Started the big refactor to extract common logic from engine package (Subsonic only) to core package (more generic)

core/auth/auth.go

@@ -0,0 +1,76 @@
+package auth
+
+import (
+	"context"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/deluan/navidrome/conf"
+	"github.com/deluan/navidrome/consts"
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/model"
+	"github.com/dgrijalva/jwt-go"
+	"github.com/go-chi/jwtauth"
+)
+
+var (
+	once           sync.Once
+	JwtSecret      []byte
+	TokenAuth      *jwtauth.JWTAuth
+	sessionTimeOut time.Duration
+)
+
+func InitTokenAuth(ds model.DataStore) {
+	once.Do(func() {
+		secret, err := ds.Property(context.TODO()).DefaultGet(consts.JWTSecretKey, "not so secret")
+		if err != nil {
+			log.Error("No JWT secret found in DB. Setting a temp one, but please report this error", err)
+		}
+		JwtSecret = []byte(secret)
+		TokenAuth = jwtauth.New("HS256", JwtSecret, nil)
+	})
+}
+
+func CreateToken(u *model.User) (string, error) {
+	token := jwt.New(jwt.SigningMethodHS256)
+	claims := token.Claims.(jwt.MapClaims)
+	claims["iss"] = consts.JWTIssuer
+	claims["sub"] = u.UserName
+	claims["adm"] = u.IsAdmin
+
+	return TouchToken(token)
+}
+
+func getSessionTimeOut() time.Duration {
+	if sessionTimeOut == 0 {
+		sessionTimeOut = conf.Server.SessionTimeout
+		log.Info("Setting Session Timeout", "value", sessionTimeOut)
+	}
+	return sessionTimeOut
+}
+
+func TouchToken(token *jwt.Token) (string, error) {
+	timeout := getSessionTimeOut()
+	expireIn := time.Now().Add(timeout).Unix()
+	claims := token.Claims.(jwt.MapClaims)
+	claims["exp"] = expireIn
+
+	return token.SignedString(JwtSecret)
+}
+
+func Validate(tokenStr string) (jwt.MapClaims, error) {
+	token, err := jwt.Parse(tokenStr, func(token *jwt.Token) (interface{}, error) {
+		// Don't forget to validate the alg is what you expect:
+		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
+			return nil, fmt.Errorf("Unexpected signing method: %v", token.Header["alg"])
+		}
+
+		// hmacSampleSecret is a []byte containing your secret, e.g. []byte("my_secret_key")
+		return JwtSecret, nil
+	})
+	if err != nil {
+		return nil, err
+	}
+	return token.Claims.(jwt.MapClaims), err
+}

core/auth/auth_test.go

@@ -0,0 +1,55 @@
+package auth_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/deluan/navidrome/core/auth"
+	"github.com/deluan/navidrome/log"
+	"github.com/dgrijalva/jwt-go"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestAuth(t *testing.T) {
+	log.SetLevel(log.LevelCritical)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Auth Test Suite")
+}
+
+const testJWTSecret = "not so secret"
+
+var _ = Describe("Auth", func() {
+	BeforeEach(func() {
+		auth.JwtSecret = []byte(testJWTSecret)
+	})
+	Context("Validate", func() {
+		It("returns error with an invalid JWT token", func() {
+			_, err := auth.Validate("invalid.token")
+			Expect(err).To(Not(BeNil()))
+		})
+
+		It("returns the claims from a valid JWT token", func() {
+			token := jwt.New(jwt.SigningMethodHS256)
+			claims := token.Claims.(jwt.MapClaims)
+			claims["iss"] = "issuer"
+			claims["exp"] = time.Now().Add(1 * time.Minute).Unix()
+			tokenStr, _ := token.SignedString(auth.JwtSecret)
+
+			decodedClaims, err := auth.Validate(tokenStr)
+			Expect(err).To(BeNil())
+			Expect(decodedClaims["iss"]).To(Equal("issuer"))
+		})
+
+		It("returns ErrExpired if the `exp` field is in the past", func() {
+			token := jwt.New(jwt.SigningMethodHS256)
+			claims := token.Claims.(jwt.MapClaims)
+			claims["iss"] = "issuer"
+			claims["exp"] = time.Now().Add(-1 * time.Minute).Unix()
+			tokenStr, _ := token.SignedString(auth.JwtSecret)
+
+			_, err := auth.Validate(tokenStr)
+			Expect(err).To(MatchError("Token is expired"))
+		})
+	})
+})

