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https://issues.apache.org/jira/browse/NUTCH-1465?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15986616#comment-15986616
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ASF GitHub Bot commented on NUTCH-1465:
---------------------------------------
sebastian-nagel commented on a change in pull request #189: NUTCH-1465 Support
sitemaps in Nutch
URL: https://github.com/apache/nutch/pull/189#discussion_r113693977
##########
File path: src/java/org/apache/nutch/util/SitemapProcessor.java
##########
@@ -0,0 +1,436 @@
+/**
+ * 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.util;
+
+import java.io.IOException;
+import java.net.URL;
+import java.text.SimpleDateFormat;
+import java.util.Collection;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Random;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.conf.Configured;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.io.Text;
+import org.apache.hadoop.io.Writable;
+import org.apache.hadoop.mapreduce.Job;
+import org.apache.hadoop.mapreduce.Mapper;
+import org.apache.hadoop.mapreduce.Reducer;
+import org.apache.hadoop.mapreduce.lib.input.KeyValueTextInputFormat;
+import org.apache.hadoop.mapreduce.lib.input.MultipleInputs;
+import org.apache.hadoop.mapreduce.lib.input.SequenceFileInputFormat;
+import org.apache.hadoop.mapreduce.lib.map.MultithreadedMapper;
+import org.apache.hadoop.mapreduce.lib.output.FileOutputFormat;
+import org.apache.hadoop.mapreduce.lib.output.SequenceFileOutputFormat;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.util.Tool;
+import org.apache.hadoop.util.ToolRunner;
+
+import org.apache.nutch.crawl.CrawlDatum;
+import org.apache.nutch.hostdb.HostDatum;
+import org.apache.nutch.net.URLFilters;
+import org.apache.nutch.net.URLNormalizers;
+import org.apache.nutch.protocol.Content;
+import org.apache.nutch.protocol.Protocol;
+import org.apache.nutch.protocol.ProtocolFactory;
+import org.apache.nutch.protocol.ProtocolOutput;
+import org.apache.nutch.protocol.ProtocolStatus;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import crawlercommons.robots.BaseRobotRules;
+import crawlercommons.sitemaps.AbstractSiteMap;
+import crawlercommons.sitemaps.SiteMap;
+import crawlercommons.sitemaps.SiteMapIndex;
+import crawlercommons.sitemaps.SiteMapParser;
+import crawlercommons.sitemaps.SiteMapURL;
+
+/**
+ * <p>Performs Sitemap processing by fetching sitemap links, parsing the
content and merging
+ * the urls from Sitemap (with the metadata) with the existing crawldb.</p>
+ *
+ * <p>There are two use cases supported in Nutch's Sitemap processing:</p>
+ * <ol>
+ * <li>Sitemaps are considered as "remote seed lists". Crawl administrators
can prepare a
+ * list of sitemap links and get only those sitemap pages. This suits well
for targeted
+ * crawl of specific hosts.</li>
+ * <li>For open web crawl, it is not possible to track each host and get the
sitemap links
+ * manually. Nutch would automatically get the sitemaps for all the hosts
seen in the
+ * crawls and inject the urls from sitemap to the crawldb.</li>
+ * </ol>
+ *
+ * <p>For more details see:
+ * https://wiki.apache.org/nutch/SitemapFeature </p>
+ */
+public class SitemapProcessor extends Configured implements Tool {
+ public static final Logger LOG =
LoggerFactory.getLogger(SitemapProcessor.class);
+ public static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd
HH:mm:ss");
+
+ public static final String CURRENT_NAME = "current";
+ public static final String LOCK_NAME = ".locked";
+ public static final String SITEMAP_STRICT_PARSING = "sitemap.strict.parsing";
