feat: artist image disk cache + fix top results artist photos

Two changes:

1. Artist image disk cache: ArtistImageProvider now fetches the
   actual image bytes from Wikimedia Commons and caches them on
   disk (~/.local/share/yellowjacket/artist-image-cache/{mbid}.jpg).
   Returns base64 data URLs, same pattern as CoverArtProxy.
   First lookup: resolve URL via MB/Wikidata + fetch image (~2s).
   Subsequent: instant from disk cache.
   404s cached as empty files to avoid re-fetching.

2. Top results artist photos: the Top Results section now shows
   artist images from the artistImageCache, same as the Artists
   section. Also shows englishName in the top card display name.
This commit is contained in:
2026-03-25 22:28:52 -04:00
parent 9b88b88523
commit 963269b753
3 changed files with 169 additions and 56 deletions
+156 -48
View File
@@ -3,80 +3,128 @@ package explore
import (
"context"
"crypto/md5" //nolint:gosec // MD5 used for Wikimedia URL hashing, not security
"encoding/base64"
"encoding/json"
"errors"
"fmt"
"io"
"log/slog"
"net/http"
"os"
"path/filepath"
"strings"
"sync"
"time"
"yellowjacket/backend/database"
"yellowjacket/backend/system"
)
// ErrArtistImage is returned when an artist image HTTP fetch fails.
var ErrArtistImage = errors.New("artist image fetch failed")
const (
// wikimediaThumbBase is the base URL for Wikimedia Commons
// thumbnail generation.
wikimediaThumbBase = "https://upload.wikimedia.org/wikipedia/commons/thumb"
// wikidataAPIBase is the base URL for the Wikidata API.
wikidataAPIBase = "https://www.wikidata.org/w/api.php"
// artistImageSize is the default thumbnail width in pixels.
artistImageSize = 250
// artistImageTimeout is the HTTP timeout for image URL lookups.
artistImageTimeout = 10 * time.Second
// artistImageCacheTTL is how long resolved image URLs are cached.
wikimediaThumbBase = "https://upload.wikimedia.org/wikipedia/commons/thumb"
wikidataAPIBase = "https://www.wikidata.org/w/api.php"
artistImageSize = 250
artistImageTimeout = 10 * time.Second
artistImageCacheTTL = 30 * 24 * time.Hour
artistImageDir = "artist-image-cache"
artistImageMaxBytes = 2 * 1024 * 1024 // 2 MB max per image
)
// ArtistImageProvider resolves artist MBIDs to image URLs. It
// fetches the artist's MB url-rels (once, cached 30 days), extracts
// image sources from them, and returns a Wikimedia Commons thumbnail
// URL. Designed to be extended with additional sources (fanart.tv,
// etc.) by adding to the resolve chain.
// ArtistImageProvider resolves artist MBIDs to images. It checks
// three sources in order:
// 1. Local disk cache (instant, from previous fetch)
// 2. MB url-rels → Wikimedia Commons thumb URL → fetch + cache
// 3. Wikidata P18 → Wikimedia Commons thumb URL → fetch + cache
//
// Returns base64 data URLs for display in <img src="data:...">.
type ArtistImageProvider struct {
db *database.DB
cache *Cache
mbLimiter *RateLimiter
client *http.Client
logger *slog.Logger
imageDir string
mu sync.Mutex // serializes disk writes
}
// NewArtistImageProvider creates a provider that resolves artist
// images via MusicBrainz relationships and Wikidata.
// NewArtistImageProvider creates a provider that resolves and caches
// artist images.
func NewArtistImageProvider(
db *database.DB,
cache *Cache,
mbLimiter *RateLimiter,
logger *slog.Logger,
) *ArtistImageProvider {
dir := ""
dataDir, err := system.GetUserDataDirPath()
if err == nil {
dir = filepath.Join(dataDir, artistImageDir)
_ = os.MkdirAll(dir, 0o755)
}
return &ArtistImageProvider{
db: db,
cache: cache,
mbLimiter: mbLimiter,
client: &http.Client{Timeout: artistImageTimeout},
logger: logger,
imageDir: dir,
}
}
// GetArtistImageURL returns a Wikimedia Commons thumbnail URL for
// the given artist MBID, or "" if no image is available. Results
// are cached for 30 days.
func (p *ArtistImageProvider) GetArtistImageURL(artistMBID string) string {
if artistMBID == "" {
// GetArtistImage returns a base64 data URL for the artist's photo.
