feat(jellyfin): item image endpoint via artwork service

server/jellyfin/api.go

@@ -50,6 +50,11 @@ func (api *Router) routes() http.Handler {
 	r.Post("/Users/AuthenticateByName", api.authenticateByName)
 	r.Get("/Users/Public", api.getPublicUsers)
 
+	// Images are intentionally public and not library-scoped: artwork isn't sensitive media
+	// content, and clients (e.g. Finamp) load it via <img> tags with only ?api_key= in the URL.
+	r.Get("/Items/{itemId}/Images/{type}", api.getItemImage)
+	r.Get("/Items/{itemId}/Images/{type}/{index}", api.getItemImage)
+
 	r.Group(func(r chi.Router) {
 		r.Use(api.authenticate)
 		r.Get("/UserViews", api.getUserViews)

server/jellyfin/images.go

@@ -0,0 +1,42 @@
+package jellyfin
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"strconv"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/navidrome/navidrome/model"
+)
+
+func (api *Router) getItemImage(w http.ResponseWriter, r *http.Request) {
+	ctx := r.Context()
+	itemId := chi.URLParam(r, "itemId")
+	size, _ := strconv.Atoi(r.URL.Query().Get("maxWidth"))
+
+	artID := api.resolveArtworkID(ctx, itemId)
+	reader, _, err := api.artwork.GetOrPlaceholder(ctx, artID, size, false)
+	if err != nil {
+		http.Error(w, "Not Found", http.StatusNotFound)
+		return
+	}
+	defer reader.Close()
+	w.Header().Set("Content-Type", "image/jpeg")
+	_, _ = io.Copy(w, reader)
+}
+
+// resolveArtworkID maps a bare Jellyfin item id to a Navidrome ArtworkID string
+// by probing album -> artist -> media file (music items only).
+func (api *Router) resolveArtworkID(ctx context.Context, itemId string) string {
+	if al, err := api.ds.Album(ctx).Get(itemId); err == nil {
+		return al.CoverArtID().String()
+	}
+	if ar, err := api.ds.Artist(ctx).Get(itemId); err == nil {
+		return ar.CoverArtID().String()
+	}
+	if mf, err := api.ds.MediaFile(ctx).Get(itemId); err == nil {
+		return mf.CoverArtID().String()
+	}
+	return (model.ArtworkID{}).String()
+}

server/jellyfin/images_test.go

@@ -0,0 +1,48 @@
+package jellyfin
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"time"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/navidrome/navidrome/core/artwork"
+	"github.com/navidrome/navidrome/model"
+	"github.com/navidrome/navidrome/tests"
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+type fakeArtwork struct {
+	artwork.Artwork
+	recvId string
+}
+
+func (f *fakeArtwork) GetOrPlaceholder(ctx context.Context, id string, size int, square bool) (io.ReadCloser, time.Time, error) {
+	f.recvId = id
+	return io.NopCloser(strings.NewReader("IMG")), time.Now(), nil
+}
+
+var _ = Describe("Images", func() {
+	It("streams album artwork", func() {
+		ds := &tests.MockDataStore{}
+		ds.Album(context.Background()).(*tests.MockAlbumRepo).SetData(model.Albums{{ID: "a1", Name: "One"}})
+		fa := &fakeArtwork{}
+		api := &Router{ds: ds, artwork: fa}
+
+		w := httptest.NewRecorder()
+		r := httptest.NewRequest("GET", "/Items/a1/Images/Primary", nil)
+		rctx := chi.NewRouteContext()
+		rctx.URLParams.Add("itemId", "a1")
+		rctx.URLParams.Add("type", "Primary")
+		r = r.WithContext(context.WithValue(r.Context(), chi.RouteCtxKey, rctx))
+		api.getItemImage(w, r)
+
+		Expect(w.Code).To(Equal(http.StatusOK))
+		Expect(w.Body.String()).To(Equal("IMG"))
+		Expect(fa.recvId).To(ContainSubstring("a1"))
+	})
+})