nginx＋ELBでhttps/http毎に行う処理を変えたい ref: http://qiita.com/kazuph/items/73777454375e6e4c235f

sample.conf

     location = / {
+        if ($http_x_forwarded_proto = "https") {
+            rewrite ^(.*) http://$server_name$1
+            break;
+        }
         ...
     }

     location / {
+        if ($http_x_forwarded_proto != "https") {
+            rewrite ^(.*) https://$server_name$1
+            break;
+        }