defp build_resp_cache_headers(headers, _opts) do
has_cache? = Enum.any?(headers, fn {k, _} -> k in @resp_cache_headers end)
-
- if has_cache? do
- headers
- else
- List.keystore(headers, "cache-control", 0, {"cache-control", @default_cache_control_header})
+ has_cache_control? = List.keymember?(headers, "cache-control", 0)
+
+ cond do
+ has_cache? && has_cache_control? ->
+ headers
+
+ has_cache? ->
+ # There's caching header present but no cache-control -- we need to explicitely override it to public
+ # as Plug defaults to "max-age=0, private, must-revalidate"
+ List.keystore(headers, "cache-control", 0, {"cache-control", "public"})
+
+ true ->
+ List.keystore(
+ headers,
+ "cache-control",
+ 0,
+ {"cache-control", @default_cache_control_header}
+ )
end
end