email notifier via im.kayac.com

im.kayac.rb

#!/usr/bin/env ruby
#
# Read standard input or a file specified by the argument and notify devices
# via im.kayac.com.
#
# Usage:
#
# echo 'something' | $0 -u user_name -s secret
# $0 -u user_name -p password text_file
#
# Copyright 2012 by Shintaro Kojima. Released under an MIT license.
#

Version = '1.0'

require 'digest/sha1'
require 'json'
require 'mail'
require 'net/http'
require 'optparse'


#
# Class which generates and send messages to im.kayac.com via http API.
# (see also: im.kayac.com)
#
# == Usage
#
# Im.Kayac.new(:user => 'username', :secret => 'string',
#              :message => 'something').send
# Im.Kayac.new(:user => 'username', :secret => 'string').send('other')
# Im.Kayac.send('something', :to => 'username', :secret => 'string')
#
module Im
  module Kayac
    URL = 'http://im.kayac.com/api/post/%s'

    class Message
      attr_accessor :options

      def initialize(options={})
        raise ArgumentError.new("username for the API is not specified") unless options[:user]
        @data = { message: options.delete(:message) }
        @options = options
      end

      def send(string=nil)
        @data[:message] = string if string
        compose
        post
      end

      def self.send(message, options={})
        options[:message] = message
        options[:user] = options.delete(:to)
        message = new(options).send
      end


      private

      def compose
        add_digest
        add_password
        @data
      end

      def add_digest
        if @options[:secret]
          @data[:sig] = Digest::SHA1.hexdigest(@data[:message].to_s + @options[:secret].to_s)
        end
        @data
      end

      def add_password
        if @options[:password] and @data[:sig].nil?
          @data[:password] = @options[:password]
        end
        @data
      end

      def post
        response = Net::HTTP.post_form( URI(URL % @options[:user]), @data )
        case response
        when Net::HTTPSuccess, Net::HTTPRedirection
          result = JSON.parse(response.body)
          raise RuntimeError.new(result['error']) unless result['result'] == 'posted'
        else
          response.value
        end
      end
    end
  end
end


def init
  parser = OptionParser.new
  options = {}

  parser.on('-q', '--quiet', 'do not write anything to standard output'){|v| options[:quiet] = true }
  parser.on('-u', '--user==VAL', 'user name for HTTP API')              {|v| options[:to] = v }
  parser.on('-p', '--password==VAL', 'password for HTTP API')           {|v| options[:password] = v }
  parser.on('-s', '--secret==VAL', 'secret key string for SHA1 hash')   {|v| options[:secret] = v }

  begin
    parser.parse! ARGV
  rescue
    abort parser.help
  end

  options
end


#
# main
#

options =  init
begin
  src = Mail.read_from_string($<.read)
  Im::Kayac::Message.send "From: #{src.from && src.from.join(', ')}\n\n#{src.subject}",
                          options.select{|key, value| [:to, :password, :secret].include? key }
rescue
  raise $! unless options[:quiet]
end