forecast-view-simple.pl

#!/usr/bin/env perl
use strict;
use warnings;

#############################
# Getting the Forecast Data #
#############################

use PDL;
use Time::Piece;
my $current = localtime;
my $zip_code = shift @ARGV || '60601';

# pull the weather data from the web
my $dom_data = get_weather_data_for($zip_code);

# Pull out the temperatue data and convert to PDL
my $temp_data = $dom_data->at('temperature[type="hourly"]');
my @temps = $temp_data->find('value')
                      ->pluck('text')
                      ->each;
my $temp = pdl \@temps;


# get the times related to the temperature sequence, mapping them do days
# in the future, and convert to PDL
my $time_name = $temp_data->{'time-layout'};
my @times = $dom_data->find('time-layout')
                 ->first(sub{$_->at('layout-key')->text eq $time_name})
                 ->find('start-valid-time')
                 ->pluck('text')
                 ->map(\&convtime)
                 ->each;
my $time = pdl \@times;


#################
# Plot the data #
#################

use PDL::Graphics::Prima::Simple;
line_plot $time, $temp;

#####################################
# Web retrieval and date conversion #
#####################################

sub convtime {
  s/-\d{2}:\d{2}$//; # strip end time
  my $delta = Time::Piece->strptime($_, '%Y-%m-%dT%T') - $current;
  $delta->days;
}

use Mojo::UserAgent;
use Mojo::URL;

# Pull data for the requested zip code with a Mojo user agent
sub get_weather_data_for {
  my $zip_code = shift;
  my $ua = Mojo::UserAgent->new;
  my $url = Mojo::URL->new(
    'http://graphical.weather.gov/xml/sample_products/browser_interface/ndfdXMLclient.php'
  )->query(
    zipCodeList => $zip_code, 
    product     => 'time-series'
  );
  return $ua->get($url)->res->dom;
}