core/common.go

@@ -0,0 +1,15 @@
+package core
+
+import (
+	"context"
+	"github.com/deluan/navidrome/model/request"
+)
+
+func userName(ctx context.Context) string {
+	if user, ok := request.UserFrom(ctx); !ok {
+		return "UNKNOWN"
+	} else {
+		return user.UserName
+	}
+}
+

core/core_suite_test.go

@@ -0,0 +1,35 @@
+package core
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/tests"
+	"github.com/djherbis/fscache"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestEngine(t *testing.T) {
+	tests.Init(t, false)
+	log.SetLevel(log.LevelCritical)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Core Suite")
+}
+
+var testCache fscache.Cache
+var testCacheDir string
+
+var _ = Describe("Core Suite Setup", func() {
+	BeforeSuite(func() {
+		testCacheDir, _ = ioutil.TempDir("", "core_test_cache")
+		fs, _ := fscache.NewFs(testCacheDir, 0755)
+		testCache, _ = fscache.NewCache(fs, nil)
+	})
+
+	AfterSuite(func() {
+		os.RemoveAll(testCacheDir)
+	})
+})

core/cover.go

@@ -0,0 +1,206 @@
+package core
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"image"
+	_ "image/gif"
+	"image/jpeg"
+	_ "image/png"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/deluan/navidrome/conf"
+	"github.com/deluan/navidrome/consts"
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/model"
+	"github.com/deluan/navidrome/resources"
+	"github.com/deluan/navidrome/utils"
+	"github.com/dhowden/tag"
+	"github.com/disintegration/imaging"
+	"github.com/djherbis/fscache"
+)
+
+type Cover interface {
+	Get(ctx context.Context, id string, size int, out io.Writer) error
+}
+
+type ImageCache fscache.Cache
+
+func NewCover(ds model.DataStore, cache ImageCache) Cover {
+	return &cover{ds: ds, cache: cache}
+}
+
+type cover struct {
+	ds    model.DataStore
+	cache fscache.Cache
+}
+
+func (c *cover) Get(ctx context.Context, id string, size int, out io.Writer) error {
+	path, lastUpdate, err := c.getCoverPath(ctx, id)
+	if err != nil && err != model.ErrNotFound {
+		return err
+	}
+
+	// If cache is disabled, just read the coverart directly from file
+	if c.cache == nil {
+		log.Trace(ctx, "Retrieving cover art from file", "path", path, "size", size, err)
+		reader, err := c.getCover(ctx, path, size)
+		if err != nil {
+			log.Error(ctx, "Error loading cover art", "path", path, "size", size, err)
+		} else {
+			_, err = io.Copy(out, reader)
+		}
+		return err
+	}
+
+	cacheKey := imageCacheKey(path, size, lastUpdate)
+	r, w, err := c.cache.Get(cacheKey)
+	if err != nil {
+		log.Error(ctx, "Error reading from image cache", "path", path, "size", size, err)
+		return err
+	}
+	defer r.Close()
+	if w != nil {
+		log.Trace(ctx, "Image cache miss", "path", path, "size", size, "lastUpdate", lastUpdate)
+		go func() {
+			defer w.Close()
+			reader, err := c.getCover(ctx, path, size)
+			if err != nil {
+				log.Error(ctx, "Error loading cover art", "path", path, "size", size, err)
+				return
+			}
+			if _, err := io.Copy(w, reader); err != nil {
+				log.Error(ctx, "Error saving covert art to cache", "path", path, "size", size, err)
+			}
+		}()
+	} else {
+		log.Trace(ctx, "Loading image from cache", "path", path, "size", size, "lastUpdate", lastUpdate)
+	}
+
+	_, err = io.Copy(out, r)
+	return err
+}
+
+func (c *cover) getCoverPath(ctx context.Context, id string) (path string, lastUpdated time.Time, err error) {
+	// If id is an album cover ID
+	if strings.HasPrefix(id, "al-") {
+		log.Trace(ctx, "Looking for album art", "id", id)
+		id = strings.TrimPrefix(id, "al-")
+		var al *model.Album
+		al, err = c.ds.Album(ctx).Get(id)
+		if err != nil {
+			return
+		}
+		if al.CoverArtId == "" {
+			err = model.ErrNotFound
+		}
+		return al.CoverArtPath, al.UpdatedAt, err
+	}
+
+	log.Trace(ctx, "Looking for media file art", "id", id)
+	// if id is a mediafile cover id
+	var mf *model.MediaFile
+	mf, err = c.ds.MediaFile(ctx).Get(id)
+	if err != nil {
+		return
+	}
+	if mf.HasCoverArt {
+		return mf.Path, mf.UpdatedAt, nil
+	}
+
+	// if the mediafile does not have a coverArt, fallback to the album cover
+	log.Trace(ctx, "Media file does not contain art. Falling back to album art", "id", id, "albumId", "al-"+mf.AlbumID)
+	return c.getCoverPath(ctx, "al-"+mf.AlbumID)
+}
+
+func imageCacheKey(path string, size int, lastUpdate time.Time) string {
+	return fmt.Sprintf("%s.%d.%s.%d", path, size, lastUpdate.Format(time.RFC3339Nano), conf.Server.CoverJpegQuality)
+}
+
+func (c *cover) getCover(ctx context.Context, path string, size int) (reader io.Reader, err error) {
+	defer func() {
+		if err != nil {
+			log.Warn(ctx, "Error extracting image", "path", path, "size", size, err)
+			reader, err = resources.AssetFile().Open(consts.PlaceholderAlbumArt)
+		}
+	}()
+
+	if path == "" {
+		return nil, errors.New("empty path given for cover")
+	}
+
+	var data []byte
+	if utils.IsAudioFile(path) {
+		data, err = readFromTag(path)
+	} else {
+		data, err = readFromFile(path)
+	}
+
+	if err != nil {
+		return
+	} else if size > 0 {
+		data, err = resizeImage(bytes.NewReader(data), size)
+	}
+
+	// Confirm the image is valid. Costly, but necessary
+	_, _, err = image.Decode(bytes.NewReader(data))
+	if err == nil {
+		reader = bytes.NewReader(data)
+	}
+
+	return
+}
+
+func resizeImage(reader io.Reader, size int) ([]byte, error) {
+	img, _, err := image.Decode(reader)
+	if err != nil {
+		return nil, err
+	}
+	m := imaging.Resize(img, size, size, imaging.Lanczos)
+	buf := new(bytes.Buffer)
+	err = jpeg.Encode(buf, m, &jpeg.Options{Quality: conf.Server.CoverJpegQuality})
+	return buf.Bytes(), err
+}
+
+func readFromTag(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	m, err := tag.ReadFrom(f)
+	if err != nil {
+		return nil, err
+	}
+
+	picture := m.Picture()
+	if picture == nil {
+		return nil, errors.New("file does not contain embedded art")
+	}
+	return picture.Data, nil
+}
+
+func readFromFile(path string) ([]byte, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+
+	defer f.Close()
+	var buf bytes.Buffer
+	if _, err := buf.ReadFrom(f); err != nil {
+		return nil, err
+	}
+
+	return buf.Bytes(), nil
+}
+
+func NewImageCache() (ImageCache, error) {
+	return newFileCache("Image", conf.Server.ImageCacheSize, consts.ImageCacheDir, consts.DefaultImageCacheMaxItems)
+}

