Optimize events listing

app/controllers/management/events_controller.rb

@@ -3,7 +3,7 @@ module Management
     def index
       @conference = find_conference
       @filters = params[:filters] || {}
-      @events = EventSearch.new(scope: Event.where(conference: @conference).eager_load(:proposition, :proposer, :track, :event_type), filters: params[:filters]).results
+      @events = EventSearch.new(scope: Event.where(conference: @conference).eager_load(:participants_with_personal_profiles, :proposition, :proposer, :track, :event_type).preload(:conference), filters: params[:filters]).results
       # @events = @conference.events.order(:title).includes(:proposition, :proposer, :track, :event_type)
     end
 

app/helpers/events_helper.rb

@@ -1,12 +1,11 @@
 module EventsHelper
   def links_to_event_participants_for(event)
-    event.participants.map do |participant|
-      if participant.personal_profile(event.conference).present?
-        profile = participant.personal_profile(event.conference)
-        link_to icon(:user, profile.name),
-          management_conference_personal_profile_path(profile, conference_id: event.conference.id)
+    event.participants_with_personal_profiles.map do |participant|
+      if participant.has_personal_profile?
+        link_to icon(:user, participant.name),
+          management_conference_personal_profile_path(participant.personal_profile_id, conference_id: event.conference.id)
       else
-        link_to icon('user-plus', participant.email),
+        link_to icon('user-plus', participant.personal_email),
           new_management_conference_personal_profile_path(conference_id: event.conference.id,
                                                           user_id: participant.id),
           title: t('management.events.event.create_profile'), class: 'bg-danger'

app/models/event.rb

@@ -9,6 +9,7 @@ class Event < ActiveRecord::Base
   has_many :pending_participations, ->() { pending }, class_name: 'Participation'
   has_many :approved_participations, ->() { approved }, class_name: 'Participation'
   has_many :participants, through: :approved_participations
+  has_many :participants_with_personal_profiles, through: :approved_participations, source: :participant_with_personal_profile
   has_many :conflict_counts, -> { order(number_of_conflicts: :desc) }, foreign_key: :left_id
 
   belongs_to :event_type
@@ -32,9 +33,7 @@ class Event < ActiveRecord::Base
   accepts_nested_attributes_for :participations, allow_destroy: true
 
   def all_participants_have_profiles?
-    participants.all? do |participant|
-      participant.personal_profile(conference).present?
-    end
+    participants_with_personal_profiles.all? { |participant| participant.has_personal_profile? }
   end
 
   def proposer_profile

app/models/participant.rb

@@ -0,0 +1,16 @@
+class Participant < ActiveRecord::Base
+  self.table_name = :participants
+  self.primary_key = :participant_id
+
+  def twitter=(handle)
+    write_attribute :twitter, handle.gsub(/\A@/,'') if handle
+  end
+
+  def name
+    "#{first_name} #{last_name}"
+  end
+
+  def has_personal_profile?
+    user_id.present?
+  end
+end

app/models/participation.rb

@@ -1,5 +1,6 @@
 class Participation < ActiveRecord::Base
   belongs_to :participant, class_name: User
+  has_one :participant_with_personal_profile, class_name: Participant
   belongs_to :event
   validates :participant_id, presence: true
   scope :approved, ->() { where approved: true }

db/migrate/20161015023007_add_participants_view.rb

@@ -0,0 +1,24 @@
+PARTICIPANTS_SQL = <<EOS
+CREATE VIEW "participants" AS
+SELECT "users"."id" AS "participant_id",
+       "users"."email" AS personal_email,
+       "users"."language" AS language,
+       "participations"."id" AS "participation_id",
+       "personal_profiles"."id" AS "personal_profile_id",
+       "personal_profiles".* FROM "users"
+INNER JOIN "participations"    ON "users"."id" = "participations"."participant_id"
+INNER JOIN "events"            ON "events"."id" = "participations"."event_id"
+INNER JOIN "conferences"       ON "events"."conference_id" = "conferences"."id"
+LEFT JOIN "personal_profiles"  ON "personal_profiles"."conference_id" = "events"."conference_id"
+                              AND "personal_profiles"."user_id" = "users"."id";
+EOS
+
+class AddParticipantsView < ActiveRecord::Migration
+  def up
+    execute PARTICIPANTS_SQL
+  end
+
+  def down
+    execute 'DROP VIEW "participants"'
+  end
+end