2014-12-13

Sometimes, it is really nice to know what the weather is like without having to look out a window. Similarly, it is nice to know what the weather will be like in the future. Fortunately, getting weather information isn't that difficult.

For my needs, I wanted to get the weather data for a few cities in the Golden State, and have the data spoken to me by a computer.

For accessing the weather data, I headed over to http://api.wunderground.com/weather/api/ and signed up for a free API account. The free account limits me to 500 API calls per day and 10 calls per minutes. Since I am only interested in getting weather data a few times a week, the limits for the free account are of no real concern.

After getting my API key, it was time to fire up geany and smash out some Ruby code to do what I need to do, which is:

  • get the data from the API
  • save the data in a file
  • transform the data into a more speakable string
  • speak the string!

Enter the Ruby

#!/usr/bin/env ruby
require 'open-uri'
require 'json'
require 'fileutils'

key='########'
city=ARGV[0]
forecast_num ARGV[1].to_i || 0

#was city defined?
unless city
  puts 'you must enter a city name (or zip code)'
  exit()
end

#define some file locations
this_dir File.dirname(__FILE__)
data_file File.join(this_dir"#{city}.json")
temp_file data_file+".tmp"
#if the data file doesn't exist or it is more than an hour old
if not File.exists?(data_fileor File.mtime(data_file) < Time.now() - (1/24.0)
  #we need to dowload fresh data
  url="http://api.wunderground.com/api/#{key}/forecast/q/CA/#{city}.json"
  uri URI.parse(url)
  begin
    #read the text
    txt uri.read
    #write to the temp file
    open(temp_file"w"do |f|
      f.puts txt
    end
    #mv the temp file, clobber if necessary
    FileUtils.mv(temp_filedata_file:force => true)
  rescue
    puts "Failed to get weather data"
  end
    
end
#process the text from the data_file
txt IO.read(data_file)
weather JSON.parse(txt)
forecasts weather['forecast']['txt_forecast']['forecastday']
title forecasts[forecast_num]['title']
forecast forecasts[forecast_num]['fcttext']
#do some regex processing of the forecast
forecast forecast.gsub(/mph/"miles per hour")
forecast forecast.gsub(/([0-9]+)F/'\1 Fahrenheit')
#remove any %20 from  the city
city city.gsub(/%20/,' ')
string = (forecast_num.zero?) ? "" "Forecast "
string += "for #{city}#{title}#{forecast}"

#speak the string
`speak_string "#{string}"`

#comply with Section 2(d) @ http://www.wunderground.com/weather/api/d/terms.html
puts "This data is from Wunderground.com"

Just to make it a bit easier for me to get the weather or the forecast, this script is running on Cronos (my Minnowboard Max voice input machine) and is triggered via Blather when I say "what is the weather" or "what is the forecast". SWEET SAUCE!

Oh, the script references a command named "speak_string" which is a very simple wrapper for Festival and it looks like

#!/bin/sh
echo "$1" | festival --tts

Now quite reading, and go talk to a computer.... or look out the window and see some weather.

Comments
2014-12-31 Alison Chaiken:
Hmm, on Debian Testing my installation of festival doesn't know about any voices. I installed some voices (odd thing to say!) but it still complains it can't find its default voice. There doesn't appear to be a relevant setting in /etc, and the man page offers no clues. Have you configured Festival somehow? I used to run it, but apparently not recently.
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