fix(jellyfin): resolve playlist ids in getItem

server/jellyfin/items.go

@@ -234,9 +234,9 @@ func (api *Router) listPlaylists(ctx context.Context, opts model.QueryOptions, f
 	return result(slice.Map(playlists, dto.PlaylistToBaseItem), int(total), opts.Offset), nil
 }
 
-// getItem fetches a single entity by id, trying library view, album, artist and song in turn.
-// For albums and songs (which each belong to exactly one library) it 404s if the current user
-// lacks access to that library, so an id can't be used to probe content outside the user's
+// getItem fetches a single entity by id, trying library view, album, artist, song and playlist in
+// turn. For albums and songs (which each belong to exactly one library) it 404s if the current
+// user lacks access to that library, so an id can't be used to probe content outside the user's
 // libraries.
 func (api *Router) getItem(w http.ResponseWriter, r *http.Request) {
 	ctx := r.Context()
@@ -281,6 +281,12 @@ func (api *Router) getItem(w http.ResponseWriter, r *http.Request) {
 		api.ok(w, r, dto.SongToBaseItem(*mf))
 		return
 	}
+	// api.playlists.Get enforces ownership/visibility itself, so a non-owned or missing playlist
+	// id falls through to the generic 404 below, same as every other probe here.
+	if pl, err := api.playlists.Get(ctx, id); err == nil {
+		api.ok(w, r, dto.PlaylistToBaseItem(*pl))
+		return
+	}
 	http.Error(w, "Not Found", http.StatusNotFound)
 }
 

server/jellyfin/items_test.go

@@ -26,6 +26,7 @@ func withChiURLParam(r *http.Request, key, value string) *http.Request {
 var _ = Describe("Items", func() {
 	var api *Router
 	var ds *tests.MockDataStore
+	var fp *fakePlaylists
 	// alice has access to library 1 only; used by tests that don't care about scoping.
 	ctxUser := func() context.Context {
 		return request.WithUser(context.Background(), model.User{ID: "u1", UserName: "alice", Libraries: model.Libraries{{ID: 1, Name: "Music"}}})
@@ -39,7 +40,8 @@ var _ = Describe("Items", func() {
 	}
 	BeforeEach(func() {
 		ds = &tests.MockDataStore{}
-		api = &Router{ds: ds}
+		fp = &fakePlaylists{}
+		api = &Router{ds: ds, playlists: fp}
 	})
 
 	Describe("getItems", func() {
@@ -428,6 +430,31 @@ var _ = Describe("Items", func() {
 			Expect(w.Code).To(Equal(http.StatusNotFound))
 		})
 
+		// Finamp's SyncBuffer fetches a playlist by id as a plain item; without this probe it
+		// 404s with "Could not fetch BaseItemDto <playlist> from server."
+		It("resolves a playlist id via the playlists service", func() {
+			fp.getByIDPls = &model.Playlist{ID: "p1", Name: "My Mix", SongCount: 5}
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest("GET", "/Items/p1", nil).WithContext(ctxUser())
+			r = withChiURLParam(r, "itemId", "p1")
+			api.getItem(w, r)
+			Expect(w.Code).To(Equal(http.StatusOK))
+			var item dto.BaseItemDto
+			Expect(json.Unmarshal(w.Body.Bytes(), &item)).To(Succeed())
+			Expect(item.Id).To(Equal("p1"))
+			Expect(item.Name).To(Equal("My Mix"))
+			Expect(item.Type).To(Equal("Playlist"))
+		})
+
+		It("returns 404 for a non-owned or absent playlist id", func() {
+			fp.getByIDErr = model.ErrNotFound
+			w := httptest.NewRecorder()
+			r := httptest.NewRequest("GET", "/Items/p1", nil).WithContext(ctxUser())
+			r = withChiURLParam(r, "itemId", "p1")
+			api.getItem(w, r)
+			Expect(w.Code).To(Equal(http.StatusNotFound))
+		})
+
 		It("resolves a library-view id for an admin even though their Libraries slice is empty", func() {
 			ds.Library(context.Background()).(*tests.MockLibraryRepo).SetData(model.Libraries{{ID: 1, Name: "Music Library"}})
 			w := httptest.NewRecorder()

server/jellyfin/playlists_test.go

@@ -27,6 +27,9 @@ type fakePlaylists struct {
 	getPls *model.Playlist
 	getErr error
 
+	getByIDPls *model.Playlist
+	getByIDErr error
+
 	addPlaylistID string
 	addIds        []string
 	addErr        error
@@ -45,6 +48,19 @@ func (f *fakePlaylists) Create(_ context.Context, _ string, name string, ids []s
 	return "pl-new", nil
 }
 
+// Get defaults to model.ErrNotFound when getByIDPls/getByIDErr aren't set, matching the real
+// service's behavior for a missing or inaccessible playlist and letting getItem tests that don't
+// care about playlists leave it unconfigured.
+func (f *fakePlaylists) Get(_ context.Context, _ string) (*model.Playlist, error) {
+	if f.getByIDErr != nil {
+		return nil, f.getByIDErr
+	}
+	if f.getByIDPls == nil {
+		return nil, model.ErrNotFound
+	}
+	return f.getByIDPls, nil
+}
+
 func (f *fakePlaylists) GetWithTracks(_ context.Context, _ string) (*model.Playlist, error) {
 	if f.getErr != nil {
 		return nil, f.getErr