src/plugin/parsefilter-debug/src/java/org/apache/nutch/parsefilter/debug/DebugParseFilter.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.parsefilter.debug;

import java.io.ByteArrayOutputStream;
import java.io.OutputStreamWriter;
import java.lang.invoke.MethodHandles;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;

import org.apache.hadoop.conf.Configuration;
import org.apache.nutch.metadata.Metadata;
import org.apache.nutch.parse.HTMLMetaTags;
import org.apache.nutch.parse.HtmlParseFilter;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.protocol.Content;
import org.apache.nutch.util.DomUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.DocumentFragment;

/**
 * Adds serialized DOM to parse data, useful for debugging, to understand how
 * the parser implementation interprets a document (not only HTML).
 */
public class DebugParseFilter implements HtmlParseFilter {

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

  private Configuration conf;

  @Override
  public ParseResult filter(Content content, ParseResult parseResult, HTMLMetaTags metaTags, DocumentFragment doc) {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    DomUtil.saveDom(baos, doc);
    Parse parse = parseResult.get(content.getUrl());
    String dom = new String(baos.toByteArray(), StandardCharsets.UTF_8);
    LOG.debug(dom);
    parse.getData().getParseMeta().set("DOM", dom);
    return parseResult;
  }

  @Override
  public void setConf(Configuration conf) {
    this.conf = conf;
  }

  @Override
  public Configuration getConf() {
    return conf;
  }
}