icalendar source sync: create/update/delete ical events

app/controllers/api/i_calendar_controller.rb

@@ -36,8 +36,7 @@ class API::ICalendarController < API::ApiController
   end
 
   def sync
-    worker = ICalendarImportWorker.new
-    worker.perform([params[:id]])
+    ICalendarImportWorker.perform_async([params[:id]])
     render json: { processing: [params[:id]] }, status: :created
   end
 

app/models/i_calendar_event.rb

@@ -3,4 +3,10 @@
 # iCalendar (RFC 5545) event, belonging to an ICalendar object (its source)
 class ICalendarEvent < ActiveRecord::Base
   belongs_to :i_calendar
+
+  def self.update_or_create_by(args, attributes)
+    obj = find_or_create_by(args)
+    obj.update(attributes)
+    obj
+  end
 end

app/services/i_calendar_import_service.rb

@@ -7,25 +7,29 @@ class ICalendarImportService
     require 'uri'
     require 'icalendar'
 
-    events = []
+    uids = []
 
     i_cal = ICalendar.find(i_calendar_id)
     ics = Net::HTTP.get(URI.parse(i_cal.url))
     cals = Icalendar::Calendar.parse(ics)
 
+    # create new events and update existings
     cals.each do |cal|
       cal.events.each do |evt|
-        events.push(
-          uid: evt.uid,
+        uids.push(evt.uid.to_s)
+        ICalendarEvent.update_or_create_by(
+          { uid: evt.uid.to_s },
+          {
             dtstart: evt.dtstart,
             dtend: evt.dtend,
             summary: evt.summary,
             description: evt.description,
             i_calendar_id: i_calendar_id
+          }
         )
       end
     end
-
-    ICalendarEvent.create!(events)
+    # remove deleted events
+    ICalendarEvent.where(i_calendar_id: i_calendar_id).where.not(uid: uids).destroy_all
   end
 end