src/plugin/parse-zip/src/java/org/apache/nutch/parse/zip/ZipTextExtractor.java

/**
 * 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.zip;

import java.lang.invoke.MethodHandles;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;
import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hadoop.conf.Configuration;

import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.net.protocols.Response;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseData;
import org.apache.nutch.parse.ParseUtil;
import org.apache.nutch.parse.ParseException;
import org.apache.nutch.parse.Outlink;
import org.apache.nutch.protocol.Content;
import org.apache.tika.Tika;

/**
 * 
 * @author Rohit Kulkarni and Ashish Vaidya
 */
public class ZipTextExtractor {

  private static final Logger LOG = LoggerFactory
      .getLogger(MethodHandles.lookup().lookupClass());

  private Configuration conf;

  /** Creates a new instance of ZipTextExtractor */
  public ZipTextExtractor(Configuration conf) {
    this.conf = conf;
  }

  public String extractText(InputStream input, String url,
      List<Outlink> outLinksList) throws IOException {
    String resultText = "";
    ZipInputStream zin = new ZipInputStream(input);
    ZipEntry entry;

    while ((entry = zin.getNextEntry()) != null) {

      if (!entry.isDirectory()) {
        int size = (int) entry.getSize();
        byte[] b = new byte[size];
        for (int x = 0; x < size; x++) {
          int err = zin.read();
          if (err != -1) {
            b[x] = (byte) err;
          }
        }
        String newurl = url + "/";
        String fname = entry.getName();
        newurl += fname;
        URL aURL = new URL(newurl);
        String base = aURL.toString();
        int i = fname.lastIndexOf('.');
        if (i != -1) {
          // Trying to resolve the Mime-Type
          Tika tika = new Tika();
          String contentType = tika.detect(fname);
          try {
            Metadata metadata = new Metadata();
            metadata.set(Response.CONTENT_LENGTH,
                Long.toString(entry.getSize()));
            metadata.set(Response.CONTENT_TYPE, contentType);
            Content content = new Content(newurl, base, b, contentType,
                metadata, this.conf);
            Parse parse = new ParseUtil(this.conf).parse(content).get(
                content.getUrl());
            ParseData theParseData = parse.getData();
            Outlink[] theOutlinks = theParseData.getOutlinks();

            for (int count = 0; count < theOutlinks.length; count++) {
              outLinksList.add(new Outlink(theOutlinks[count].getToUrl(),
                  theOutlinks[count].getAnchor()));
            }

            resultText += entry.getName() + " " + parse.getText() + " ";
          } catch (ParseException e) {
            if (LOG.isInfoEnabled()) {
              LOG.info("fetch okay, but can't parse " + fname + ", reason: "
                  + e.getMessage());
            }
          }
        }
      }
    }

    return resultText;
  }

}