+ public static final String SITEMAP_URL_FILTERING = "sitemap.url.filter";
+ public static final String SITEMAP_URL_NORMALIZING = "sitemap.url.normalize";
+
+ private static class SitemapMapper extends Mapper<Text, Writable, Text,
CrawlDatum> {
+ private ProtocolFactory protocolFactory = null;
+ private boolean strict = true;
+ private boolean filter = true;
+ private boolean normalize = true;
+ private URLFilters filters = null;
+ private URLNormalizers normalizers = null;
+ private CrawlDatum datum = new CrawlDatum();
+ private SiteMapParser parser = null;
+
+ public void setup(Context context) {
+ Configuration conf = context.getConfiguration();
+ this.protocolFactory = new ProtocolFactory(conf);
+ this.filter = conf.getBoolean(SITEMAP_URL_FILTERING, true);
+ this.normalize = conf.getBoolean(SITEMAP_URL_NORMALIZING, true);
+ this.strict = conf.getBoolean(SITEMAP_STRICT_PARSING, true);
+ this.parser = new SiteMapParser(strict);
+
+ if (filter)
+ filters = new URLFilters(conf);
+ if (normalize)
+ normalizers = new URLNormalizers(conf, URLNormalizers.SCOPE_DEFAULT);
+ }
+
+ public void map(Text key, Writable value, Context context) throws
IOException, InterruptedException {
+ String url;
+
+ try {
+ if (value instanceof CrawlDatum) {
+ // If its an entry from CrawlDb, emit it. It will be merged in the
reducer
+ context.write(key, (CrawlDatum) value);
+ }
+ else if (value instanceof HostDatum) {
+ // For entry from hostdb, get sitemap url(s) from robots.txt, fetch
the sitemap,
+ // extract urls and emit those
+
+ // try different combinations of schemes one by one till we get
rejection in all cases
+ String host = key.toString();
+ if((url = filterNormalize("http://"; + host + "/")) == null &&
+ (url = filterNormalize("https://"; + host + "/")) == null &&
+ (url = filterNormalize("ftp://"; + host + "/")) == null &&
+ (url = filterNormalize("file:/" + host + "/")) == null) {
+ context.getCounter("Sitemap", "filtered_records").increment(1);
+ return;
+ }
+
+ BaseRobotRules rules =
protocolFactory.getProtocol(url).getRobotRules(new Text(url), datum, new
LinkedList<>());
+ List<String> sitemaps = rules.getSitemaps();
+ for(String sitemap: sitemaps) {
+ context.getCounter("Sitemap", "sitemaps_from_hostdb").increment(1);
+ generateSitemapUrlDatum(protocolFactory.getProtocol(sitemap),
sitemap, context);
+ }
+ }
+ else if (value instanceof Text) {
+ // For entry from sitemap urls file, fetch the sitemap, extract urls
and emit those
+ if((url = filterNormalize(key.toString())) == null) {
+ context.getCounter("Sitemap", "filtered_records").increment(1);
+ return;
+ }
+
+ context.getCounter("Sitemap", "sitemap_seeds").increment(1);
+ generateSitemapUrlDatum(protocolFactory.getProtocol(url), url,
context);
+ }
+ } catch (Exception e) {
+ LOG.warn("Exception for record " + key.toString() + " : " +
StringUtils.stringifyException(e));
+ }
+ }
+
+ /* Filters and or normalizes the input URL */
+ private String filterNormalize(String url) {
+ try {
+ if (normalizers != null)
+ url = normalizers.normalize(url, URLNormalizers.SCOPE_DEFAULT);
+
+ if (filters != null)
+ url = filters.filter(url);
+ } catch (Exception e) {
+ return null;
+ }
+ return url;
+ }
+
+ private void generateSitemapUrlDatum(Protocol protocol, String url,
Context context) throws Exception {
+ ProtocolOutput output = protocol.getProtocolOutput(new Text(url), datum);
+ ProtocolStatus status = output.getStatus();
+ Content content = output.getContent();
+
+ if(status.getCode() != ProtocolStatus.SUCCESS) {
+ // If there were any problems fetching the sitemap, log the error and
let it go. Not sure how often
+ // sitemaps are redirected. In future we might have to handle
redirects.
