Invert dependency of metadata and extractors

scanner/metadata/ffmpeg/ffmpeg.go

@@ -11,19 +11,20 @@ import (
 
 	"github.com/navidrome/navidrome/conf"
 	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/scanner/metadata"
 )
 
-type Parser struct{}
+const ExtractorID = "ffmpeg"
 
-type parsedTags = map[string][]string
+type Extractor struct{}
 
-func (e *Parser) Parse(files ...string) (map[string]parsedTags, error) {
+func (e *Extractor) Parse(files ...string) (map[string]metadata.ParsedTags, error) {
 	args := e.createProbeCommand(files)
 
 	log.Trace("Executing command", "args", args)
 	cmd := exec.Command(args[0], args[1:]...) // #nosec
 	output, _ := cmd.CombinedOutput()
-	fileTags := map[string]parsedTags{}
+	fileTags := map[string]metadata.ParsedTags{}
 	if len(output) == 0 {
 		return fileTags, errors.New("error extracting metadata files")
 	}
@@ -38,7 +39,7 @@ func (e *Parser) Parse(files ...string) (map[string]parsedTags, error) {
 	return fileTags, nil
 }
 
-func (e *Parser) extractMetadata(filePath, info string) (parsedTags, error) {
+func (e *Extractor) extractMetadata(filePath, info string) (metadata.ParsedTags, error) {
 	tags := e.parseInfo(info)
 	if len(tags) == 0 {
 		log.Trace("Not a media file. Skipping", "filePath", filePath)
@@ -83,7 +84,7 @@ var (
 	coverRx = regexp.MustCompile(`^\s{2,4}Stream #\d+:\d+: (Video):.*`)
 )
 
-func (e *Parser) parseOutput(output string) map[string]string {
+func (e *Extractor) parseOutput(output string) map[string]string {
 	outputs := map[string]string{}
 	all := inputRegex.FindAllStringSubmatchIndex(output, -1)
 	for i, loc := range all {
@@ -105,7 +106,7 @@ func (e *Parser) parseOutput(output string) map[string]string {
 	return outputs
 }
 
-func (e *Parser) parseInfo(info string) map[string][]string {
+func (e *Extractor) parseInfo(info string) map[string][]string {
 	tags := map[string][]string{}
 
 	reader := strings.NewReader(info)
@@ -176,7 +177,7 @@ func (e *Parser) parseInfo(info string) map[string][]string {
 
 var zeroTime = time.Date(0000, time.January, 1, 0, 0, 0, 0, time.UTC)
 
-func (e *Parser) parseDuration(tag string) string {
+func (e *Extractor) parseDuration(tag string) string {
 	d, err := time.Parse("15:04:05", tag)
 	if err != nil {
 		return "0"
@@ -184,7 +185,7 @@ func (e *Parser) parseDuration(tag string) string {
 	return strconv.FormatFloat(d.Sub(zeroTime).Seconds(), 'f', 2, 32)
 }
 
-func (e *Parser) parseChannels(tag string) string {
+func (e *Extractor) parseChannels(tag string) string {
 	if tag == "mono" {
 		return "1"
 	} else if tag == "stereo" {
@@ -199,7 +200,7 @@ func (e *Parser) parseChannels(tag string) string {
 }
 
 // Inputs will always be absolute paths
-func (e *Parser) createProbeCommand(inputs []string) []string {
+func (e *Extractor) createProbeCommand(inputs []string) []string {
 	split := strings.Split(conf.Server.ProbeCommand, " ")
 	args := make([]string, 0)
 
@@ -214,3 +215,7 @@ func (e *Parser) createProbeCommand(inputs []string) []string {
 	}
 	return args
 }
+
+func init() {
+	metadata.RegisterExtractor(ExtractorID, &Extractor{})
+}

scanner/metadata/ffmpeg/ffmpeg_test.go

@@ -5,10 +5,10 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-var _ = Describe("Parser", func() {
+var _ = Describe("Extractor", func() {
-	var e *Parser
+	var e *Extractor
 	BeforeEach(func() {
-		e = &Parser{}
+		e = &Extractor{}
 	})
 
