Feature/event hosts (#1049)

- adds event_host migration and model
- an event can now accept nested attributes for its host
- updates to the event create form to accept and pass its host type and
id

Author: rsmithlal

app/controllers/better_together/events_controller.rb

@@ -8,6 +8,8 @@ class EventsController < FriendlyResourceController
       Rails.application.eager_load!
     end
 
+    before_action :build_event_hosts, only: :new
+
     def index
       @draft_events = @events.draft
       @upcoming_events = @events.upcoming
@@ -16,6 +18,29 @@ def index
 
     protected
 
+    def build_event_hosts # rubocop:disable Metrics/AbcSize
+      return unless params[:host_id].present? && params[:host_type].present?
+
+      return unless event_host_class
+
+      policy_scope = Pundit.policy_scope!(current_user, event_host_class)
+      host_record = policy_scope.find_by(id: params[:host_id])
+      return unless host_record
+
+      resource_instance.event_hosts.build(
+        host_id: params[:host_id],
+        host_type: params[:host_type]
+      )
+    end
+
+    def event_host_class
+      param_type = params[:host_type]
+
+      # Allow-list only specific classes to be set as host for an event
+      valid_host_types = BetterTogether::HostsEvents.included_in_models
+      valid_host_types.find { |klass| klass.to_s == param_type }
+    end
+
     def resource_class
       ::BetterTogether::Event
     end

app/helpers/better_together/events_helper.rb

@@ -3,5 +3,12 @@
 module BetterTogether
   # View helpers for events
   module EventsHelper
+    # Return hosts for an event that the current user is authorized to view.
+    # Keeps view markup small and centralizes the policy logic for testing.
+    def visible_event_hosts(event)
+      return [] unless event.respond_to?(:event_hosts)
+
+      event.event_hosts.map { |eh| eh.host if policy(eh.host).show? }.compact
+    end
   end
 end

app/models/better_together/community.rb

@@ -4,13 +4,14 @@ module BetterTogether
   # A gathering
   class Community < ApplicationRecord
     include Contactable
-    include Host
+    include HostsEvents
     include Identifier
     include Infrastructure::BuildingConnections
     include Joinable
+    include Permissible
+    include PlatformHost
     include Protected
     include Privacy
-    include Permissible
     include Metrics::Viewable
 
     belongs_to :creator,

app/models/better_together/event.rb

@@ -7,17 +7,19 @@ class Event < ApplicationRecord
     include Categorizable
     include Creatable
     include FriendlySlug
+    include Identifier
     include Geography::Geospatial::One
     include Geography::Locatable::One
-    include Identifier
+    include Metrics::Viewable
     include Privacy
     include TrackedActivity
-    include Viewable
 
     attachable_cover_image
 
     categorizable(class_name: 'BetterTogether::EventCategory')
 
+    has_many :event_hosts
+
     # belongs_to :address, -> { where(physical: true, primary_flag: true) }
     # accepts_nested_attributes_for :address, allow_destroy: true, reject_if: :blank?
     # delegate :geocoding_string, to: :address, allow_nil: true
@@ -27,11 +29,14 @@ class Event < ApplicationRecord
     translates :description, backend: :action_text
 
     validates :name, presence: true
-    validates :starts_at, presence: true
     validates :registration_url, format: { with: URI::DEFAULT_PARSER.make_regexp(%w[http https]) }, allow_blank: true,
                                  allow_nil: true
     validate :ends_at_after_starts_at
 
+    before_validation :set_host
+
+    accepts_nested_attributes_for :event_hosts, reject_if: :all_blank
+
     scope :draft, lambda {
       start_query = arel_table[:starts_at].eq(nil)
       where(start_query)
@@ -52,11 +57,18 @@ def self.permitted_attributes(id: false, destroy: false)
         starts_at ends_at registration_url
       ] + [
         {
-          address_attributes: BetterTogether::Address.permitted_attributes(id: true)
+          address_attributes: BetterTogether::Address.permitted_attributes(id: true),
+          event_hosts_attributes: BetterTogether::EventHost.permitted_attributes(id: true)
         }
       ]
     end
 
+    def set_host
+      return if event_hosts.any?
+
+      event_hosts.build(host: creator)
+    end
+
     def schedule_address_geocoding
       return unless should_geocode?
 

app/models/better_together/event_host.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+module BetterTogether
+  # Join an event to its host
+  class EventHost < ApplicationRecord
+    belongs_to :event, class_name: 'BetterTogether::Event'
+    belongs_to :host, polymorphic: true
+
+    def self.permitted_attributes(id: false, destroy: false)
+      super + %i[
+        host_id host_type event_id
+      ]
+    end
+  end
+end

app/models/better_together/person.rb

@@ -12,6 +12,7 @@ def self.primary_community_delegation_attrs
     include Author
     include Contactable
     include FriendlySlug
+    include HostsEvents
     include Identifier
     include Identity
     include Member
@@ -101,6 +102,10 @@ def description_html(locale: I18n.locale)
       super || description
     end
 
+    def valid_event_host_ids
+      [id] + member_communities.pluck(:id)
+    end
+
     def handle
       slug
     end

app/models/better_together/platform.rb

@@ -5,7 +5,7 @@
 module BetterTogether
   # Represents the host application and it's peers
   class Platform < ApplicationRecord
-    include Host
+    include PlatformHost
     include Identifier
     include Joinable
     include Permissible

app/models/concerns/better_together/hosts_events.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+module BetterTogether
+  # Concern that when included gives the model access to events through event_host records
+  # This module must be included in a model to permit assigning instances as an event host
+  module HostsEvents
+    extend ActiveSupport::Concern
+
+    included do
+      has_many :event_hosts, as: :host
+      has_many :hosted_events, through: :event_hosts, source: :event
+    end
+
+    def self.included_in_models
+      included_module = self
+      Rails.application.eager_load! if Rails.env.development? # Ensure all models are loaded
+      ActiveRecord::Base.descendants.select { |model| model.included_modules.include?(included_module) }
+    end
+  end
+end

…/models/concerns/better_together/host.rb …oncerns/better_together/platform_host.rbapp/models/concerns/better_together/host.rb renamed to app/models/concerns/better_together/platform_host.rb app/models/concerns/better_together/host.rb renamed to app/models/concerns/better_together/platform_host.rb

@@ -2,7 +2,7 @@
 
 module BetterTogether
   # Concern that when included allows model to be set as host
-  module Host
+  module PlatformHost
     extend ActiveSupport::Concern
 
     included do

app/policies/better_together/community_policy.rb

@@ -22,6 +22,11 @@ def update?
       user.present? && (permitted_to?('manage_platform') || permitted_to?('update_community', record))
     end
 
+    def create_events?
+      update? &&
+        BetterTogether::EventPolicy.new(user, BetterTogether::Event.new).create?
+    end
+
     def edit?
       update?
     end