Hacker News to Email

hn_email.rb

#!/usr/local/bin/ruby -rubygems

require 'open-uri'
require 'json'
require 'pony'

class Headline
  def initialize(title, title_url, points, 
                 comments, comments_url, time, time_units)
    @title = title
    @title_url = title_url
    @points = points
    @comments = comments
    @comments_url = comments_url
    @time = time
    @time_units = time_units
  end
  
  def to_s
    "#{@title} [#{@title_url}] - #{@time} #{@time_units} ago | " <<
      "#{@points} points\n#{@comments} comments [#{@comments_url}]\n\n" 
  end
end

def to_minutes(time, time_units)
  if !/^days?$/i.match(time_units).nil?
    return time * 1440
  elsif !/^hours?$/i.match(time_units).nil?
    return time * 60
  elsif !/^minutes?$/i.match(time_units).nil?
    return time
  else
    raise ArgumentError
  end
end

#get filters from command line arguments
filters = {}
begin
  ARGV.each_with_index do |arg, i|
    if arg == '-p' or arg == '-c'
      if ARGV[1].nil? or ARGV[i+1].match(/\d+,==|>=|<=|>|<$/).nil?
        raise ArgumentError
      end
      value, comparator = ARGV[i+1].split ','
      filters[arg == '-p' ? "points" : "comments"] = 
        ["%d", comparator, Integer(value)]
    elsif arg == '-t'
      if ARGV[1].nil? or ARGV[i+1].match(/\d+,==|>=|<=|>|<$/).nil?
        raise ArgumentError
      end
      time, unit, comparator = ARGV[i+1].split ','
      filters["time"] = ["%d", comparator, to_minutes(Integer(time), unit)]
    end
  end
rescue ArgumentError
  puts "Proper usage: $ ./hn_email.rb [filter options]\n" +
       "Filter options include a flag followed by a value, where the flag \n" +
       "identifies which field to filter on. Options include:\n" +
       "\t-p 'POINTS,[<[=] or >[=] or ==]'      -->  Article must have [<[=] " +
       "or >[=] or ==] POINTS points\n" +
       "\t                                         Examples: \"-p '250,>='\"" +
       " or \"-p '75,<='\"\n" +
       "\t-c 'COMMENTS,[<[=] or >[=] or ==]'    -->  Article must have [<[=] " + 
       "or >[=] or ==] COMMENTS comments\n" +
       "\t                                         Examples: \"-c '15,>='\"" +
       " or \"-c '0,=='\"\n" +
       "\t-t 'TIME,UNIT,[<[=] or >[=] or ==]'   -->  Article must have been " +
       " posted [<[=] or >[=] or ==] TIME UNITs ago\n" +
       "\t                                         Examples: \"-t '5,hour,>'" +
       "\" or \"-t '15,minute,<='\" or \"-t '2,day,=='\"\n" +
       "You can select any of these options for filtering.\nUsing no options " +
       "simply returns the front page of articles.\nMake sure to include " +
       "quotes around the value strings after the flags in order to capture " +
       "each character.\n"
  exit
end

#get front page HN article information as JSON
json = ''
open("http://api.ihackernews.com/page").each { |f| json << f }
articles = JSON.parse(json)['items']

#gather all headlines which meet filter requirements
headlines = []
articles.each do |a|
  points = a['points']
  comments = a['commentCount']
  begin
    time_ago = a['postedAgo'].match(/(.+) ago/).captures[0].split ' '
    time = to_minutes(Integer(time_ago[0]), time_ago[1])
  rescue NoMethodError, ArgumentError
    next
  end
  
  valid = true
  filters.each do |k, v|
    valid &&= eval("%d %s %d" % [v[0] % eval(k), v[1], v[2]])
  end
  
  if valid
    title = a['title']
    title_url = a['url']
    comments_url = 'http://news.ycombinator.com/item?id=%d' % a['id']
    
    headlines << Headline.new(title, title_url, points, comments,
                              comments_url, Integer(time_ago[0]), time_ago[1])
  end
end

#get email credentials from external file
credentials = {'email' => '', 'password' => '', 'address' => '', 'port' => ''}
File.open(File.join(File.dirname(__FILE__), 'credentials.txt'), 'r') do |f|  
  while line = f.gets
    credentials.each do |k, v|
      if !/^#{k}/.match(line).nil?
        credentials[k] = line.split(':')[1].strip
        next
      end
    end  
  end  
end

#email filtered HN headlines to self
Pony.mail(:to => credentials['email'], :via => :smtp, :via_options => {
    :address => credentials['address'],
    :port => credentials['port'],
    :enable_starttls_auto => true,
    :user_name => credentials['email'],
    :password => credentials['password'],
    :authentication => :plain,
},
:subject => 'HN to EM', :body => headlines)