Details
Major Description
I tried running Nutch on my Synology NAS. As SMB protocol is not contained in Nutch, I turned on FTP service on the NAS and configured Nutch to crawl ftp://nas.
The experience gives me varying results which seem to point to problems within Nutch. However this may need further evaluation.
As some files could not be downloaded and I could not see a good error message I changed the method org.apache.nutch.protocol.ftp.FTP.getProtocolOutput(Text, CrawlDatum) to not only return protocol status but send the full exception and stack trace to the logs:
{{ } catch (Exception e) {
LOG.warn("Could not get {}", url, e);
return new ProtocolOutput(null, new ProtocolStatus(e));
}
}}
With this modification I suddenly see such messages in the logfile:
{{2017-10-25 14:14:37,254 TRACE org.apache.nutch.protocol.ftp.Ftp - fetching ftp://nas/silver-sda2/home/vivi/Desktop/Pictures/Kenya%20Pics/
2017-10-25 14:14:37,512 WARN org.apache.nutch.protocol.ftp.Ftp - Could not get ftp://nas/silver-sda2/home/vivi/Desktop/Pictures/Kenya%20Pics/
org.apache.nutch.protocol.ftp.FtpError: Ftp Error: 404
at org.apache.nutch.protocol.ftp.Ftp.getProtocolOutput(Ftp.java:151)
at org.apache.nutch.fetcher.FetcherThread.run(FetcherThread.java:340)
}}
Please mind the URL was not configured from me. Instead it was obtained by crawling my NAS. Also the URL looks perfectly fine to me. Even more, using Firefox and the same authentication data on the same URL displays the directory successfully. Therefore I suspect the FTP client is unable to decode the URL such that the FTP server would understand it.