#3299 - Add URI redirect for missing translations

modules/web/templates/site.conf.erb

 root /var/www/<%= @vhost %>;
 index index;
 default_type text/html;
 charset utf-8;
 
 set $index_page "index";
 
 <% if @custom_config %>
   <%= @custom_config %>
 <% end %>
@@ skipping 34 matching lines @@
     rewrite ^(.*) /${preferredLang}_$preferredRegion$1 last;
   }
   if (-e "$document_root/$preferredLang$uri")
   {
     rewrite ^(.*) /$preferredLang$1 last;
   }
   if (-e "$document_root/en$uri")
   {
     rewrite ^(.*) /en$1 last;
   }
+}
 
+# Redirect language URIs if no translations are found for the requested page
+
+location ~ ^/([a-z][a-z]\_[A-Z][A-Z])(/.+)
+{
+  if (!-e "$document_root$uri")
+  {
+    # if there is no language+region translation, try parent language URI
+    # example /es_MX/page -> /es/page
+    rewrite ^/([a-z][a-z])\_([A-Z][A-Z])(/.+) /$1$3 redirect;
+  }
+}
+
+location ~ ^/([a-z][a-z])(/.+)
+{
+  if (!-e "$document_root$uri")
+  {
+    # if there is no language translation, try canonical page for default language
+    # example /es/page -> /page
+    rewrite ^/([a-z][a-z])(/.+) $2 redirect;
+  }
 }
 
 <% if @multiplexer_locations %>
   <% @multiplexer_locations.each do |location| %>
   location <%= location %>
   {
     fastcgi_pass unix:/tmp/multiplexer-fastcgi.sock;
     include /etc/nginx/fastcgi_params;
   }
   <% end %>
 <% end %>