriter<Text, Parse> getRecordWriter(FileSystem fs, JobConf job,
                                      String name, Progressable progress) throws IOException {

    if(job.getBoolean("parse.filter.urls", true)) {
      filters = new URLFilters(job);
    }

    if(job.getBoolean("parse.normalize.urls", true)) {
      normalizers = new URLNormalizers(job, URLNormalizers.SCOPE_OUTLINK);
    }

    this.scfilters = new ScoringFilters(job);
    final int interval = job.getInt("db.fetch.interval.default", 2592000);
    final boolean ignoreExternalLinks = job.getBoolean("db.ignore.external.links", false);
    int maxOutlinksPerPage = job.getInt("db.max.outlinks.per.page", 100);
    final boolean isParsing = job.getBoolean("fetcher.parse", true);
    final int maxOutlinks = (maxOutlinksPerPage < 0) ? Integer.MAX_VALUE
                                                     : maxOutlinksPerPage;
    final CompressionType compType = SequenceFileOutputFormat.getOutputCompressionType(job);
    Path out = FileOutputFormat.getOutputPath(job);
   
    Path text = new Path(new Path(out, ParseText.DIR_NAME), name);
    Path data = new Path(new Path(out, ParseData.DIR_NAME), name);
    Path crawl = new Path(new Path(out, CrawlDatum.PARSE_DIR_NAME), name);
   
    final String[] parseMDtoCrawlDB = job.get("db.parsemeta.to.crawldb","").split(" *, *");
   
    final MapFile.Writer textOut =
      new MapFile.Writer(job, fs, text.toString(), Text.class, ParseText.class,
          CompressionType.RECORD, progress);
   
    final MapFile.Writer dataOut =
      new MapFile.Writer(job, fs, data.toString(), Text.class, ParseData.class,
          compType, progress);
   
    final SequenceFile.Writer crawlOut =
      SequenceFile.createWriter(fs, job, crawl, Text.class, CrawlDatum.class,
          compType, progress);
   
    return new RecordWriter<Text, Parse>() {


        public void write(Text key, Parse parse)
          throws IOException {
         
          String fromUrl = key.toString();
          String fromHost = null;
          textOut.append(key, new ParseText(parse.getText()));
         
          ParseData parseData = parse.getData();
          // recover the signature prepared by Fetcher or ParseSegment
          String sig = parseData.getContentMeta().get(Nutch.SIGNATURE_KEY);
          if (sig != null) {
            byte[] signature = StringUtil.fromHexString(sig);
            if (signature != null) {
              // append a CrawlDatum with a signature
              CrawlDatum d = new CrawlDatum(CrawlDatum.STATUS_SIGNATURE, 0);
              d.setSignature(signature);
              crawlOut.append(key, d);
            }
          }
         
        // see if the parse metadata contain things that we'd like
        // to pass to the metadata of the crawlDB entry
        CrawlDatum parseMDCrawlDatum = null;
        for (String mdname : parseMDtoCrawlDB) {
          String mdvalue = parse.getData().getParseMeta().get(mdname);
          if (mdvalue != null) {
            if (parseMDCrawlDatum == null) parseMDCrawlDatum = new CrawlDatum(
                CrawlDatum.STATUS_PARSE_META, 0);
            parseMDCrawlDatum.getMetaData().put(new Text(mdname),
                new Text(mdvalue));
          }
        }
        if (parseMDCrawlDatum != null) crawlOut.append(key, parseMDCrawlDatum);

        if (ignoreExternalLinks) {
          // need to determine fromHost (once for all outlinks)
          try {
            fromHost = new URL(fromUrl).getHost().toLowerCase();
          } catch (MalformedURLException e) {
            fromHost = null;
          }
        } else {
          fromHost = null;
        }

        ParseStatus pstatus = parseData.getStatus();
        if (pstatus != null && pstatus.isSuccess()
            && pstatus.getMinorCode() == ParseStatus.SUCCESS_REDIRECT) {
          String newUrl = pstatus.getMessage();
          int refreshTime = Integer.valueOf(pstatus.getArgs()[1]);
          newUrl = filterNormalize(fromUrl, newUrl, fromHost,
              ignoreExternalLinks, filters, normalizers,
              URLNormalizers.SCOPE_FETCHER);

          if (newUrl != null) {
            String reprUrl = URLUtil.chooseRepr(fromUrl, newUrl,
                refreshTime < Fetcher.PERM_REFRESH_TIME);
            CrawlDatum newDatum = new CrawlDatum();
            newDatum.setStatus(CrawlDatum.STATUS_LINKED);
            if (reprUrl != null && !reprUrl.equals(newUrl)) {
              newDatum.getMetaData().put(Nutch.WRITABLE_REPR_URL_KEY,
                  new Text(reprUrl));
            }
            crawlOut.append(new Text(newUrl), newDatum);
          }
        }

