Demo App for Fremont Consulting

demo.rb

require 'rubygems'
require 'sinatra/base'
require 'mongomapper'
require 'faker'

MongoMapper.database = 'demo'

# MongoMapper Model with fields defined.
class RandomRecord
  include MongoMapper::Document

  key :name, String
  key :timestamp, Float
  key :random_number, Float
end

class FremontConsultingDemo < Sinatra::Base

  get "/" do
    <<-OUTPUT
      Please Select a Link: <br /><br />
      <ol>
        <li><a href="/generate">Generate Data (and clear current data)</a></li>
        <li><a href="/average">Average all random numbers</a></li>
        <li><a href="/sum">Sum all random numbers</a></li>
        <li><a href="/update_timestamps">Iterate over all records and update the timestamp</a></li>
        <li><a href="http://gist.github.com/249283">See the code</a>
      </ol>
    OUTPUT
  end

  get "/generate" do
    # Empty current database
    RandomRecord.collection.clear

    # Loop 100 times and collect the return string of each iteration
    100.times.collect do
      # Create a new record with a fake name, current time, and a random float
      record = RandomRecord.create(
          {:name => Faker::Name.name,
           :timestamp => Time.now.to_f,
           :random_number => rand * 1000}
      )

      # Output the record in a nice format
      "Record Generated: #{record.to_json}"
    end.join("<br /><br />")
  end

  get "/average" do
    # Retrieve only the random_number fields and collect the data into an array
    "The Average of all the random_numbers in the database is: " + 
    (RandomRecord.all(:fields => [:random_number]).collect do |record|
      record.random_number
    # inject takes an initial sum, and then sets the sum to whatever the current 
    # iteration returns, thus sum and average is accomplished easily
    end.inject(0.0) {|sum, number| sum + number} / RandomRecord.count).to_s
  end

  get "/sum" do
    # Retrieve only the random_number fields and collect the data into an array
    "The Sum of all the random_numbers in the database is: " + 
    RandomRecord.all(:fields => [:random_number]).collect do |record|
      record.random_number
    # Inject to get the sum easily
    end.inject(0.0) {|sum, number| sum + number}.to_s
  end

  get "/update_timestamps" do
    RandomRecord.all.collect do |record|
      record.timestamp = Time.now.to_f
      record.save
      "Record Updated: #{record.to_json}"
    end.join("<br /><br />")
  end
end