core/cover_test.go

@@ -0,0 +1,136 @@
+package core
+
+import (
+	"bytes"
+	"context"
+	"image"
+
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/model"
+	"github.com/deluan/navidrome/persistence"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("Cover", func() {
+	var cover Cover
+	var ds model.DataStore
+	ctx := log.NewContext(context.TODO())
+
+	BeforeEach(func() {
+		ds = &persistence.MockDataStore{MockedTranscoding: &mockTranscodingRepository{}}
+		ds.Album(ctx).(*persistence.MockAlbum).SetData(`[{"id": "222", "coverArtId": "123", "coverArtPath":"tests/fixtures/test.mp3"}, {"id": "333", "coverArtId": ""}, {"id": "444", "coverArtId": "444", "coverArtPath": "tests/fixtures/cover.jpg"}]`)
+		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(`[{"id": "123", "albumId": "222", "path": "tests/fixtures/test.mp3", "hasCoverArt": true, "updatedAt":"2020-04-02T21:29:31.6377Z"},{"id": "456", "albumId": "222", "path": "tests/fixtures/test.ogg", "hasCoverArt": false, "updatedAt":"2020-04-02T21:29:31.6377Z"}]`)
+	})
+
+	Context("Cache is configured", func() {
+		BeforeEach(func() {
+			cover = NewCover(ds, testCache)
+		})
+
+		It("retrieves the external cover art for an album", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "al-444", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+		})
+
+		It("retrieves the embedded cover art for an album", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "al-222", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+		})
+
+		It("returns the default cover if album does not have cover", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "al-333", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("png"))
+		})
+
+		It("returns the default cover if album is not found", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "al-0101", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("png"))
+		})
+
+		It("retrieves the original cover art from a media_file", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "123", 0, buf)).To(BeNil())
+
+			img, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+			Expect(img.Bounds().Size().X).To(Equal(600))
+			Expect(img.Bounds().Size().Y).To(Equal(600))
+		})
+
+		It("retrieves the album cover art if media_file does not have one", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "456", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+		})
+
+		It("resized cover art as requested", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "123", 200, buf)).To(BeNil())
+
+			img, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+			Expect(img.Bounds().Size().X).To(Equal(200))
+			Expect(img.Bounds().Size().Y).To(Equal(200))
+		})
+
+		Context("Errors", func() {
+			It("returns err if gets error from album table", func() {
+				ds.Album(ctx).(*persistence.MockAlbum).SetError(true)
+				buf := new(bytes.Buffer)
+
+				Expect(cover.Get(ctx, "al-222", 0, buf)).To(MatchError("Error!"))
+			})
+
+			It("returns err if gets error from media_file table", func() {
+				ds.MediaFile(ctx).(*persistence.MockMediaFile).SetError(true)
+				buf := new(bytes.Buffer)
+
+				Expect(cover.Get(ctx, "123", 0, buf)).To(MatchError("Error!"))
+			})
+		})
+	})
+	Context("Cache is NOT configured", func() {
+		BeforeEach(func() {
+			cover = NewCover(ds, nil)
+		})
+
+		It("retrieves the original cover art from an album", func() {
+			buf := new(bytes.Buffer)
+
+			Expect(cover.Get(ctx, "al-222", 0, buf)).To(BeNil())
+
+			_, format, err := image.Decode(bytes.NewReader(buf.Bytes()))
+			Expect(err).To(BeNil())
+			Expect(format).To(Equal("jpeg"))
+		})
+	})
+})