// Checks disk cache first, then resolves via MB/Wikidata and fetches
// the image from Wikimedia Commons. Returns "" if no image.
func (p *ArtistImageProvider) GetArtistImage(artistMBID string) string {
if artistMBID == "" || p.imageDir == "" {
return ""
}
// Check resolved URL cache first.
cacheKey := "artist-image:" + artistMBID
// Source 1: disk cache (instant).
if dataURL := p.readDiskCache(artistMBID); dataURL != "" {
return dataURL
}
// Check if we already know there's no image (cached miss marker).
if p.isDiskCacheMiss(artistMBID) {
return ""
}
// Source 2+3: resolve URL then fetch image.
imageURL := p.resolveURL(artistMBID)
if imageURL == "" {
p.writeDiskCache(artistMBID, nil) // miss marker
return ""
}
// Fetch the actual image bytes.
data, err := p.fetchImageBytes(imageURL)
if err != nil || len(data) == 0 {
p.writeDiskCache(artistMBID, nil)
return ""
}
p.writeDiskCache(artistMBID, data)
return toDataURL(data, artistMBID)
}
// resolveURL finds the Wikimedia Commons thumbnail URL for an
// artist via MB url-rels and Wikidata. The URL itself (not image
// bytes) is cached in explore_cache for 30 days.
func (p *ArtistImageProvider) resolveURL(artistMBID string) string {
cacheKey := "artist-image-url:" + artistMBID
if data, ok := p.cache.Get(cacheKey); ok {
return string(data)
}
// Fetch MB url-rels (cached separately, shared with other uses).
rels := p.fetchMBRels(artistMBID)
if rels == nil {
p.cache.Set(cacheKey, []byte(""), artistImageCacheTTL, artistMBID, "artist")
@@ -84,28 +132,19 @@ func (p *ArtistImageProvider) GetArtistImageURL(artistMBID string) string {
return ""
}
// Try each source in priority order.
imageURL := p.fromDirectImageRel(rels)
if imageURL == "" {
imageURL = p.fromWikidataRel(rels)
}
// Cache the result (even "" = no image).
p.cache.Set(cacheKey, []byte(imageURL), artistImageCacheTTL, artistMBID, "artist")
if imageURL != "" {
p.logger.Debug("artist image resolved",
"mbid", artistMBID,
"url", imageURL,
)
}
return imageURL
}
// ---------------------------------------------------------------------------
// MB url-rels fetching (shared by all sources)
// MB url-rels
// ---------------------------------------------------------------------------
type mbRelation struct {
@@ -133,7 +172,6 @@ func (p *ArtistImageProvider) fetchMBRels(artistMBID string) []mbRelation {
artistMBID,
)
// Rate-limit the MB API call.
if err := p.mbLimiter.Wait(context.Background()); err != nil {
return nil
}
@@ -162,7 +200,7 @@ func (p *ArtistImageProvider) fetchMBRels(artistMBID string) []mbRelation {
}
// ---------------------------------------------------------------------------
// Source 1: direct image relation (Commons wiki page link)
// Source 1: direct image relation
// ---------------------------------------------------------------------------
func (p *ArtistImageProvider) fromDirectImageRel(rels []mbRelation) string {
@@ -173,7 +211,6 @@ func (p *ArtistImageProvider) fromDirectImageRel(rels []mbRelation) string {
resource := rel.URL.Resource
// "https://commons.wikimedia.org/wiki/File:Name.jpg"
if idx := strings.LastIndex(resource, "File:"); idx >= 0 {
filename := resource[idx+5:]
@@ -185,11 +222,10 @@ func (p *ArtistImageProvider) fromDirectImageRel(rels []mbRelation) string {
}
// ---------------------------------------------------------------------------
// Source 2: Wikidata P18 property
// Source 2: Wikidata P18
// ---------------------------------------------------------------------------
func (p *ArtistImageProvider) fromWikidataRel(rels []mbRelation) string {
// Find the wikidata Q-ID.
qid := ""
for _, rel := range rels {
@@ -205,14 +241,12 @@ func (p *ArtistImageProvider) fromWikidataRel(rels []mbRelation) string {
return ""
}
// Check cache for this Wikidata entity.
cacheKey := "wikidata-p18:" + qid
if data, ok := p.cache.Get(cacheKey); ok {
return string(data)
}
// Fetch P18 from Wikidata.
