Question

In my Ruby on Rails application I am building a calendar with Fullcalendar JQuery plugin for the views and using the Icecube gem to calculate event recurrence. I also use Thinking Sphinx for search.

The users can have many calendars each with their own set of recurring events. Currently this requires me to have to load all of the users calendars, and all of the calendar events. Then I have to calculate all of the event occurrences that take place within a certain month.

I’d like to cache the calculating of the occurrences taking place, and was thinking I could serialize an array of the occurrences within an events db column.

Then I would only need to load the users calendars, and any of the events that have an occurrence within the month.

I’m not sure how or even if I can get Thinking Sphinx to search a serialized array though. Is this possible, and how would I define that in my models define_index block?

Is there a more efficient way that I can cache / search event occurrence times? Or is there any other solutions people have used to solve a similar issue of searching Arrays of Time objects?

Answer 1

The trick to getting Sphinx to be able to search the cached occurrences was to use a comma separated list of timestamps. This allows you to define an index of a :multi type like so:

define_index do
  indexes :description
  indexes :name, :sortable => true
  indexes :location, :sortable => true
  has :calendar_id
  has :client_id
  has :end_at
  has :start_at
  has "calendar_events.occurrence_cache", :as => :occurrence_cache, :type => :multi 
  set_property :delta => true
end

Note that it’s important to use the table name when defining the multi type otherwise I wasn’t getting any results returned.

Now I can just use a sphinx scope to only find events with an occurrence within a timestamp range rather than having to load them all and determine their occurrences.

sphinx_scope(:ts_by_occurrence_at) do |occurrence_at_or_range|
  {:with => {:occurrence_cache => occurrence_at_or_range}}
end