require 'nokogiri'
require 'open-uri'
# Bom Fetcher Module
# ------------------
# Fetches the locations from BoM or updates the location weather
# from BoM.
module BomFetcher
# The source name, and URL to fetch the data from.
SOURCE = "bom"
URL = "http://www.bom.gov.au/vic/observations/melbourne.shtml"
def self.get_location_dom
# Opens the HTML document (give it the URL of the HTML file)
doc = Nokogiri::HTML(open(URL))
# Fetches the DOM for the locations
return doc.css("#tMELBOURNE tbody tr")
end
# get_locations
# -------------
# Deletes all the current locations in the database (if any) and
# creates new records with the locations on the HTML page specified by
# the URL.
def self.get_locations
# Delete all locations from the db.
Location.delete_all
locations = get_location_dom
# For each location DOM, scrape the name and create a new
# location.
locations.each do |location|
name = location.css('th a').text
location = Location.new(name: name)
location.save
puts "Location #{name} successfully fetched"
end
end
# get_location_weather
# --------------------
# Scrapes the location weather data from the HTML page given by the URL.
def self.get_location_weather
locations = get_location_dom
# For each location DOM, scrape the relevant weather data and then store it
# into the database.
locations.each do |location|
# Initialise a weather data hash
weather_data = {}
# Get the name of the location
name = location.css('th a').text
# Get the tag of the location
location_tag = location.css('th')[0]["id"]
# Get the location data from the database
location_data = Location.where(name: name).first
# Set the weather data to the relevant values
weather_data[:time] = Time.current
weather_data[:date] = "#{weather_data[:time].day}-#{weather_data[:time].month}-#{weather_data[:time].year}"
weather_data[:curr_temp] = location.css("td").at("td[headers='obs-temp #{location_tag}']").text.to_f
weather_data[:dew_point] = location.css("td").at("td[headers='obs-dewpoint #{location_tag}']").text.to_f
weather_data[:rainfall] = Rainfall.from9am_mm_to_mmhr(location.css("td").at("td[headers='obs-rainsince9am #{location_tag}']").text.to_f)
weather_data[:wind_dir] = location.css("td").at("td[headers='obs-wind obs-wind-dir #{location_tag}']").text
weather_data[:wind_speed] = location.css("td").at("td[headers='obs-wind obs-wind-spd-kph #{location_tag}']").text.to_f
# Insert the weather data into the database
location_data.insert_weather_data(SOURCE, weather_data)
end
end
end
