From 666a08c46e2690f4564a12bc8f1dd650471195ac Mon Sep 17 00:00:00 2001
From: swrup <swrup@protonmail.com>
Date: Thu, 12 Feb 2026 12:45:07 +0100
Subject: [PATCH]

---
 src/headers.ml |  6 ------
 src/respond.ml |  9 ++++++++
 src/static.ml  | 56 ++++++++++++++++++++++++++++----------------------
 3 files changed, 40 insertions(+), 31 deletions(-)

diff --git a/src/headers.ml b/src/headers.ml
index fd6ebfc7..e3fccd79 100644
--- a/src/headers.ml
+++ b/src/headers.ml
@@ -12,9 +12,6 @@ let select_mimetype headers =
   Cohttp.Accept.media_ranges opt
   |> Cohttp.Accept.qsort
   |> List.find_map (fun (_q, (m, _p)) -> Assets.Mimetype.of_cohttp m)
-  |> function
-  | None -> Assets.Mimetype.default
-  | Some mime -> mime
 
 let select_language headers =
   let opt = Vif.Headers.get headers "accept-language" in
@@ -22,9 +19,6 @@ let select_language headers =
   |> Cohttp.Accept.qsort
   |> List.map snd
   |> List.find_map Assets.Language.of_cohttp
-  |> function
-  | None -> Assets.Language.default
-  | Some lang -> lang
 
 let select_encoding headers =
   let opt = Vif.Headers.get headers "accept-encoding" in
diff --git a/src/respond.ml b/src/respond.ml
index ea17f7f7..a5388635 100644
--- a/src/respond.ml
+++ b/src/respond.ml
@@ -24,6 +24,15 @@ let bad_request ?hint req =
   let body = mk_error_content ?hint `Bad_request in
   respond_json req body `Bad_request
 
+let unsupported_media_type req =
+  Logs.err (fun m -> m "unsupported media type");
+  let open Vif.Response in
+  let open Syntax in
+  let* () = add ~field:"accept" Headers.accept_header_value in
+  let* () = add ~field:"avail-languages" Headers.avail_languages_header_value in
+  let body = mk_error_content `Unsupported_media_type in
+  respond_json req body `Unsupported_media_type
+
 let ok content req =
   Logs.debug (fun m -> m "ok");
   respond_json req content `OK
diff --git a/src/static.ml b/src/static.ml
index 6d556931..23367426 100644
--- a/src/static.ml
+++ b/src/static.ml
@@ -13,31 +13,37 @@ let aux asset req _server _env =
   match has_matching_etag with
   | Error e -> Respond.bad_request ~hint:e req
   | Ok true -> Respond.not_modified ()
-  | Ok false ->
-      let mime = Headers.select_mimetype headers in
-      let lang = Headers.select_language headers in
-      let compression = Headers.select_encoding headers in
-      let data = Assets.get_content ~mime ~lang asset in
-      (* -- *)
-      let open Vif.Response in
-      let open Syntax in
-      let* () = with_string ?compression req data in
-      let* () =
-        let etag_field_value = Headers_lib.Etag.to_field_string etag in
-        add ~field:"etag" etag_field_value
-      in
-      let* () =
-        (* todo: is it "taler-privacy-version" for /policy ? *)
-        add ~field:"taler-terms-version" (Assets.legal_version asset)
-      in
-      let* () =
-        add ~field:"avail-languages" Headers.avail_languages_header_value
-      in
-      let* () =
-        let content_type = Fmt.str "%a" Assets.Mimetype.pp mime in
-        add ~field:"content-type" content_type
-      in
-      respond `OK
+  | Ok false -> (
+      match Headers.select_mimetype headers with
+      | None -> Respond.unsupported_media_type req
+      | Some mime ->
+          let lang =
+            Headers.select_language headers
+            |> Option.value ~default:Assets.Language.default
+          in
+          let compression = Headers.select_encoding headers in
+          let data = Assets.get_content ~mime ~lang asset in
+          (* -- *)
+          let open Vif.Response in
+          let open Syntax in
+          let* () = with_string ?compression req data in
+          let* () =
+            let etag_field_value = Headers_lib.Etag.to_field_string etag in
+            add ~field:"etag" etag_field_value
+          in
+          let* () = add ~field:"accept" Headers.accept_header_value in
+          let* () =
+            add ~field:"avail-languages" Headers.avail_languages_header_value
+          in
+          let* () =
+            (* todo: is it "taler-privacy-version" for /policy ? *)
+            add ~field:"taler-terms-version" (Assets.legal_version asset)
+          in
+          let* () =
+            let content_type = Fmt.str "%a" Assets.Mimetype.pp mime in
+            add ~field:"content-type" content_type
+          in
+          respond `OK)
 
 let terms req _server _env =
   Logs.info (fun m -> m "GET /terms");