Hi, Following on from my previous enquiry, I was told to send the URLs I was trying to crawl to be tried from your end. I sent these, but did not receive any confirmation of receipt. Can you please confirm if these have been received, and when I can look forward to getting some feedback?
I re-crawled the 20 URLs again and reset these values to the default values from the nutch-default.xml file: property> <name>fetcher.server.delay</name> <value>65.0</value> </property> <property> <name>fetcher.server.min.delay</name> <value>25.0</value> </property> <property> <name>fetcher.max.crawl.delay</name> <value>70</value> </property> I then set the ignore external links to false, as below: <property> <name>db.ignore.external.links</name> <value>false</value> </property> I set the following property to 'true' still: <property> <name>db.ignore.also.redirects</name> <value>true</value> <description>If true, the fetcher checks redirects the same way as links when ignoring internal or external links. Set to false to follow redirects despite the values for db.ignore.external.links and db.ignore.internal.links. </description> </property> 13 URLs were fetched, but of these, the URLs that were originally not fetched returned very few pages related to the domain in the URL, and this makes me question the crawl. Also, when external links are not ignored, the crawler does go off onto different sites, like Wikipedia, news sites, etc. This is hardly efficient as it spends so long on the crawl fetching irrelevant pages. How can this be controlled in Nutch? If crawling up to 900 URLs as we are going to be doing, will we have to write regex expressions for each URL in the regex-urlfilter in order to stick to the domains in the URL? There is no explicit documentation on how to do this in Nutch, unless I have missed it? Is there something that should be done that I'm not doing, or is Nutch just incapable of efficient crawling? Regards, Roseline When I crawled, Dr Roseline Antai Research Fellow Hunter Centre for Entrepreneurship Strathclyde Business School University of Strathclyde, Glasgow, UK [Small eMail Sig] The University of Strathclyde is a charitable body, registered in Scotland, number SC015263. From: Roseline Antai Sent: 13 December 2021 12:02 To: 'user@nutch.apache.org' <user@nutch.apache.org> Subject: Nutch not crawling all URLs Hi, I am working with Apache nutch 1.18 and Solr. I have set up the system successfully, but I'm now having the problem that Nutch is refusing to crawl all the URLs. I am now at a loss as to what I should do to correct this problem. It fetches about half of the URLs in the seed.txt file. For instance, when I inject 20 URLs, only 9 are fetched. I have made a number of changes based on the suggestions I saw on the Nutch forum, as well as on Stack overflow, but nothing seems to work. This is what my nutch-site.xml file looks like: <?xml version="1.0"?> <?xml-stylesheet type="text/xsl" href="configuration.xsl"?> <!-- Put site-specific property overrides in this file. --> <configuration> <property> <name>http.agent.name</name> <value>Nutch Crawler</value> </property> <property> <name>http.agent.email</name> <value>datalake.ng at gmail d</value> </property> <property> <name>db.ignore.internal.links</name> <value>false</value> </property> <property> <name>db.ignore.external.links</name> <value>true</value> </property> <property> <name>plugin.includes</name> <value>protocol-http|urlfilter-regex|parse-(html|tika)|index-(basic|anchor)|indexer-solr|scoring-opic|urlnormalizer-(pass|regex|basic)|language-identifier</value> </property> <property> <name>parser.skip.truncated</name> <value>false</value> <description>Boolean value for whether we should skip parsing for truncated documents. By default this property is activated due to extremely high levels of CPU which parsing can sometimes take. </description> </property> <property> <name>db.max.outlinks.per.page</name> <value>-1</value> <description>The maximum number of outlinks that we'll process for a page. If this value is nonnegative (>=0), at most db.max.outlinks.per.page outlinks will be processed for a page; otherwise, all outlinks will be processed. </description> </property> <property> <name>http.content.limit</name> <value>-1</value> <description>The length limit for downloaded content using the http:// protocol, in bytes. If this value is nonnegative (>=0), content longer than it will be truncated; otherwise, no truncation at all. Do not confuse this setting with the file.content.limit setting. </description> </property> <property> <name>db.ignore.external.links.mode</name> <value>byDomain</value> </property> <property> <name>db.injector.overwrite</name> <value>true</value> </property> <property> <name>http.timeout</name> <value>50000</value> <description>The default network timeout, in milliseconds.</description> </property> </configuration> Other changes I have made include changing the following in nutch-default.xml: property> <name>http.redirect.max</name> <value>2</value> <description>The maximum number of redirects the fetcher will follow when trying to fetch a page. If set to negative or 0, fetcher won't immediately follow redirected URLs, instead it will record them for later fetching. </description> </property> ************************************************************** <property> <name>ftp.timeout</name<ftp://ftp.timeout</name>> <value>100000</value> </property> <property> <name>ftp.server.timeout</name<ftp://ftp.server.timeout</name>> <value>150000</value> </property> ************************************************************* property> <name>fetcher.server.delay</name> <value>65.0</value> </property> <property> <name>fetcher.server.min.delay</name> <value>25.0</value> </property> <property> <name>fetcher.max.crawl.delay</name> <value>70</value> </property> I also commented out the line below in the regex-urlfilter file: # skip URLs containing certain characters as probable queries, etc. -[?*!@=] Nothing seems to work. What is it that I'm not doing, or doing wrongly here? Regards, Roseline Dr Roseline Antai Research Fellow Hunter Centre for Entrepreneurship Strathclyde Business School University of Strathclyde, Glasgow, UK [Small eMail Sig] The University of Strathclyde is a charitable body, registered in Scotland, number SC015263.