Get the Probability of Precipitation from Weather Service REST API

gistfile1.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'rest_client'
require 'rexml/document'

def getHourProbPrecip(zipcodes_array)
  zipcodes_str = zipcodes_array.join('+')
  results = {}

  # Note: I set this time internal to this function and the way I do because
  # the web service returns probability of precipiation in 12 hour increments
  # 12 hours. Therefore it returns two values when the start and end date
  # and times differ greater than 4 hours. Since, the code below only parses
  # one value and assumes there is one value I am simplifying the function
  # by not having the begin_time and end_time be parameters.
  begin_time = Time.new().utc()
  end_time = begin_time
  
  # Define the start and end date and time to get the forcast for.
  s_datetime = begin_time.strftime('%Y-%m-%dT%H:%M:%S')
  e_datetime = end_time.strftime('%Y-%m-%dT%H:%M:%S')
  
  puts s_datetime.inspect
  puts e_datetime.inspect
  
  # Build the propery request URL for the national weather services REST API.
  weather_url = "http://www.weather.gov/forecasts/xml/sample_products/browser_interface/ndfdXMLclient.php?zipCodeList=#{zipcodes_str}&product=time-series&begin=#{s_datetime}&end=#{e_datetime}&pop12=pop12"

  res = RestClient.get weather_url
  puts res
  doc, posts = REXML::Document.new(res), []
  
  puts "Getting location keys"
  i = 0
  doc.elements.each('dwml/data/location') do |loc|
    puts i.inspect
    loc.elements.each('location-key') do |lk|
      puts zipcodes_array[i].inspect
      results[zipcodes_array[i]] = {}
      results[zipcodes_array[i]].merge!({ :location_key => lk.text })
      puts results[zipcodes_array[i]].inspect
    end
    i = i + 1
  end
  puts results.inspect
  
  puts "Getting prob of precipitations"
  z = 0
  doc.elements.each('dwml/data/parameters/probability-of-precipitation/value') do |prob|
    puts z.inspect
    results[zipcodes_array[z]].merge!({ :prob_perc => prob.text })
    puts results[zipcodes_array[z]].inspect
    z = z + 1
  end
  puts results.inspect
  
  return results
end

# Query the database via the locations table and group by postal to get a
# listing of lat lon pairs for each of the zip codes.

# zipcodes = '20910+25414'
zipcodes = ['92845', '90720']

foo = getHourProbPrecip(zipcodes)
foo.each { |k,v|
  puts "ZipCode: #{k}"
  puts "\tLocation Key: #{v[:location_key]}"
  puts "\tProb Precipitation: #{v[:prob_perc]}"
}