Inspired by frozenwithjoy, I played with it a little, arriving at
#!/usr/bin/perl -w
use XML::FeedPP;
use XML::LibXML;
use XML::Rules;
use LWP::Simple;
use strict;
use warnings;
# get the Atom feed from the USGS
my $source = 'http://earthquake.usgs.gov/earthquakes/feed/v1.0/summary
+/4.5_day.atom';
my $feed = XML::FeedPP->new( $source );
# Incorporating a rules section so that we can extract the information
+ from the CDATA section
# and any other specific fields we might need. First attempt will be
+to pull the 'Updated'
# field data from the Atom feed. I tried to follow the example in the
+ CPAN summary but I'm
# clearly lost.
my @rules = (
_default => sub {$_[0] => $_[1]->{_content}},
id => sub {$_[0] => $_[1]->{_content}},
# author => undef, # ignoring the author because I already know
+ it's the USGS
author => sub {$_[0] => $_[1]->{_content}},
updated => sub {print "$_[1]->{updated}\n";
},
);
my $parser = XML::Rules->new(rules => \@rules);
my $atom = $feed->to_string();
$parser->parse( $atom );
# This section extracts the title field, then performs string manipula
+tions to extract the
# long location data and the magnitude. Funny that USGS does not have
+ a magnitude field
# in this feed.
foreach my $quake( $feed->get_item() ) {
my $title = $quake->title();
my $place = substr($title, 8);
my $magnitude = substr($title, 2,3);
my $id = $quake->get( "id");
my $update = $quake->get( "updated" );
my $location = $quake->get( "georss:point");
print "Magnitude ", $magnitude, " about ", $place, "\n";
print "id is $id, updated at $update, georss:point is $location \n
+";
}
Running it,
C:\Users\jkeys>perl c:\myperl\usgsfeed_norules.pl
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Use of uninitialized value in concatenation (.) or string at c:\myperl
+\usgsfeed_norules.pl line 25.
Magnitude 4.9 about 67km SW of Painan, Indonesia
id is urn:earthquake-usgs-gov:us:c000hl79, updated at 2013-06-11T03:00
+:47.746Z, georss:point is -1.8063 100.1636
Magnitude 4.7 about 131km NNE of Calama, Chile
id is urn:earthquake-usgs-gov:us:c000hl5v, updated at 2013-06-11T03:13
+:17.731Z, georss:point is -21.3693 -68.4452
Magnitude 4.9 about Galapagos Triple Junction region
id is urn:earthquake-usgs-gov:us:c000hl36, updated at 2013-06-11T06:39
+:02.261Z, georss:point is 1.3674 -101.2936
Magnitude 5.0 about 75km ESE of Pangai, Tonga
id is urn:earthquake-usgs-gov:us:c000hl2w, updated at 2013-06-11T06:31
+:30.385Z, georss:point is -20.0901 -173.6971
Magnitude 4.9 about 71km SW of Paita, Peru
id is urn:earthquake-usgs-gov:us:c000hkbe, updated at 2013-06-10T22:23
+:52.275Z, georss:point is -5.5453 -81.5723
Magnitude 4.7 about 68km E of Sarangani, Philippines
id is urn:earthquake-usgs-gov:us:c000hk85, updated at 2013-06-10T19:54
+:48.457Z, georss:point is 5.2973 126.0703
Magnitude 4.6 about 60km WNW of Lata, Solomon Islands
id is urn:earthquake-usgs-gov:us:c000hk60, updated at 2013-06-10T16:28
+:39.451Z, georss:point is -10.4972 165.3268
This provides a few examples of accessors. I didn't attempt to dive into the rules, other than to comment out the $author => undef which quieted some of the uninitialized value warnings.
Hope this helps.