          // collect outlinks for subsequent db update
          Outlink[] links = parseData.getOutlinks();
          int outlinksToStore = Math.min(maxOutlinks, links.length);

          int validCount = 0;
          CrawlDatum adjust = null;
          List<Entry<Text, CrawlDatum>> targets = new ArrayList<Entry<Text, CrawlDatum>>(outlinksToStore);
          List<Outlink> outlinkList = new ArrayList<Outlink>(outlinksToStore);
          for (int i = 0; i < links.length && validCount < outlinksToStore; i++) {
            String toUrl = links[i].getToUrl();

            // Only normalize and filter if fetcher.parse = false
            if (!isParsing) {
              toUrl = ParseOutputFormat.filterNormalize(fromUrl, toUrl, fromHost, ignoreExternalLinks, filters, normalizers);
              if (toUrl == null) {
                continue;
              }
            }

            CrawlDatum target = new CrawlDatum(CrawlDatum.STATUS_LINKED, interval);
            Text targetUrl = new Text(toUrl);
           
            // see if the outlink has any metadata attached
            // and if so pass that to the crawldatum so that
            // the initial score or distribution can use that
            MapWritable outlinkMD = links[i].getMetadata();
            if (outlinkMD!=null){
              target.getMetaData().putAll(outlinkMD);
            }
           
            try {
              scfilters.initialScore(targetUrl, target);
            } catch (ScoringFilterException e) {
              LOG.warn("Cannot filter init score for url " + key +
                      ", using default: " + e.getMessage());
              target.setScore(0.0f);
            }

            targets.add(new SimpleEntry(targetUrl, target));

            // OVerwrite URL in Outlink object with normalized URL (NUTCH-1174)
            links[i].setUrl(toUrl);
            outlinkList.add(links[i]);
            validCount++;
          }

          try {
            // compute score contributions and adjustment to the original score
            adjust = scfilters.distributeScoreToOutlinks(key, parseData,
                      targets, null, links.length);
          } catch (ScoringFilterException e) {
            LOG.warn("Cannot distribute score from " + key + ": " + e.getMessage());
          }
          for (Entry<Text, CrawlDatum> target : targets) {
            crawlOut.append(target.getKey(), target.getValue());
          }
          if (adjust != null) crawlOut.append(key, adjust);

          Outlink[] filteredLinks = outlinkList.toArray(new Outlink[outlinkList.size()]);
          parseData = new ParseData(parseData.getStatus(), parseData.getTitle(),
                                    filteredLinks, parseData.getContentMeta(),
                                    parseData.getParseMeta());
          dataOut.append(key, parseData);
          if (!parse.isCanonical()) {
            CrawlDatum datum = new CrawlDatum();
            datum.setStatus(CrawlDatum.STATUS_FETCH_SUCCESS);
            String timeString = parse.getData().getContentMeta().get(Nutch.FETCH_TIME_KEY);
            try {
              datum.setFetchTime(Long.parseLong(timeString));
            } catch (Exception e) {
              LOG.warn("Can't read fetch time for: " + key);
              datum.setFetchTime(System.currentTimeMillis());
            }
            crawlOut.append(key, datum);
          }
        }
       
        public void close(Reporter reporter) throws IOException {
          textOut.close();
          dataOut.close();
          crawlOut.close();
        }
       
      };
   
  }

  public static String filterNormalize(String fromUrl, String toUrl,
      String fromHost, boolean ignoreExternalLinks, URLFilters filters,
      URLNormalizers normalizers) {
    return filterNormalize(fromUrl, toUrl, fromHost, ignoreExternalLinks,
        filters, normalizers, URLNormalizers.SCOPE_OUTLINK);
  }

  public static String filterNormalize(String fromUrl, String toUrl,
      String fromHost, boolean ignoreExternalLinks, URLFilters filters,
      URLNormalizers normalizers, String urlNormalizerScope) {
    // ignore links to self (or anchors within the page)
    if (fromUrl.equals(toUrl)) {
      return null;
    }
    if (ignoreExternalLinks) {
      String toHost;
      try {
        toHost = new URL(toUrl).getHost().toLowerCase();
      } catch (MalformedURLException e) {
        toHost = null;
      }
      if (toHost == null || !toHost.equals(fromHost)) { // external links
        return null; // skip it
      }
    }
    try {
      if(normalizers != null) {
        toUrl = normalizers.normalize(toUrl,
                  urlNormalizerScope);   // normalize the url
      }
      if (filters != null) {
        toUrl = filters.filter(toUrl);   // filter the url
      }
      if (toUrl == null) {
        return null;
      }
    } catch (Exception e) {
      return null;
    }

    return toUrl;
  }

}
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