Search Deezer and MusicBrainz together; add preview clips

Search - Albums and songs search Deezer and MusicBrainz at once and merge the results: duplicates keep the Deezer copy, best word matches first. Deezer's search misses albums it carries (Death Magnetic) and most game soundtracks; MusicBrainz finds them - MusicBrainz secondary types are shown ("Soundtrack", "Live") - Settings: Deezer + MusicBrainz (default), Deezer only, MusicBrainz only - Search results show which service they came from Previews - Songs and albums get a play button (cards, rows, detail view, editor, and Deezer search results) for a 30-second Deezer clip; albums play their most popular track - Clips are looked up fresh (Deezer URLs expire), cached 10 minutes, and streamed through Canon with Range support; hidden lists stay private - Entries from MusicBrainz or added by hand are matched to Deezer on save so they can preview too - "Play previews" toggle in Settings → Profile Tests cover merging and title/artist matching; `-tags live` runs checks against the real services. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-09-25 10:10:15 -07:00
1 parent 6d92b46130
commit b09533cc00
@@ -0,0 +1,194 @@
+package server
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"regexp"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/cdnutter/canon/internal/providers"
+	"github.com/cdnutter/canon/internal/store"
+)
+
+// Previews are 30-second clips from Deezer, streamed through Canon so
+// visitors never connect to Deezer directly. Deezer's clip URLs expire, so
+// they're looked up on demand and cached briefly.
+
+var deezerRefRe = regexp.MustCompile(`^(track|album):[0-9]+$`)
+
+// deezerRef is the Deezer track/album an item can preview, or "".
+func deezerRef(it store.Item) string {
+	ref := it.Extra["deezer"]
+	if it.Provider == "deezer" {
+		ref = it.ProviderID
+	}
+	if !deezerRefRe.MatchString(ref) {
+		return ""
+	}
+	return ref
+}
+
+func hasPreviews(category string) bool { return category == "song" || category == "album" }
+
+type previewCache struct {
+	mu sync.Mutex
+	m  map[string]cachedPreview
+}
+
+type cachedPreview struct {
+	url     string
+	expires time.Time
+}
+
+func (c *previewCache) get(ref string) (string, bool) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	p, ok := c.m[ref]
+	if !ok || time.Now().After(p.expires) {
+		return "", false
+	}
+	return p.url, true
+}
+
+func (c *previewCache) put(ref, url string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.m == nil || len(c.m) > 2000 {
+		c.m = map[string]cachedPreview{}
+	}
+	c.m[ref] = cachedPreview{url: url, expires: time.Now().Add(10 * time.Minute)}
+}
+
+func (c *previewCache) drop(ref string) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	delete(c.m, ref)
+}
+
+// handleItemPreview plays the preview for a list item. It follows the
+// list's visibility, like the list page does.
+func (s *Server) handleItemPreview(w http.ResponseWriter, r *http.Request) {
+	id, err := strconv.ParseInt(r.PathValue("id"), 10, 64)
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+	it, err := s.store.ItemByID(r.Context(), id)
+	if err != nil {
+		http.NotFound(w, r)
+		return
+	}
+	l, err := s.store.ListByID(r.Context(), it.ListID)
+	if err != nil || !hasPreviews(l.Category) || !s.site(r.Context()).ShowPreviews {
+		http.NotFound(w, r)
+		return
+	}
+	if !l.Visible {
+		if _, ok := s.currentUser(r); !ok {
+			http.NotFound(w, r)
+			return
+		}
+	}
+	ref := deezerRef(it)
+	if ref == "" {
+		http.NotFound(w, r)
+		return
+	}
+	s.streamPreview(w, r, ref)
+}
+
+// handleAdminPreview plays a search result before it's added. It's a plain
+// GET behind the session (an <audio> element can't send the API header).
+func (s *Server) handleAdminPreview(w http.ResponseWriter, r *http.Request) {
+	ref := r.URL.Query().Get("ref")
+	if !deezerRefRe.MatchString(ref) {
+		http.NotFound(w, r)
+		return
+	}
+	s.streamPreview(w, r, ref)
+}
+
+func (s *Server) streamPreview(w http.ResponseWriter, r *http.Request, ref string) {
+	for attempt := 0; attempt < 2; attempt++ {
+		url, cached := s.previews.get(ref)
+		if !cached {
+			ctx, cancel := context.WithTimeout(r.Context(), 10*time.Second)
+			var err error
+			url, err = s.providers.DeezerPreview(ctx, ref)
+			cancel()
+			if errors.Is(err, providers.ErrNoPreview) {
+				http.Error(w, "No preview available", http.StatusNotFound)
+				return
+			}
+			if err != nil {
+				s.log.Warn("preview lookup failed", "ref", ref, "err", err)
+				http.Error(w, "Preview unavailable", http.StatusBadGateway)
+				return
+			}
+			s.previews.put(ref, url)
+		}
+		req, err := http.NewRequestWithContext(r.Context(), http.MethodGet, url, nil)
+		if err != nil {
+			break
+		}
+		req.Header.Set("User-Agent", providers.UserAgent)
+		// Forward ranges so browsers (Safari especially) can stream and seek.
+		if rg := r.Header.Get("Range"); rg != "" {
+			req.Header.Set("Range", rg)
+		}
+		resp, err := s.previewClient.Do(req)
+		if err != nil {
+			s.log.Warn("preview fetch failed", "ref", ref, "err", err)
+			http.Error(w, "Preview unavailable", http.StatusBadGateway)
+			return
+		}
+		if resp.StatusCode != http.StatusOK && resp.StatusCode != http.StatusPartialContent {
+			resp.Body.Close()
+			// Probably an expired clip URL; look it up again once.
+			s.previews.drop(ref)
+			continue
+		}
+		defer resp.Body.Close()
+		h := w.Header()
+		for _, k := range []string{"Content-Type", "Content-Length", "Content-Range", "Accept-Ranges"} {
+			if v := resp.Header.Get(k); v != "" {
+				h.Set(k, v)
+			}
+		}
+		if h.Get("Content-Type") == "" {
+			h.Set("Content-Type", "audio/mpeg")
+		}
+		h.Set("Cache-Control", "private, max-age=600")
+		w.WriteHeader(resp.StatusCode)
+		io.Copy(w, resp.Body)
+		return
+	}
+	http.Error(w, "Preview unavailable", http.StatusBadGateway)
+}
+
+// matchDeezer links a song or album that didn't come from Deezer to its
+// Deezer counterpart so it can play a preview. Failures just mean no preview.
+func (s *Server) matchDeezer(ctx context.Context, category string, it *store.Item) {
+	if !hasPreviews(category) || it.Provider == "deezer" {
+		return
+	}
+	if it.Extra == nil {
+		it.Extra = map[string]string{}
+	}
+	mctx, cancel := context.WithTimeout(ctx, 8*time.Second)
+	defer cancel()
+	ref, err := s.providers.MatchDeezer(mctx, category, it.Title, it.Subtitle)
+	if err != nil {
+		s.log.Warn("matching Deezer preview", "title", it.Title, "err", err)
+		return
+	}
+	if ref == "" {
+		delete(it.Extra, "deezer")
+		return
+	}
+	it.Extra["deezer"] = ref
+}