core/file_caches.go

@@ -0,0 +1,32 @@
+package core
+
+import (
+	"fmt"
+	"path/filepath"
+
+	"github.com/deluan/navidrome/conf"
+	"github.com/deluan/navidrome/consts"
+	"github.com/deluan/navidrome/log"
+	"github.com/djherbis/fscache"
+	"github.com/dustin/go-humanize"
+)
+
+func newFileCache(name, cacheSize, cacheFolder string, maxItems int) (fscache.Cache, error) {
+	if cacheSize == "0" {
+		log.Warn(fmt.Sprintf("%s cache disabled", name))
+		return nil, nil
+	}
+	size, err := humanize.ParseBytes(cacheSize)
+	if err != nil {
+		size = consts.DefaultCacheSize
+	}
+	lru := fscache.NewLRUHaunter(maxItems, int64(size), consts.DefaultCacheCleanUpInterval)
+	h := fscache.NewLRUHaunterStrategy(lru)
+	cacheFolder = filepath.Join(conf.Server.DataFolder, cacheFolder)
+	log.Info(fmt.Sprintf("Creating %s cache", name), "path", cacheFolder, "maxSize", humanize.Bytes(size))
+	fs, err := fscache.NewFs(cacheFolder, 0755)
+	if err != nil {
+		return nil, err
+	}
+	return fscache.NewCacheWithHaunter(fs, h)
+}

core/file_caches_test.go

@@ -0,0 +1,37 @@
+package core
+
+import (
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	"github.com/deluan/navidrome/conf"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("File Caches", func() {
+	BeforeEach(func() {
+		conf.Server.DataFolder, _ = ioutil.TempDir("", "file_caches")
+	})
+	AfterEach(func() {
+		os.RemoveAll(conf.Server.DataFolder)
+	})
+
+	Describe("newFileCache", func() {
+		It("creates the cache folder", func() {
+			Expect(newFileCache("test", "1k", "test", 10)).ToNot(BeNil())
+
+			_, err := os.Stat(filepath.Join(conf.Server.DataFolder, "test"))
+			Expect(os.IsNotExist(err)).To(BeFalse())
+		})
+
+		It("creates the cache folder with invalid size", func() {
+			Expect(newFileCache("test", "abc", "test", 10)).ToNot(BeNil())
+		})
+
+		It("returns empty if cache size is '0'", func() {
+			Expect(newFileCache("test", "0", "test", 10)).To(BeNil())
+		})
+	})
+})

