=encoding utf8

=head1 NAME

YiJing::0x11 - Gu\/ (Web Crawler)

=head1 DESCRIPTION

"Beware: There is only a thin line between a crawler and a worm!"

=head2 Judgment

    蠱。元。亨。利涉大川。先甲三日。后甲三日。

Web crawler: Nice and fun.  Suitable to sift in the great Data Flow.
Test run for three days before sending it out; analyze the data for
three days before sending it out again.

=head2 Interpretation

    彖曰。蠱。剛上而柔下。巽而止。
	  蠱。元亨。而天下治也。利涉大川。往有事也。
	  先甲三日。后甲三日。終則有始。天行也。

This hexagram is emblematic of the trouble that you would face in
writing or managing a web crawler: the program has to strike out on its
own and unobtrusively sift great gobs of data in any number of messy
formats.

It needs testing and retesting, planning and monitoring. It has to
follow old standards and accept new ones, and tolerate sites that don't
follow standards at all. To do its work, the web crawler has to get as
much data from as many sites as it can, without bothering any webmasters
in the process.

It has to be efficient, but deliberate. It is a matter of contradictory
goals -- a situation that comes up in all sorts of systems besides web
crawlers.

=head2 Image

    象曰。山下有風。蠱。君子以振民育德。

Gathering Data under Standards,
is the Image of a Web Crawler.
A wise hacker makes careful use of it
to provide people with interesting information
while maintaining the proper ethics.

=head2 Lines

=over 4

=item *

    初六。干父之蠱。有子。考無咎。厲終吉。
    象曰。干父之蠱。意承考也。

Crawling and the Data.

... The web crawler will harvest some bad data.  Make sure it can
recover well and move on correctly.

=item *

    九二。干母之蠱。不可貞。
    象曰。干母之蠱。得中道也。

Crawling and the Network.

... The web crawler should back off from network trouble, wait,
compromise, and improvise.

=item *

    九三。干父小有晦。無大咎。
    象曰。干父之蠱。終無咎也。

Fine tuning.

... You'll have to fix some mistakes that shouldn't have been made, but
it's no big deal.

=item *

    六四。裕父之蠱。往見吝。
    象曰。裕父之蠱。往未得也。

Obvious and oblivious.

... The implementation is nice and simple, and dangerously wrong.  Watch
it upset everyone!

=item *

    六五。干父之蠱。用譽。
    象曰。干父之蠱。承以德也。

Public attention.

... Make it clear that you're listening to what people say.  The web
crawler depends on the kindness of strangers.

=item *

    上九。不事王侯。高尚其事。
    象曰。不事王侯。志可則也。

Stepping back.

... You should act on principle depite the authority's demands, so that
you can serve a higher goal.

=back

=cut
