Sun's URL class has bug in creation of relative query URLs
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Key: NUTCH-566
URL: https://issues.apache.org/jira/browse/NUTCH-566
Project: Nutch
Issue Type: Bug
Components: fetcher
Affects Versions: 0.9.0, 0.8.1, 0.8
Environment: MacOS X and Linux (CentOS 4.5) both
Reporter: Doug Cook
Priority: Minor
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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