[nominatim-web] Use shortened arg_lon and arg_lat in upstream request

[Bartłomiej Piotrowski <bpiotrowski src gnome org>]

commit 4c794c459f114a0fd4a870741d5f5835072ee1d3
Author: Bartłomiej Piotrowski <bpiotrowski gnome org>
Date:   Tue May 26 23:35:38 2020 +0200

    Use shortened arg_lon and arg_lat in upstream request

 nginx.conf | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)
---
diff --git a/nginx.conf b/nginx.conf
index dd3950b..60edd5c 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -28,6 +28,7 @@ http {
     keepalive_timeout  65;
 
     #gzip  on;
+    rewrite_by_lua_no_postpone on;
 
     upstream nominatim {
         server nominatim-int.gnome.org:80;
@@ -75,11 +76,10 @@ http {
 
             proxy_pass http://nominatim/search;
             proxy_set_header Host "nominatim-int.gnome.org";
-            add_header X-Cache-Status $srcache_fetch_status;
         }
 
         location = /reverse {
-            set_by_lua_block $coord { 
+            rewrite_by_lua '
                 local shorten = function (str)
                     if string.sub(str,1,1) == "-" then
                         return string.sub(str,1,9)
@@ -89,13 +89,12 @@ http {
                 end
 
                 local args = ngx.req.get_uri_args()
-                local lat = shorten(args["lat"])
-                local lon = shorten(args["lon"])
+                args.lat = shorten(args.lat)
+                args.lon = shorten(args.lon)
+                ngx.req.set_uri_args(args)
+            ';
 
-                return lat .. "x" .. lon
-            }
-
-            set $cache_key reverse_$lang$coord;
+            set $cache_key "reverse_$lang${arg_lat}x${arg_lon}";
             srcache_fetch GET /redis-fetch $cache_key;
             srcache_store PUT /redis-store key=$cache_key;
             srcache_store_no_cache on;
@@ -103,7 +102,6 @@ http {
 
             proxy_pass http://nominatim/reverse;
             proxy_set_header Host "nominatim-int.gnome.org";
-            add_header X-Cache-Status $srcache_fetch_status;
         }
     }
 }