Question

Specifically: I have a Schedule model where a person cans schedule one event per day at the same time every day. Like this:

class Schedule

  include Mongoid::Document
  include Mongoid::Timestamps 

  field :hour,      :type => Integer, :default => 8
  field :ampm,      :type => String,  :default => "am"
  field :time_zone, :type => String,  :default => "Eastern Time (US & Canada)"

  field :monday,    :type => Boolean, :default => true
  field :wednesday, :type => Boolean, :default => true
  field :friday,    :type => Boolean, :default => true

  field :tuesday,   :type => Boolean, :default => false
  field :thursday,  :type => Boolean, :default => false
  field :saturday,  :type => Boolean, :default => false
  field :sunday,    :type => Boolean, :default => false

  embedded_in :user

end

I have a rake task that is run hourly and I just want to query for all schedules that require and event “now”. So for example if it is noon UTC on a Monday, then a schedule with :timezone => EST and :hour => 7 should be in the results as should a schedule with :timezone => PST and :hour => 4. This of course is a lot more tricky when it is, say, 1am UTC Tuesday because that is Monday in both PST/EST.

I thought about just normalizing the hour so everyone was on utc but this would create a mess for me with the days because someone might schedule something for 11pm wed which is actually thurs utc, so “normalization” would become a total pita where the days users select in their scheduler form wouldn’t correspond with the days we stored in the db.

I’m using mongoid in case anyone has a mongoid specific solution.

Answer 1

If it’s not an option to save the dates in UTC, you’ll have to query each time zone separately. Something like:

wdays = [:sunday, :monday, :tuesday, :wednesday, :thursday, :friday, :saturday]
now = Time.now
TimeZone.all.each { |time_zone|
  remote_time = now.in_time_zone(time_zone)
  schedules = Schedules.where(
    :time_zone => time_zone.name,
    :hour => remote_time.strftime("%-l").to_i,
    :ampm => remote_time.strftime("%P"),
    wdays[remote_time.wday] => true,
  )
  # process schedules
}