Add MedicalCheckAlertWorker

app/workers/medical_alert_check_worker.rb

@@ -0,0 +1,33 @@
+class MedicalAlertCheckWorker < ApplicationWorker
+  FEED_PATH = "/drug-device-alerts.atom".freeze
+  NUMBER_OF_ITEMS = 5
+
+  def perform
+    content_ids = valid_content_ids
+    delivered = 0
+    content_ids.each { |ci| delivered += 1 if any_emails_delivered_for?(ci) }
+
+    Rails.logger.info("Checking alerts: #{delivered} out of #{content_ids.count} alerts have been delivered to at least one recipient")
+
+    Rails.cache.write("current_medical_alerts", content_ids.count, expires_in: 30.minutes)
+    Rails.cache.write("delivered_medical_alerts", delivered, expires_in: 30.minutes)
+  end
+
+  def any_emails_delivered_for?(content_id)
+    Email.where(notify_status: "delivered", content_id:).exists?
+  end
+
+  def feed_url
+    Plek.website_root + FEED_PATH
+  end
+
+  def valid_content_ids
+    URI.parse(feed_url).open do |raw_rss|
+      RSS::Parser
+        .parse(raw_rss)
+        .items.first(NUMBER_OF_ITEMS)
+        .select { |entry| entry.updated.content < Time.zone.now - 3600 }
+        .map(&:dc_identifier)
+    end
+  end
+end