Ignore unknown country code

config/test.exs

@@ -27,7 +27,8 @@ config :geolix,
       adapter: Geolix.Adapter.Fake,
       data: %{
         {1, 1, 1, 1} => %{country: %{iso_code: "US"}},
-        {1, 1, 1, 1, 1, 1, 1, 1} => %{country: %{iso_code: "US"}}
+        {1, 1, 1, 1, 1, 1, 1, 1} => %{country: %{iso_code: "US"}},
+        {0, 0, 0, 0} => %{country: %{iso_code: "ZZ"}}
       }
     }
   ]

lib/plausible_web/controllers/api/external_controller.ex

@@ -385,7 +385,10 @@ defmodule PlausibleWeb.Api.ExternalController do
       PlausibleWeb.RemoteIp.get(conn)
       |> Geolix.lookup()
 
-    country_code = get_in(result, [:geolocation, :country, :iso_code])
+    country_code =
+      get_in(result, [:geolocation, :country, :iso_code])
+      |> ignore_unknown_country
+
     city_geoname_id = get_in(result, [:geolocation, :city, :geoname_id])
 
     subdivision1_code =
@@ -414,6 +417,9 @@ defmodule PlausibleWeb.Api.ExternalController do
     }
   end
 
+  defp ignore_unknown_country("ZZ"), do: nil
+  defp ignore_unknown_country(country), do: country
+
   @decorate trace("ingest.parse_referrer")
   defp parse_referrer(_, nil), do: nil
 

test/plausible_web/controllers/api/external_controller_test.exs

@@ -558,6 +558,22 @@ defmodule PlausibleWeb.Api.ExternalControllerTest do
       assert pageview.country_code == "US"
     end
 
+    test "ignores unknown country code ZZ", %{conn: conn} do
+      params = %{
+        name: "pageview",
+        domain: "external-controller-test-zz-country.com",
+        url: "http://gigride.live/"
+      }
+
+      conn
+      |> put_req_header("x-forwarded-for", "0.0.0.0")
+      |> post("/api/event", params)
+
+      pageview = get_event("external-controller-test-zz-country.com")
+
+      assert pageview.country_code == <<0, 0>>
+    end
+
     test "scrubs port from x-forwarded-for", %{conn: conn} do
       params = %{
         name: "pageview",