Allow header

src/wisp.gleam

@@ -342,18 +342,21 @@ pub fn entity_too_large() -> Response {
   HttpResponse(413, [], Empty)
 }
 
-// TODO: test
 /// Create an empty response with status code 415: Unsupported media type.
 ///
+/// The `allow` header will be set to a comma separated list of the permitted
+/// content-types.
+///
 /// # Examples
 ///
 /// ```gleam
-/// unsupported_media_type()
-/// // -> Response(415, [], Empty)
+/// unsupported_media_type(accept: ["application/json", "text/plain"])
+/// // -> Response(415, [#("allow", "application/json, text/plain")], Empty)
 /// ```
 ///
-pub fn unsupported_media_type() -> Response {
-  HttpResponse(415, [], Empty)
+pub fn unsupported_media_type(accept acceptable: List(String)) -> Response {
+  let acceptable = string.join(acceptable, ", ")
+  HttpResponse(415, [#("accept", acceptable)], Empty)
 }
 
 /// Create an empty response with status code 500: Internal server error.
@@ -691,7 +694,10 @@ pub fn require_form(
 
     Ok("multipart/form-data") -> bad_request()
 
-    _ -> unsupported_media_type()
+    _ ->
+      unsupported_media_type([
+        "application/x-www-form-urlencoded", "multipart/form-data",
+      ])
   }
 }
 

test/wisp_test.gleam

@@ -84,6 +84,15 @@ pub fn method_not_allowed_test() {
   |> should.equal(Response(405, [#("allow", "DELETE, GET, PATCH")], wisp.Empty))
 }
 
+pub fn unsupported_media_type_test() {
+  wisp.unsupported_media_type(accept: ["application/json", "text/plain"])
+  |> should.equal(Response(
+    415,
+    [#("accept", "application/json, text/plain")],
+    wisp.Empty,
+  ))
+}
+
 pub fn html_response_test() {
   let body = string_builder.from_string("Hello, world!")
   let response = wisp.html_response(body, 200)
@@ -495,7 +504,11 @@ pub fn form_unknown_content_type_test() {
   |> wisp.test_request
   |> request.set_header("content-type", "text/form")
   |> form_handler(fn(_) { panic as "should be unreachable" })
-  |> should.equal(Response(415, [], wisp.Empty))
+  |> should.equal(Response(
+    415,
+    [#("accept", "application/x-www-form-urlencoded, multipart/form-data")],
+    wisp.Empty,
+  ))
 }
 
 pub fn multipart_form_with_files_test() {