Move alternative tag names mapping to metadata

scanner/metadata/taglib/taglib.go

@@ -24,6 +24,15 @@ func (e *Extractor) Parse(paths ...string) (map[string]metadata.ParsedTags, erro
 	return fileTags, nil
 }
 
+func (e *Extractor) CustomMappings() metadata.ParsedTags {
+	return metadata.ParsedTags{
+		"title":       {"titlesort"},
+		"album":       {"albumsort"},
+		"artist":      {"artistsort"},
+		"tracknumber": {"trck", "_track"},
+	}
+}
+
 func (e *Extractor) extractMetadata(filePath string) (metadata.ParsedTags, error) {
 	tags, err := Read(filePath)
 	if err != nil {
@@ -31,13 +40,6 @@ func (e *Extractor) extractMetadata(filePath string) (metadata.ParsedTags, error
 		return nil, err
 	}
 
-	alternativeTags := map[string][]string{
-		"title":       {"titlesort"},
-		"album":       {"albumsort"},
-		"artist":      {"artistsort"},
-		"tracknumber": {"trck", "_track"},
-	}
-
 	if length, ok := tags["lengthinmilliseconds"]; ok && len(length) > 0 {
 		millis, _ := strconv.Atoi(length[0])
 		if duration := float64(millis) / 1000.0; duration > 0 {
@@ -45,13 +47,6 @@ func (e *Extractor) extractMetadata(filePath string) (metadata.ParsedTags, error
 		}
 	}
 
-	for tagName, alternatives := range alternativeTags {
-		for _, altName := range alternatives {
-			if altValue, ok := tags[altName]; ok {
-				tags[tagName] = append(tags[tagName], altValue...)
-			}
-		}
-	}
 	return tags, nil
 }
 

scanner/metadata/taglib/taglib_test.go

@@ -42,7 +42,6 @@ var _ = Describe("Extractor", func() {
 			Expect(m).To(HaveKeyWithValue("tcmp", []string{"1"})) // Compilation
 			Expect(m).To(HaveKeyWithValue("genre", []string{"Rock"}))
 			Expect(m).To(HaveKeyWithValue("date", []string{"2014", "2014"}))
-			Expect(m).To(HaveKeyWithValue("tracknumber", []string{"2/10", "2/10", "2"}))
 			Expect(m).To(HaveKeyWithValue("discnumber", []string{"1/2"}))
 			Expect(m).To(HaveKeyWithValue("has_picture", []string{"true"}))
 			Expect(m).To(HaveKeyWithValue("duration", []string{"1.02"}))
@@ -52,6 +51,10 @@ var _ = Describe("Extractor", func() {
 			Expect(m).To(HaveKeyWithValue("lyrics", []string{"Lyrics 1\rLyrics 2"}))
 			Expect(m).To(HaveKeyWithValue("bpm", []string{"123"}))
 
+			Expect(m).To(HaveKeyWithValue("tracknumber", []string{"2/10"}))
+			m = m.Map(e.CustomMappings())
+			Expect(m).To(HaveKeyWithValue("tracknumber", []string{"2/10", "2/10", "2"}))
+
 			m = mds["tests/fixtures/test.ogg"]
 			Expect(err).To(BeNil())
 			Expect(m).ToNot(HaveKey("title"))