82 lines
2.0 KiB
Go
82 lines
2.0 KiB
Go
package backend
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import (
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"fmt"
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"image"
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"image/jpeg"
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"log"
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"os"
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"path"
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"path/filepath"
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"github.com/20after4/configdir"
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"github.com/bluele/gcache"
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)
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type ImageManager struct {
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s *ServerManager
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baseCacheDir string
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thumbnailCache gcache.Cache
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}
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func NewImageManager(s *ServerManager, baseCacheDir string) *ImageManager {
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cache := gcache.New(100).LRU().Build()
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if err := configdir.MakePath(baseCacheDir); err != nil {
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log.Println("failed to create album cover cache dir")
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baseCacheDir = ""
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}
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return &ImageManager{
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s: s,
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baseCacheDir: baseCacheDir,
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thumbnailCache: cache,
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}
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}
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func (i *ImageManager) GetAlbumThumbnail(albumID string) (image.Image, error) {
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// in-memory cache
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if i.thumbnailCache.Has(albumID) {
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if img, err := i.thumbnailCache.Get(albumID); err == nil {
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return img.(image.Image), nil
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}
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}
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// on disc cache
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path := filepath.Join(i.ensureCoverCacheDir(), fmt.Sprintf("%s.jpg", albumID))
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if i.ensureCoverCacheDir() != "" {
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if _, err := os.Stat(path); err == nil {
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// serve image from on-disc cache
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// TODO: image may have changed on server.
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// first, return cached image, then fetch fresh img from server in background
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if f, err := os.Open(path); err == nil {
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defer f.Close()
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if img, _, err := image.Decode(f); err == nil {
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i.thumbnailCache.Set(albumID, img)
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return img, nil
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}
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}
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}
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}
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// fetch from server
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img, err := i.s.Server.GetCoverArt(albumID, map[string]string{"size": "300"})
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if err != nil {
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return nil, err
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}
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if i.ensureCoverCacheDir() != "" {
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if f, err := os.Create(path); err == nil {
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defer f.Close()
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if err := jpeg.Encode(f, img, nil /*options*/); err != nil {
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log.Printf("failed to cache image: %s", err.Error())
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}
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}
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}
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i.thumbnailCache.Set(albumID, img)
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return img, nil
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}
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func (i *ImageManager) ensureCoverCacheDir() string {
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path := path.Join(i.baseCacheDir, i.s.ServerID.String(), "covers")
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configdir.MakePath(path)
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return path
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}
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