 	Context("extractMetadata", func() {

scanner/metadata/metadata.go

@@ -14,25 +14,26 @@ import (
 	"github.com/navidrome/navidrome/conf"
 	"github.com/navidrome/navidrome/consts"
 	"github.com/navidrome/navidrome/log"
-	"github.com/navidrome/navidrome/scanner/metadata/ffmpeg"
-	"github.com/navidrome/navidrome/scanner/metadata/taglib"
 )
 
-type Parser interface {
+type ParsedTags = map[string][]string
-	Parse(files ...string) (map[string]map[string][]string, error)
+
+type Extractor interface {
+	Parse(files ...string) (map[string]ParsedTags, error)
 }
 
-var parsers = map[string]Parser{
+var extractors = map[string]Extractor{}
-	"ffmpeg": &ffmpeg.Parser{},
+
-	"taglib": &taglib.Parser{},
+func RegisterExtractor(id string, parser Extractor) {
+	extractors[id] = parser
 }
 
 func Extract(files ...string) (map[string]Tags, error) {
-	p, ok := parsers[conf.Server.Scanner.Extractor]
+	p, ok := extractors[conf.Server.Scanner.Extractor]
 	if !ok {
 		log.Warn("Invalid 'Scanner.Extractor' option. Using default", "requested", conf.Server.Scanner.Extractor,
 			"validOptions", "ffmpeg,taglib", "default", consts.DefaultScannerExtractor)
-		p = parsers[consts.DefaultScannerExtractor]
+		p = extractors[consts.DefaultScannerExtractor]
 	}
 
 	extractedTags, err := p.Parse(files...)

scanner/metadata/taglib/taglib.go

@@ -6,14 +6,15 @@ import (
 	"strconv"
 
 	"github.com/navidrome/navidrome/log"
+	"github.com/navidrome/navidrome/scanner/metadata"
 )
 
-type Parser struct{}
+const ExtractorID = "taglib"
 
-type parsedTags = map[string][]string
+type Extractor struct{}
 
-func (e *Parser) Parse(paths ...string) (map[string]parsedTags, error) {
+func (e *Extractor) Parse(paths ...string) (map[string]metadata.ParsedTags, error) {
-	fileTags := map[string]parsedTags{}
+	fileTags := map[string]metadata.ParsedTags{}
 	for _, path := range paths {
 		tags, err := e.extractMetadata(path)
 		if !errors.Is(err, os.ErrPermission) {
@@ -23,7 +24,7 @@ func (e *Parser) Parse(paths ...string) (map[string]parsedTags, error) {
 	return fileTags, nil
 }
 
-func (e *Parser) extractMetadata(filePath string) (parsedTags, error) {
+func (e *Extractor) extractMetadata(filePath string) (metadata.ParsedTags, error) {
 	tags, err := Read(filePath)
 	if err != nil {
 		log.Warn("TagLib: Error reading metadata from file. Skipping", "filePath", filePath, err)
@@ -53,3 +54,7 @@ func (e *Parser) extractMetadata(filePath string) (parsedTags, error) {
 	}
 	return tags, nil
 }
+
+func init() {
+	metadata.RegisterExtractor(ExtractorID, &Extractor{})
+}

scanner/metadata/taglib/taglib_test.go

@@ -8,13 +8,13 @@ import (
 	. "github.com/onsi/gomega"
 )
 
-var _ = Describe("Parser", func() {
+var _ = Describe("Extractor", func() {
-	var e *Parser
+	var e *Extractor
 	// This file will have 0222 (no read) permission during these tests
 	var accessForbiddenFile = "tests/fixtures/test_no_read_permission.ogg"
 
 	BeforeEach(func() {
-		e = &Parser{}
+		e = &Extractor{}
 
 		err := os.Chmod(accessForbiddenFile, 0222)
 		Expect(err).ToNot(HaveOccurred())

scanner/tag_scanner.go

@@ -16,6 +16,8 @@ import (
 	"github.com/navidrome/navidrome/model"
 	"github.com/navidrome/navidrome/model/request"
 	"github.com/navidrome/navidrome/scanner/metadata"
+	_ "github.com/navidrome/navidrome/scanner/metadata/ffmpeg"
+	_ "github.com/navidrome/navidrome/scanner/metadata/taglib"
 	"github.com/navidrome/navidrome/utils"
 )