#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 %>
 
 location /
 {
   expires 1d;
+
+  # Redirect server/language root
+
+  rewrite ^/$ /$index_page last;
+  rewrite ^/(\w\w(_\w\w)?)$ /$1/ permanent;
+  rewrite ^/(\w\w(_\w\w)?)/$ /$1/$index_page last;
 
   # Match Accept-Language header against available languages
 
   set $preferredLang en;
   set $preferredRegion "";
   if ($http_accept_language ~ ^(\w\w)\b)
   {
     set $preferredLang $1;
   }
   if ($http_accept_language ~ ^\w\w-(\w\w)\b)
@@ skipping 14 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$1 last;
   }
-
-  # Redirect server/language root
-
-  rewrite ^/$ /$index_page last;
-  rewrite ^/(\w\w(_\w\w)?)$ /$1/ permanent;
-  rewrite ^/(\w\w(_\w\w)?)/$ /$1/$index_page last;
 }
 
-# http://hub.eyeo.com/issues/3299 Redirect missing translations to default
-location ~ ^/([a-z][a-z]\_[A-Z][A-Z])(/.+) {
+# 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 /es_Mx/page, redirect to /es/page instead:
-                rewrite ^/([a-z][a-z])\_([A-Z][A-Z])(/.+) /$1$3 redirect;
+    # 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])(/.+) {
+location ~ ^/([a-z][a-z])(/.+)
+{
   if (!-e "$document_root$uri")
   {
-    # if there is no /es/page, redirect to /page instead:
+    # 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 %>