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https://issues.apache.org/jira/browse/NUTCH-566?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12539146
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Doug Cook commented on NUTCH-566:
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Hi Doğacan.
Thanks for following up. The issue has gotten a little more complicated since I
first posted it.
I recently found, while looking for something else, that this is a dup of
NUTCH-436. A solution for that has been committed.
Both solutions are incomplete, however. The problem with the fix for NUTCH-436
is that it is applied locally to DOMContentUtils, but the bug affects Nutch
globally anywhere links are extracted. In this sense my solution is superior
because it creates a central utility function for the workaround, and calls
that from all the places links are extracted (DOMContentUtils is the most
common, but there are also SWFParser, JSParseFilter, and TextParser).
The patch for Nutch 436 may be more complete in that it handles more cases than
my simple fix. My fix handles the most common (only) case I've seen in practice
(relative link beginning with '?'), and has the advantage of being simple, but
the patch for Nutch-436 handles things like relative links beginning with ';'.
I haven't had a chance to analyze them both to see which is more 'correct'
(probably Nutch-436) and merge the two solutions, if necessary.
I've been so swamped trying to get my product launched (it's a 1-person
company!) that I haven't had time to follow up on all the contributions I'd
like to make. Usually I get a fix working just well enough to fit my local
needs and then I have to move on to tackling the next bug. At this point I've
got hundreds of local fixes and improvements, some of which are probably useful
for the Nutch community... hopefully after I launch I'll have time both to
contribute some goodies back and also to pick up all the improvements that have
been made to the trunk since I branched my code...
-Doug
> Sun's URL class has bug in creation of relative query URLs
> ----------------------------------------------------------
>
> Key: NUTCH-566
> URL: https://issues.apache.org/jira/browse/NUTCH-566
> Project: Nutch
> Issue Type: Bug
> Components: fetcher
> Affects Versions: 0.8, 0.8.1, 0.9.0
> Environment: MacOS X and Linux (CentOS 4.5) both
> Reporter: Doug Cook
> Priority: Minor
> Attachments: RelativeURL.java
>
>
> I'm using 0.81, but this will affect all other versions as well.
> Relative links of the form "?blah" are resolved incorrectly. For example,
> with a base URL of http://www.fleurie.org/entreprise.asp, and a relative link
> of "?id_entrep=111", Nutch will resolve this pair to the link
> "http://www.fleurie.org/?id_entrep=111";. No such URL exists, and all browsers
> I tried will resolve the pair to
> "http://www.fleurie.org/entreprise.asp?id_entrep=111";.
> I tracked this down to what could be called a bug in Sun's URL class.
> According to Sun's spec, they parse the relative URL according to RFC 2396.
> But the original RFC for relative links was RFC 1808, and the two RFCs differ
> in how they handle relative links beginning with "?". Most browsers
> (Netscape/Mozilla, IE, Safari) implemented RFC 1808, and stuck with it (for
> compatibility and also because the behavior makes more sense). Apparently
> even the people that wrote RFC 2396 recognized that this was a mistake, and
> the specified behavior was changed in RFC 3986 to match what browsers do.
> For a discussion of this, see
> http://gbiv.com/protocols/uri/rev-2002/issues.html#003-relative-query
> Sun's URL implementation, however, still implements RFC2396, as far as I can
> tell, and is out of step with the rest of the world.
> This breaks link extraction on a number of sites.
> I implemented a simple workaround, which I'm attaching. It is a static method
> to create URLs which behaves exactly as new URL(URL base, String
> relativePath), and I use it as a drop-in replacement for that in
> DOMContentUtils, Javascript link extraction, etc. Obviously, it really only
> matters wherever links are extracted. I haven't included the calling code
> from DOMContentUtils, etc. because my local versions are largely rewritten,
> but it should be pretty obvious.
> I put it in the org.apache.nutch.net directory, but obviously feel free to
> move it to another place if you feel it belongs there!
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