core/media_streamer.go

@@ -0,0 +1,222 @@
+package core
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"mime"
+	"os"
+	"time"
+
+	"github.com/deluan/navidrome/conf"
+	"github.com/deluan/navidrome/consts"
+	"github.com/deluan/navidrome/core/transcoder"
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/model"
+	"github.com/deluan/navidrome/model/request"
+	"github.com/djherbis/fscache"
+)
+
+type MediaStreamer interface {
+	NewStream(ctx context.Context, id string, reqFormat string, reqBitRate int) (*Stream, error)
+}
+
+type TranscodingCache fscache.Cache
+
+func NewMediaStreamer(ds model.DataStore, ffm transcoder.Transcoder, cache TranscodingCache) MediaStreamer {
+	return &mediaStreamer{ds: ds, ffm: ffm, cache: cache}
+}
+
+type mediaStreamer struct {
+	ds    model.DataStore
+	ffm   transcoder.Transcoder
+	cache fscache.Cache
+}
+
+func (ms *mediaStreamer) NewStream(ctx context.Context, id string, reqFormat string, reqBitRate int) (*Stream, error) {
+	mf, err := ms.ds.MediaFile(ctx).Get(id)
+	if err != nil {
+		return nil, err
+	}
+
+	var format string
+	var bitRate int
+	var cached bool
+	defer func() {
+		log.Info("Streaming file", "title", mf.Title, "artist", mf.Artist, "format", format, "cached", cached,
+			"bitRate", bitRate, "user", userName(ctx), "transcoding", format != "raw",
+			"originalFormat", mf.Suffix, "originalBitRate", mf.BitRate)
+	}()
+
+	format, bitRate = selectTranscodingOptions(ctx, ms.ds, mf, reqFormat, reqBitRate)
+	log.Trace(ctx, "Selected transcoding options",
+		"requestBitrate", reqBitRate, "requestFormat", reqFormat,
+		"originalBitrate", mf.BitRate, "originalFormat", mf.Suffix,
+		"selectedBitrate", bitRate, "selectedFormat", format,
+	)
+	s := &Stream{ctx: ctx, mf: mf, format: format, bitRate: bitRate}
+
+	if format == "raw" {
+		log.Debug(ctx, "Streaming raw file", "id", mf.ID, "path", mf.Path,
+			"requestBitrate", reqBitRate, "requestFormat", reqFormat,
+			"originalBitrate", mf.BitRate, "originalFormat", mf.Suffix)
+		f, err := os.Open(mf.Path)
+		if err != nil {
+			return nil, err
+		}
+		s.Reader = f
+		s.Closer = f
+		s.Seeker = f
+		s.format = mf.Suffix
+		return s, nil
+	}
+
+	key := cacheKey(id, bitRate, format)
+	r, w, err := ms.cache.Get(key)
+	if err != nil {
+		log.Error(ctx, "Error creating stream caching buffer", "id", mf.ID, err)
+		return nil, err
+	}
+
+	cached = w == nil
+
+	// If this is a brand new transcoding request, not in the cache, start transcoding
+	if !cached {
+		log.Trace(ctx, "Cache miss. Starting new transcoding session", "id", mf.ID)
+		t, err := ms.ds.Transcoding(ctx).FindByFormat(format)
+		if err != nil {
+			log.Error(ctx, "Error loading transcoding command", "format", format, err)
+			return nil, os.ErrInvalid
+		}
+		out, err := ms.ffm.Start(ctx, t.Command, mf.Path, bitRate)
+		if err != nil {
+			log.Error(ctx, "Error starting transcoder", "id", mf.ID, err)
+			return nil, os.ErrInvalid
+		}
+		go copyAndClose(ctx, w, out)
+	}
+
+	// If it is in the cache, check if the stream is done being written. If so, return a ReaderSeeker
+	if cached {
+		size := getFinalCachedSize(r)
+		if size > 0 {
+			log.Debug(ctx, "Streaming cached file", "id", mf.ID, "path", mf.Path,
