FEATURE: Custom unsubscribe options (#17090)

With this change, plugins can create custom unsubscribe keys, extend the unsubscribe view with custom preferences, and decide how they are updated.

app/controllers/email_controller.rb

@@ -6,38 +6,17 @@ class EmailController < ApplicationController
   skip_before_action :check_xhr, :preload_json, :redirect_to_login_if_required
 
   def unsubscribe
-    @not_found = true
-    @watched_count = nil
+    key = UnsubscribeKey.find_by(key: params[:key])
+    @found = key.present?
 
-    if key = UnsubscribeKey.find_by(key: params[:key])
-      if @user = key.user
-        post = key.post
-        @topic = post&.topic || key.topic
-        @digest_unsubscribe = !@topic && !SiteSetting.disable_digest_emails
-        @type = key.unsubscribe_key_type
-        @not_found = false
+    if @found
+      UnsubscribeKey
+        .get_unsubscribe_strategy_for(key)
+        &.prepare_unsubscribe_options(self)
 
-        if current_user.present? && (@user != current_user)
-          @different_user = @user.name
-          @return_url = request.original_url
-        end
-
-        watching = TopicUser.notification_levels[:watching]
-
-        @unsubscribed_from_all = @user.user_option.unsubscribed_from_all?
-
-        if @topic
-          @watching_topic = TopicUser.exists?(user_id: @user.id, notification_level: watching, topic_id: @topic.id)
-          if @topic.category_id
-            if CategoryUser.exists?(user_id: @user.id, notification_level: CategoryUser.watching_levels, category_id: @topic.category_id)
-              @watched_count = TopicUser.joins(:topic)
-                .where(user: @user, notification_level: watching, "topics.category_id" => @topic.category_id)
-                .count
-            end
-          end
-        else
-          @digest_frequencies = digest_frequencies(@user)
-        end
+      if current_user.present? && (@user != current_user)
+        @different_user = @user.name
+        @return_url = request.original_url
       end
     end
   end
@@ -46,80 +25,24 @@ class EmailController < ApplicationController
     RateLimiter.new(nil, "unsubscribe_#{request.ip}", 10, 1.minute).performed!
 
     key = UnsubscribeKey.find_by(key: params[:key])
-    raise Discourse::NotFound unless key && key.user
-
-    topic = key&.post&.topic || key.topic
+    raise Discourse::NotFound if key.nil? || key.user.nil?
     user = key.user
+    updated = UnsubscribeKey.get_unsubscribe_strategy_for(key)
+      &.unsubscribe(params)
 
-    updated = false
+    if updated
+      cache_key = "unsub_#{SecureRandom.hex}"
+      Discourse.cache.write cache_key, user.email, expires_in: 1.hour
 
-    if topic
-      if params["unwatch_topic"]
-        TopicUser.where(topic_id: topic.id, user_id: user.id)
-          .update_all(notification_level: TopicUser.notification_levels[:tracking])
-        updated = true
-      end
-
-      if params["unwatch_category"] && topic.category_id
-        TopicUser.joins(:topic)
-          .where(:user => user,
-                 :notification_level => TopicUser.notification_levels[:watching],
-                 "topics.category_id" => topic.category_id)
-          .update_all(notification_level: TopicUser.notification_levels[:tracking])
-
-        CategoryUser.where(user_id: user.id,
-                           category_id: topic.category_id,
-                           notification_level: CategoryUser.watching_levels
-                         )
-          .destroy_all
-        updated = true
-      end
-
-      if params["mute_topic"]
-        TopicUser.where(topic_id: topic.id, user_id: user.id)
-          .update_all(notification_level: TopicUser.notification_levels[:muted])
-        updated = true
-      end
-    end
-
-    if params["disable_mailing_list"]
-      user.user_option.update_columns(mailing_list_mode: false)
-      updated = true
-    end
-
-    if params['digest_after_minutes']
-      digest_frequency = params['digest_after_minutes'].to_i
-
-      user.user_option.update_columns(
-        digest_after_minutes: digest_frequency,
-        email_digests: digest_frequency.positive?
-      )
-      updated = true
-    end
-
-    if params["unsubscribe_all"]
-      user.user_option.update_columns(email_digests: false,
-                                      email_level: UserOption.email_level_types[:never],
-                                      email_messages_level: UserOption.email_level_types[:never],
-                                      mailing_list_mode: false)
-      updated = true
-    end
-
-    unless updated
-      redirect_back fallback_location: path("/")
-    else
-
-      key = "unsub_#{SecureRandom.hex}"
-      Discourse.cache.write key, user.email, expires_in: 1.hour
-
-      url = path("/email/unsubscribed?key=#{key}")
-      if topic
-        url += "&topic_id=#{topic.id}"
+      url = path("/email/unsubscribed?key=#{cache_key}")
+      if key.associated_topic
+        url += "&topic_id=#{key.associated_topic.id}"
       end
 
       redirect_to url
+    else
+      redirect_back fallback_location: path("/")
     end
-
   end
 
   def unsubscribed
@@ -130,31 +53,4 @@ class EmailController < ApplicationController
     topic = Topic.find_by(id: params[:topic_id].to_i) if @topic_id
     @topic = topic if topic && Guardian.new(nil).can_see?(topic)
   end
-
-  private
-
-  def digest_frequencies(user)
-    frequency_in_minutes = user.user_option.digest_after_minutes
-    email_digests = user.user_option.email_digests
-    frequencies = DigestEmailSiteSetting.values.dup
-    never = frequencies.delete_at(0)
-    allowed_frequencies = %w[never weekly every_month every_six_months]
-
-    result = frequencies.reduce(frequencies: [], current: nil, selected: nil, take_next: false) do |memo, v|
-      memo[:current] = v[:name] if v[:value] == frequency_in_minutes && email_digests
-      next(memo) unless allowed_frequencies.include?(v[:name])
-
-      memo.tap do |m|
-        m[:selected] = v[:value] if m[:take_next] && email_digests
-        m[:frequencies] << [I18n.t("unsubscribe.digest_frequency.#{v[:name]}"), v[:value]]
-        m[:take_next] = !m[:take_next] && m[:current]
-      end
-    end
-
-    result.slice(:frequencies, :current, :selected).tap do |r|
-      r[:frequencies] << [I18n.t("unsubscribe.digest_frequency.#{never[:name]}"), never[:value]]
-      r[:selected] ||= never[:value]
-      r[:current] ||= never[:name]
-    end
-  end
 end