/*
* 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.tika;
import java.io.ByteArrayInputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Map;
import org.apache.hadoop.conf.Configuration;
import org.apache.html.dom.HTMLDocumentImpl;
import org.apache.nutch.metadata.Nutch;
import org.apache.nutch.parse.HTMLMetaTags;
import org.apache.nutch.parse.HtmlParseFilters;
import org.apache.nutch.parse.Outlink;
import org.apache.nutch.parse.OutlinkExtractor;
import org.apache.nutch.parse.Parse;
import org.apache.nutch.parse.ParseData;
import org.apache.nutch.parse.ParseImpl;
import org.apache.nutch.parse.ParseResult;
import org.apache.nutch.parse.ParseStatus;
import org.apache.nutch.protocol.Content;
import org.apache.tika.config.TikaConfig;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.parser.Parser;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.w3c.dom.DocumentFragment;
/**
* Wrapper for Tika parsers. Mimics the HTMLParser but using the XHTML
* representation returned by Tika as SAX events
***/
public class TikaParser implements org.apache.nutch.parse.Parser {
public static final Logger LOG = LoggerFactory.getLogger(TikaParser.class);
private Configuration conf;
private TikaConfig tikaConfig = null;
private DOMContentUtils utils;
private HtmlParseFilters htmlParseFilters;
private String cachingPolicy;
@SuppressWarnings("deprecation")
public ParseResult getParse(Content content) {
String mimeType = content.getContentType();
URL base;
try {
base = new URL(content.getBaseUrl());
} catch (MalformedURLException e) {
return new ParseStatus(e).getEmptyParseResult(content.getUrl(),
getConf());
}
// get the right parser using the mime type as a clue
Parser parser = tikaConfig.getParser(MediaType.parse(mimeType));
byte[] raw = content.getContent();
if (parser == null) {
String message = "Can't retrieve Tika parser for mime-type "
+ mimeType;
LOG.error(message);
return new ParseStatus(ParseStatus.FAILED, message)
.getEmptyParseResult(content.getUrl(), getConf());
}
LOG.debug("Using Tika parser " + parser.getClass().getName()
+ " for mime-type " + mimeType);
Metadata tikamd = new Metadata();
HTMLDocumentImpl doc = new HTMLDocumentImpl();
doc.setErrorChecking(false);
DocumentFragment root = doc.createDocumentFragment();
DOMBuilder domhandler = new DOMBuilder(doc, root);
ParseContext context = new ParseContext();
tikamd.set(Metadata.CONTENT_TYPE, mimeType);
try {
parser.parse(new ByteArrayInputStream(raw), domhandler, tikamd,context);
} catch (Exception e) {
LOG.error("Error parsing "+content.getUrl(),e);
return new ParseStatus(ParseStatus.FAILED, e.getMessage())
.getEmptyParseResult(content.getUrl(), getConf());
}
HTMLMetaTags metaTags = new HTMLMetaTags();
String text = "";
String title = "";
Outlink[] outlinks = new Outlink[0];
org.apache.nutch.metadata.Metadata nutchMetadata = new org.apache.nutch.metadata.Metadata();
// we have converted the sax events generated by Tika into a DOM object
// so we can now use the usual HTML resources from Nutch
// get meta directives
HTMLMetaProcessor.getMetaTags(metaTags, root, base);
if (LOG.isTraceEnabled()) {
LOG.trace("Meta tags for " + base + ": " + metaTags.toString());
}
// check meta directives
if (!metaTags.getNoIndex()) { // okay to index
StringBuffer sb = new StringBuffer();
if (LOG.isTraceEnabled()) {
LOG.trace("Getting text...");
}
utils.getText(sb, root); // extract text
text = sb.toString();
sb.setLength(0);
if (LOG.isTraceEnabled()) {
LOG.trace("Getting title...");
}
utils.getTitle(sb, root); // extract title
title = sb.toString().trim();
}
if (!metaTags.getNoFollow()) { // okay to follow links
ArrayList<Outlink> l = new ArrayList<Outlink>(); // extract outlinks
URL baseTag = utils.getBase(root);
if (LOG.isTraceEnabled()) {
LOG.trace("Getting links...");
}
utils.getOutlinks(baseTag != null ? baseTag : base, l, root);
outlinks = l.toArray(new Outlink[l.size()]);
if (LOG.isTraceEnabled()) {
LOG.trace("found " + outlinks.length + " outlinks in "
+ content.getUrl());
}
}
// populate Nutch metadata with Tika metadata
String[] TikaMDNames = tikamd.names();
for (String tikaMDName : TikaMDNames) {
if (tikaMDName.equalsIgnoreCase(Metadata.TITLE))
continue;
// TODO what if multivalued?
nutchMetadata.add(tikaMDName, tikamd.get(tikaMDName));
}
// no outlinks? try OutlinkExtractor e.g works for mime types where no
// explicit markup for anchors
if (outlinks.length == 0) {
outlinks = OutlinkExtractor.getOutlinks(text, getConf());
}
ParseStatus status = new ParseStatus(ParseStatus.SUCCESS);
if (metaTags.getRefresh()) {
status.setMinorCode(ParseStatus.SUCCESS_REDIRECT);
status.setArgs(new String[] { metaTags.getRefreshHref().toString(),
Integer.toString(metaTags.getRefreshTime()) });
}
ParseData parseData = new ParseData(status, title, outlinks, content
.getMetadata(), nutchMetadata);
ParseResult parseResult = ParseResult.createParseResult(content
.getUrl(), new ParseImpl(text, parseData));
// run filters on parse
ParseResult filteredParse = this.htmlParseFilters.filter(content,
parseResult, metaTags, root);
if (metaTags.getNoCache()) { // not okay to cache
for (Map.Entry<org.apache.hadoop.io.Text, Parse> entry : filteredParse)
entry.getValue().getData().getParseMeta().set(
Nutch.CACHING_FORBIDDEN_KEY, cachingPolicy);
}
return filteredParse;
}
public void setConf(Configuration conf) {
this.conf = conf;
this.tikaConfig = null;
// do we want a custom Tika configuration file
// deprecated since Tika 0.7 which is based on
// a service provider based configuration
String customConfFile = conf.get("tika.config.file");
if (customConfFile != null) {
try {
// see if a Tika config file can be found in the job file
URL customTikaConfig = conf.getResource(customConfFile);
if (customTikaConfig != null)
tikaConfig = new TikaConfig(customTikaConfig);
} catch (Exception e1) {
String message = "Problem loading custom Tika configuration from "
+ customConfFile;
LOG.error(message, e1);
}
} else {
try {
tikaConfig = new TikaConfig(this.getClass().getClassLoader());
} catch (Exception e2) {
String message = "Problem loading default Tika configuration";
LOG.error(message, e2);
}
}
this.htmlParseFilters = new HtmlParseFilters(getConf());
this.utils = new DOMContentUtils(conf);
this.cachingPolicy = getConf().get("parser.caching.forbidden.policy",
Nutch.CACHING_FORBIDDEN_CONTENT);
}
public Configuration getConf() {
return this.conf;
}
}