+ context.getCounter("Sitemap", "failed_fetches").increment(1);
+ LOG.error("Error while fetching the sitemap. Status code: " +
status.getCode() + " for " + url);
+ return;
+ }
+
+ AbstractSiteMap asm = parser.parseSiteMap(content.getContentType(),
content.getContent(), new URL(url));
+ if(asm instanceof SiteMap) {
+ SiteMap sm = (SiteMap) asm;
+ Collection<SiteMapURL> sitemapUrls = sm.getSiteMapUrls();
+
+ for(SiteMapURL sitemapUrl: sitemapUrls) {
+ // If 'strict' is ON, only allow valid urls. Else allow all urls
+ if(!strict || sitemapUrl.isValid()) {
+ String key = filterNormalize(sitemapUrl.getUrl().toString());
+ if (key != null) {
+ CrawlDatum sitemapUrlDatum = new CrawlDatum();
+ sitemapUrlDatum.setStatus(CrawlDatum.STATUS_SITEMAP);
+ sitemapUrlDatum.setScore((float) sitemapUrl.getPriority());
+
+ if(sitemapUrl.getChangeFrequency() != null) {
+ int fetchInterval = -1;
+ switch(sitemapUrl.getChangeFrequency()) {
+ case ALWAYS: fetchInterval = 1; break;
+ case HOURLY: fetchInterval = 3600; break; // 60*60
+ case DAILY: fetchInterval = 86400; break; // 60*60*24
+ case WEEKLY: fetchInterval = 604800; break; // 60*60*24*7
+ case MONTHLY: fetchInterval = 2592000; break; // 60*60*24*30
+ case YEARLY: fetchInterval = 31536000; break; //
60*60*24*365
+ case NEVER: fetchInterval = Integer.MAX_VALUE; break; //
Loose "NEVER" contract
+ }
+ sitemapUrlDatum.setFetchInterval(fetchInterval);
+ }
+
+ if(sitemapUrl.getLastModified() != null)
+
sitemapUrlDatum.setModifiedTime(sitemapUrl.getLastModified().getTime());
+
+ context.write(new Text(key), sitemapUrlDatum);
+ }
+ }
+ }
+ }
+ else if (asm instanceof SiteMapIndex) {
+ SiteMapIndex index = (SiteMapIndex) asm;
+ Collection<AbstractSiteMap> sitemapUrls = index.getSitemaps();
+
+ for(AbstractSiteMap sitemap: sitemapUrls) {
+ if(sitemap.isIndex()) {
+ generateSitemapUrlDatum(protocol, sitemap.getUrl().toString(),
context);
+ }
+ }
+ }
+ }
+ }
+
+ private static class SitemapReducer extends Reducer<Text, CrawlDatum, Text,
CrawlDatum> {
+ CrawlDatum sitemapDatum = null;
+ CrawlDatum originalDatum = null;
+
+ public void reduce(Text key, Iterable<CrawlDatum> values, Context context)
+ throws IOException, InterruptedException {
+ sitemapDatum = null;
+ originalDatum = null;
+
+ for (CrawlDatum curr: values) {
+ if(curr.getStatus() == CrawlDatum.STATUS_SITEMAP && sitemapDatum ==
null) {
+ sitemapDatum = new CrawlDatum();
+ sitemapDatum.set(curr);
+ }
+ else {
+ originalDatum = new CrawlDatum();
+ originalDatum.set(curr);
+ }
+ }
+
+ if(originalDatum != null) {
+ // The url was already present in crawldb. If we got the same url from
sitemap too, save
+ // the information from sitemap to the original datum. Emit the
original crawl datum
+ if(sitemapDatum != null) {
+ context.getCounter("Sitemap",
"existing_sitemap_entries").increment(1);
+ originalDatum.setScore(sitemapDatum.getScore());
Review comment:
- the [sitemap
spec](https://www.sitemaps.org/protocol.html#xmlTagDefinitions) defines "the
priority of this URL relative to other URLs on your site." That's different
from a global score as calculated by OPIC, page rank, etc.
- overwriting fetchInterval will make
[calculateLastFetchTime()](https://github.com/apache/nutch/blob/master/src/java/org/apache/nutch/crawl/AbstractFetchSchedule.java#L158)
return the wrong time when a page has been fetched
- overwriting the modified time breaks any if-modified-since handling.
See the discussion in
[NUTCH-1465](https://issues.apache.org/jira/browse/NUTCH-1465) on Jan 30-31,
2014. I was also wrong how to map these "concepts" from sitemaps to
Nutch-internal ones.
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> Support sitemaps in Nutch
> -------------------------
>
> Key: NUTCH-1465
> URL: https://issues.apache.org/jira/browse/NUTCH-1465
> Project: Nutch
> Issue Type: New Feature
> Components: parser
> Reporter: Lewis John McGibbney
> Assignee: Lewis John McGibbney
> Fix For: 1.14
>
> Attachments: NUTCH-1465-sitemapinjector-trunk-v1.patch,
> NUTCH-1465-trunk.v1.patch, NUTCH-1465-trunk.v2.patch,
> NUTCH-1465-trunk.v3.patch, NUTCH-1465-trunk.v4.patch,
> NUTCH-1465-trunk.v5.patch
>
>
> I recently came across this rather stagnant codebase[0] which is ASL v2.0
> licensed and appears to have been used successfully to parse sitemaps as per
> the discussion here[1].
> [0] http://sourceforge.net/projects/sitemap-parser/
> [1]
> http://lucene.472066.n3.nabble.com/Support-for-Sitemap-Protocol-and-Canonical-URLs-td630060.html
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