+				"requestBitrate", reqBitRate, "requestFormat", reqFormat,
+				"originalBitrate", mf.BitRate, "originalFormat", mf.Suffix, "size", size)
+			sr := io.NewSectionReader(r, 0, size)
+			s.Reader = sr
+			s.Closer = r
+			s.Seeker = sr
+			s.format = format
+			return s, nil
+		}
+	}
+
+	log.Debug(ctx, "Streaming transcoded file", "id", mf.ID, "path", mf.Path,
+		"requestBitrate", reqBitRate, "requestFormat", reqFormat,
+		"originalBitrate", mf.BitRate, "originalFormat", mf.Suffix)
+	// All other cases, just return a ReadCloser, without Seek capabilities
+	s.Reader = r
+	s.Closer = r
+	s.format = format
+	return s, nil
+}
+
+func copyAndClose(ctx context.Context, w io.WriteCloser, r io.ReadCloser) {
+	_, err := io.Copy(w, r)
+	if err != nil {
+		log.Error(ctx, "Error copying data to cache", err)
+	}
+	err = r.Close()
+	if err != nil {
+		log.Error(ctx, "Error closing transcode output", err)
+	}
+	err = w.Close()
+	if err != nil {
+		log.Error(ctx, "Error closing cache", err)
+	}
+}
+
+type Stream struct {
+	ctx     context.Context
+	mf      *model.MediaFile
+	bitRate int
+	format  string
+	io.Reader
+	io.Closer
+	io.Seeker
+}
+
+func (s *Stream) Seekable() bool      { return s.Seeker != nil }
+func (s *Stream) Duration() float32   { return s.mf.Duration }
+func (s *Stream) ContentType() string { return mime.TypeByExtension("." + s.format) }
+func (s *Stream) Name() string        { return s.mf.Title + "." + s.format }
+func (s *Stream) ModTime() time.Time  { return s.mf.UpdatedAt }
+func (s *Stream) EstimatedContentLength() int {
+	return int(s.mf.Duration * float32(s.bitRate) / 8 * 1024)
+}
+
+// TODO This function deserves some love (refactoring)
+func selectTranscodingOptions(ctx context.Context, ds model.DataStore, mf *model.MediaFile, reqFormat string, reqBitRate int) (format string, bitRate int) {
+	format = "raw"
+	if reqFormat == "raw" {
+		return
+	}
+	if reqFormat == mf.Suffix && reqBitRate == 0 {
+		bitRate = mf.BitRate
+		return
+	}
+	trc, hasDefault := request.TranscodingFrom(ctx)
+	var cFormat string
+	var cBitRate int
+	if reqFormat != "" {
+		cFormat = reqFormat
+	} else {
+		if hasDefault {
+			cFormat = trc.TargetFormat
+			cBitRate = trc.DefaultBitRate
+			if p, ok := request.PlayerFrom(ctx); ok {
+				cBitRate = p.MaxBitRate
+			}
+		}
+	}
+	if reqBitRate > 0 {
+		cBitRate = reqBitRate
+	}
+	if cBitRate == 0 && cFormat == "" {
+		return
+	}
+	t, err := ds.Transcoding(ctx).FindByFormat(cFormat)
+	if err == nil {
+		format = t.TargetFormat
+		if cBitRate != 0 {
+			bitRate = cBitRate
+		} else {
+			bitRate = t.DefaultBitRate
+		}
+	}
+	if format == mf.Suffix && bitRate >= mf.BitRate {
+		format = "raw"
+		bitRate = 0
+	}
+	return
+}
+
+func cacheKey(id string, bitRate int, format string) string {
+	return fmt.Sprintf("%s.%d.%s", id, bitRate, format)
+}
+
+func getFinalCachedSize(r fscache.ReadAtCloser) int64 {
+	cr, ok := r.(*fscache.CacheReader)
+	if ok {
+		size, final, err := cr.Size()
+		if final && err == nil {
+			return size
+		}
+	}
+	return -1
+}
+
+func NewTranscodingCache() (TranscodingCache, error) {
+	return newFileCache("Transcoding", conf.Server.TranscodingCacheSize, consts.TranscodingCacheDir, consts.DefaultTranscodingCacheMaxItems)
+}