url := fmt.Sprintf(
"%s?action=wbgetclaims&entity=%s&property=P18&format=json",
wikidataAPIBase, qid,
@@ -247,12 +281,77 @@ func (p *ArtistImageProvider) fromWikidataRel(rels []mbRelation) string {
return thumbURL
}
// ---------------------------------------------------------------------------
// Disk cache
// ---------------------------------------------------------------------------
func (p *ArtistImageProvider) diskCachePath(mbid string) string {
return filepath.Join(p.imageDir, mbid+".jpg")
}
func (p *ArtistImageProvider) readDiskCache(mbid string) string {
data, err := os.ReadFile(p.diskCachePath(mbid))
if err != nil {
return ""
}
if len(data) == 0 {
return "" // miss marker
}
return toDataURL(data, mbid)
}
func (p *ArtistImageProvider) isDiskCacheMiss(mbid string) bool {
info, err := os.Stat(p.diskCachePath(mbid))
return err == nil && info.Size() == 0
}
func (p *ArtistImageProvider) writeDiskCache(mbid string, data []byte) {
p.mu.Lock()
defer p.mu.Unlock()
if data == nil {
data = []byte{} // miss marker
}
_ = os.WriteFile(p.diskCachePath(mbid), data, 0o644)
}
// ---------------------------------------------------------------------------
// Image fetching
// ---------------------------------------------------------------------------
func (p *ArtistImageProvider) fetchImageBytes(imageURL string) ([]byte, error) {
ctx, cancel := context.WithTimeout(context.Background(), artistImageTimeout)
defer cancel()
req, err := http.NewRequestWithContext(ctx, http.MethodGet, imageURL, nil)
if err != nil {
return nil, err
}
req.Header.Set("User-Agent", lbUserAgent)
resp, err := p.client.Do(req)
if err != nil {
return nil, err
}
defer func() { _ = resp.Body.Close() }()
if resp.StatusCode != http.StatusOK {
return nil, fmt.Errorf("%w: HTTP %d", ErrArtistImage, resp.StatusCode)
}
return io.ReadAll(io.LimitReader(resp.Body, artistImageMaxBytes))
}
// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------
// wikimediaThumbURL constructs a Wikimedia Commons thumbnail URL
// from a filename using the MD5 directory bucketing scheme.
func wikimediaThumbURL(filename string) string {
if filename == "" {
return ""
@@ -293,3 +392,12 @@ func (p *ArtistImageProvider) fetchURL(url string) ([]byte, error) {
return io.ReadAll(resp.Body)
}
func toDataURL(data []byte, _ string) string {
mime := "image/jpeg"
if len(data) > 1 && data[0] == 0x89 && data[1] == 0x50 {
mime = "image/png"
}
return "data:" + mime + ";base64," + base64.StdEncoding.EncodeToString(data)
}
+8 -6
View File
@@ -38,7 +38,9 @@ func NewExploreService(logger *slog.Logger, db *database.DB) *Service {
lb := NewListenBrainzClient(limiter, cache, logger.WithGroup("listenbrainz"))
index := NewSearchIndex(db, lb, logger.WithGroup("search-index"))
artProxy := NewCoverArtProxy(db, limiter)
artistImg := NewArtistImageProvider(cache, NewRateLimiter(), logger.WithGroup("artist-image"))
artistImg := NewArtistImageProvider(
db, cache, NewRateLimiter(), logger.WithGroup("artist-image"),
)
logger.Info("explore service created")
@@ -188,12 +190,12 @@ func (e *Service) GetThumbnails(requests []ThumbnailRequest) map[string]string {
return result
}
// GetArtistImageURL returns a Wikimedia Commons thumbnail URL for
// the given artist MBID. Resolved via MB url-rels → Wikidata P18
// → Commons thumb URL. Cached for 30 days. Returns "" if no
// image is available.
// GetArtistImageURL returns a base64 data URL for the artist's
// photo. Cached on disk — first call resolves via MB/Wikidata and
// fetches from Wikimedia Commons, subsequent calls are instant.
// Returns "" if no image is available.
func (e *Service) GetArtistImageURL(artistMBID string) string {
return e.artistImg.GetArtistImageURL(artistMBID)
return e.artistImg.GetArtistImage(artistMBID)
}
// Search concurrently queries MusicBrainz for artists, release
@@ -866,6 +866,7 @@ export class ExploreView extends LitElement {
if (item.type === 'artist' && item.artist) {
const a = item.artist;
const hue = nameToHue(a.name);
const imgURL = this.artistImageCache.get(a.mbid);
return html`
<div
class="top-card"
@@ -883,10 +884,12 @@ export class ExploreView extends LitElement {
class="artist-avatar"
style="background: hsl(${hue}, 45%, 35%)"
>
${(a.englishName || a.name).charAt(0).toUpperCase()}
${imgURL
? html`<img src="${imgURL}" alt="${a.englishName || a.name}" />`
: (a.englishName || a.name).charAt(0).toUpperCase()}
</div>
<div class="top-card-info">
<div class="top-card-name">${a.name}</div>
<div class="top-card-name">${a.englishName || a.name}</div>
<div class="top-card-meta">Artist${a.country ? ` · ${a.country}` : ''}</div>
</div>
</div>