FIX: return an empty result if response from Amazon is missing expected attributes (#13173)

* FIX: return an empty result if response from Amazon is missing attributes

Check we have the basic attributes requires to construct a Onebox for Amazon.

This is an attempt to handle scenarios where we receive a valid 200-status response from an Amazon request that does not include the data we’re expecting.

* Update lib/onebox/engine/amazon_onebox.rb

Co-authored-by: Régis Hanol <regis@hanol.fr>

Co-authored-by: Régis Hanol <regis@hanol.fr>

lib/onebox/engine/allowlisted_generic_onebox.rb

@@ -66,6 +66,10 @@ module Onebox
         to_html
       end
 
+      def verified_data
+        data
+      end
+
       def data
         @data ||= begin
           html_entities = HTMLEntities.new

lib/onebox/engine/amazon_onebox.rb

@@ -46,6 +46,37 @@ module Onebox
         end
       end
 
+      def to_html(ignore_errors = false)
+        unless ignore_errors
+          verified_data # forces a check for missing fields
+          return '' unless errors.empty?
+        end
+
+        super()
+      end
+
+      def placeholder_html
+        to_html(true)
+      end
+
+      def verified_data
+        @verified_data ||= begin
+          result = data
+
+          required_tags = [:title, :description]
+          required_tags.each do |tag|
+            if result[tag].blank?
+              errors[tag] ||= []
+              errors[tag] << 'is blank'
+            end
+          end
+
+          result
+        end
+
+        @verified_data
+      end
+
       private
 
       def has_cached_body

lib/onebox/preview.rb

@@ -40,6 +40,11 @@ module Onebox
       engine.data
     end
 
+    def verified_data
+      return {} unless engine
+      engine.verified_data
+    end
+
     def options
       OpenStruct.new(@options)
     end