core/media_streamer_test.go

@@ -0,0 +1,198 @@
+package core
+
+import (
+	"context"
+	"io"
+	"strings"
+
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/model"
+	"github.com/deluan/navidrome/model/request"
+	"github.com/deluan/navidrome/persistence"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("MediaStreamer", func() {
+	var streamer MediaStreamer
+	var ds model.DataStore
+	ffmpeg := &fakeFFmpeg{Data: "fake data"}
+	ctx := log.NewContext(context.TODO())
+
+	BeforeEach(func() {
+		ds = &persistence.MockDataStore{MockedTranscoding: &mockTranscodingRepository{}}
+		ds.MediaFile(ctx).(*persistence.MockMediaFile).SetData(`[{"id": "123", "path": "tests/fixtures/test.mp3", "suffix": "mp3", "bitRate": 128, "duration": 257.0}]`)
+		streamer = NewMediaStreamer(ds, ffmpeg, testCache)
+	})
+
+	Context("NewStream", func() {
+		It("returns a seekable stream if format is 'raw'", func() {
+			s, err := streamer.NewStream(ctx, "123", "raw", 0)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(s.Seekable()).To(BeTrue())
+		})
+		It("returns a seekable stream if maxBitRate is 0", func() {
+			s, err := streamer.NewStream(ctx, "123", "mp3", 0)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(s.Seekable()).To(BeTrue())
+		})
+		It("returns a seekable stream if maxBitRate is higher than file bitRate", func() {
+			s, err := streamer.NewStream(ctx, "123", "mp3", 320)
+			Expect(err).ToNot(HaveOccurred())
+			Expect(s.Seekable()).To(BeTrue())
+		})
+		It("returns a NON seekable stream if transcode is required", func() {
+			s, err := streamer.NewStream(ctx, "123", "mp3", 64)
+			Expect(err).To(BeNil())
+			Expect(s.Seekable()).To(BeFalse())
+			Expect(s.Duration()).To(Equal(float32(257.0)))
+		})
+		It("returns a seekable stream if the file is complete in the cache", func() {
+			Eventually(func() bool { return ffmpeg.closed }).Should(BeTrue())
+			s, err := streamer.NewStream(ctx, "123", "mp3", 64)
+			Expect(err).To(BeNil())
+			Expect(s.Seekable()).To(BeTrue())
+		})
+	})
+
+	Context("selectTranscodingOptions", func() {
+		mf := &model.MediaFile{}
+		Context("player is not configured", func() {
+			It("returns raw if raw is requested", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, _ := selectTranscodingOptions(ctx, ds, mf, "raw", 0)
+				Expect(format).To(Equal("raw"))
+			})
+			It("returns raw if a transcoder does not exists", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, _ := selectTranscodingOptions(ctx, ds, mf, "m4a", 0)
+				Expect(format).To(Equal("raw"))
+			})
+			It("returns the requested format if a transcoder exists", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 0)
+				Expect(format).To(Equal("mp3"))
+				Expect(bitRate).To(Equal(160)) // Default Bit Rate
+			})
+			It("returns raw if requested format is the same as the original and it is not necessary to downsample", func() {
+				mf.Suffix = "mp3"
+				mf.BitRate = 112
+				format, _ := selectTranscodingOptions(ctx, ds, mf, "mp3", 128)
+				Expect(format).To(Equal("raw"))
+			})
+			It("returns the requested format if requested BitRate is lower than original", func() {
+				mf.Suffix = "mp3"
+				mf.BitRate = 320
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 192)
+				Expect(format).To(Equal("mp3"))
+				Expect(bitRate).To(Equal(192))
+			})
+			It("returns raw if requested format is the same as the original, but requested BitRate is 0", func() {
+				mf.Suffix = "mp3"
+				mf.BitRate = 320
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 0)
+				Expect(format).To(Equal("raw"))
+				Expect(bitRate).To(Equal(320))
+			})
+		})
+
+		Context("player has format configured", func() {
+			BeforeEach(func() {
+				t := model.Transcoding{ID: "oga1", TargetFormat: "oga", DefaultBitRate: 96}
+				ctx = request.WithTranscoding(ctx, t)
+			})
+			It("returns raw if raw is requested", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, _ := selectTranscodingOptions(ctx, ds, mf, "raw", 0)
+				Expect(format).To(Equal("raw"))
+			})
+			It("returns configured format/bitrate as default", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "", 0)
+				Expect(format).To(Equal("oga"))
+				Expect(bitRate).To(Equal(96))
+			})
+			It("returns requested format", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 0)
+				Expect(format).To(Equal("mp3"))
+				Expect(bitRate).To(Equal(160)) // Default Bit Rate
+			})
+			It("returns requested bitrate", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "", 80)
+				Expect(format).To(Equal("oga"))
+				Expect(bitRate).To(Equal(80))
+			})
+			It("returns raw if selected bitrate and format is the same as original", func() {
+				mf.Suffix = "mp3"
+				mf.BitRate = 192
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 192)
+				Expect(format).To(Equal("raw"))
+				Expect(bitRate).To(Equal(0))
+			})
+		})
+		Context("player has maxBitRate configured", func() {
+			BeforeEach(func() {
+				t := model.Transcoding{ID: "oga1", TargetFormat: "oga", DefaultBitRate: 96}
+				p := model.Player{ID: "player1", TranscodingId: t.ID, MaxBitRate: 80}
+				ctx = request.WithTranscoding(ctx, t)
+				ctx = request.WithPlayer(ctx, p)
+			})
+			It("returns raw if raw is requested", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, _ := selectTranscodingOptions(ctx, ds, mf, "raw", 0)
+				Expect(format).To(Equal("raw"))
+			})
+			It("returns configured format/bitrate as default", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "", 0)
+				Expect(format).To(Equal("oga"))
+				Expect(bitRate).To(Equal(80))
+			})
+			It("returns requested format", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "mp3", 0)
+				Expect(format).To(Equal("mp3"))
+				Expect(bitRate).To(Equal(160)) // Default Bit Rate
+			})
+			It("returns requested bitrate", func() {
+				mf.Suffix = "flac"
+				mf.BitRate = 1000
+				format, bitRate := selectTranscodingOptions(ctx, ds, mf, "", 80)
+				Expect(format).To(Equal("oga"))
+				Expect(bitRate).To(Equal(80))
+			})
+		})
+	})
+})
+
+type fakeFFmpeg struct {
+	Data   string
+	r      io.Reader
+	closed bool
+}
+
+func (ff *fakeFFmpeg) Start(ctx context.Context, cmd, path string, maxBitRate int) (f io.ReadCloser, err error) {
+	ff.r = strings.NewReader(ff.Data)
+	return ff, nil
+}
+
+func (ff *fakeFFmpeg) Read(p []byte) (n int, err error) {
+	return ff.r.Read(p)
+}
+
+func (ff *fakeFFmpeg) Close() error {
+	ff.closed = true
+	return nil
+}

