ActsAsScheduled
===============

Acts as Scheduled allows you to manage scheduling events for your models.

A good example of this is scheduling the update of RSS Feeds in a background process (Cron, BackgroundRB)

With acts_as_scheduled your schedule manager can simply call "Model.find_next_scheduled()" to grab the next item from the database.


Installation
============

** WORKS ONLY IN MYSQL ** 
       
All you need to get started is to add two extra columns to your table:

    t.integer frequency
    t.datetime last_scheduled 

frequency is the number of seconds for your schedule.
last_scheduled is the date and time the record was last processed.

Ruby on Rails is real smart with times, so you don't have to worry too much about calculating frequency values:

    model.frequency = 1.day
    model.frequency = 1.minute
    model.frequency = 10.second

In your model class your simply declare "acts_as_scheduled" and you now have two extra methods find_next_scheduled and schedule_complete.

    find_next_scheduled
    -------------------
    Returns the next scheduled record from the table.
    The next scheduled record is calculated as "the record who's last_scheduled value is less than the current time minus the specified frequency in seconds".

    Which is the complex way of saying "if freqency is 1 minute, return the record if it was last_scheduled more than 1 minute ago"

    If there is more than one record, records scheduled to occur more frequently will be handled first (so records with minute schedules are returned before records with daily schedules.

    schedule_complete
    -----------------
    Sets the record's last_scheduled value to Time.now


Example
=======

     schedule_minute = ScheduledItem.new(:frequency => 1.minute, :last_scheduled => 2.seconds.ago)
     schedule_minute.save
  
     schedule_day = ScheduledItem.new(:name =>"day", :frequency => 1.day, :last_scheduled => 25.hours.ago)
     schedule_day.save
  
     #returns thing_day because it was last_scheduled 25 hours ago
     schedule_day = ScheduledItem.find_next_scheduled
     schedule_day.do_some_stuff
     schedule_day.schedule_complete
     schedule_day.save

Copyright (c) 2008 Toby Hede (tobyhede@gmail.com), released under the MIT license