core/mock_transcoding_repo_test.go

@@ -0,0 +1,22 @@
+package core
+
+import "github.com/deluan/navidrome/model"
+
+type mockTranscodingRepository struct {
+	model.TranscodingRepository
+}
+
+func (m *mockTranscodingRepository) Get(id string) (*model.Transcoding, error) {
+	return &model.Transcoding{ID: id, TargetFormat: "mp3", DefaultBitRate: 160}, nil
+}
+
+func (m *mockTranscodingRepository) FindByFormat(format string) (*model.Transcoding, error) {
+	switch format {
+	case "mp3":
+		return &model.Transcoding{ID: "mp31", TargetFormat: "mp3", DefaultBitRate: 160}, nil
+	case "oga":
+		return &model.Transcoding{ID: "oga1", TargetFormat: "oga", DefaultBitRate: 128}, nil
+	default:
+		return nil, model.ErrNotFound
+	}
+}

core/transcoder/ffmpeg.go

@@ -0,0 +1,57 @@
+package transcoder
+
+import (
+	"context"
+	"io"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/deluan/navidrome/log"
+)
+
+type Transcoder interface {
+	Start(ctx context.Context, command, path string, maxBitRate int) (f io.ReadCloser, err error)
+}
+
+func New() Transcoder {
+	path, err := exec.LookPath("ffmpeg")
+	if err != nil {
+		log.Error("Unable to find ffmpeg", err)
+	}
+	log.Debug("Found ffmpeg", "path", path)
+	return &ffmpeg{}
+}
+
+type ffmpeg struct{}
+
+func (ff *ffmpeg) Start(ctx context.Context, command, path string, maxBitRate int) (f io.ReadCloser, err error) {
+	args := createTranscodeCommand(command, path, maxBitRate)
+
+	log.Trace(ctx, "Executing ffmpeg command", "cmd", args)
+	cmd := exec.Command(args[0], args[1:]...) // #nosec
+	cmd.Stderr = os.Stderr
+	if f, err = cmd.StdoutPipe(); err != nil {
+		return
+	}
+	if err = cmd.Start(); err != nil {
+		return
+	}
+
+	go func() { _ = cmd.Wait() }() // prevent zombies
+
+	return
+}
+
+// Path will always be an absolute path
+func createTranscodeCommand(cmd, path string, maxBitRate int) []string {
+	split := strings.Split(cmd, " ")
+	for i, s := range split {
+		s = strings.Replace(s, "%s", path, -1)
+		s = strings.Replace(s, "%b", strconv.Itoa(maxBitRate), -1)
+		split[i] = s
+	}
+
+	return split
+}

core/transcoder/ffmpeg_test.go

@@ -0,0 +1,24 @@
+package transcoder
+
+import (
+	"testing"
+
+	"github.com/deluan/navidrome/log"
+	"github.com/deluan/navidrome/tests"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestTranscoder(t *testing.T) {
+	tests.Init(t, false)
+	log.SetLevel(log.LevelCritical)
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Transcoder Suite")
+}
+
+var _ = Describe("createTranscodeCommand", func() {
+	It("creates a valid command line", func() {
+		args := createTranscodeCommand("ffmpeg -i %s -b:a %bk mp3 -", "/music library/file.mp3", 123)
+		Expect(args).To(Equal([]string{"ffmpeg", "-i", "/music library/file.mp3", "-b:a", "123k", "mp3", "-"}))
+	})
+})

core/wire_providers.go

@@ -0,0 +1,14 @@
+package core
+
+import (
+	"github.com/deluan/navidrome/core/transcoder"
+	"github.com/google/wire"
+)
+
+var Set = wire.NewSet(
+	NewCover,
+	NewMediaStreamer,
+	NewTranscodingCache,
+	NewImageCache,
+	transcoder.New,
+)