Allow translations to be overridden in the data folder

server/app/translations.go

@@ -10,9 +10,11 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/deluan/navidrome/conf"
 	"github.com/deluan/navidrome/consts"
 	"github.com/deluan/navidrome/log"
 	"github.com/deluan/navidrome/resources"
+	"github.com/deluan/navidrome/utils"
 	"github.com/deluan/rest"
 )
 
@@ -28,7 +30,10 @@ var (
 )
 
 func newTranslationRepository(context.Context) rest.Repository {
-	dir := resources.AssetFile()
+	dir := utils.NewMergeFS(
+		resources.AssetFile(),
+		http.Dir(filepath.Join(conf.Server.DataFolder, "resources")),
+	)
 	if err := loadTranslations(dir); err != nil {
 		log.Error("Error loading translation files", err)
 	}

utils/merge_fs.go

@@ -0,0 +1,108 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"sort"
+)
+
+type MergeFS struct {
+	base    http.FileSystem
+	overlay http.FileSystem
+}
+
+func NewMergeFS(base, overlay http.FileSystem) http.FileSystem {
+	return &MergeFS{
+		base:    base,
+		overlay: overlay,
+	}
+}
+
+func (m MergeFS) Open(name string) (http.File, error) {
+	f, err := m.overlay.Open(name)
+	if err != nil {
+		return m.base.Open(name)
+	}
+
+	info, err := f.Stat()
+	if err != nil {
+		_ = f.Close()
+		return m.base.Open(name)
+	}
+
+	if !info.IsDir() {
+		return f, nil
+	}
+
+	baseDir, _ := m.base.Open(name)
+	defer func() {
+		_ = baseDir.Close()
+		_ = f.Close()
+	}()
+	return m.mergeDirs(name, info, baseDir, f)
+}
+
+func (m MergeFS) mergeDirs(name string, info os.FileInfo, baseDir http.File, overlayDir http.File) (http.File, error) {
+	merged := map[string]os.FileInfo{}
+
+	baseFiles, err := baseDir.Readdir(-1)
+	if err != nil {
+		return nil, err
+	}
+	sort.Slice(baseFiles, func(i, j int) bool { return baseFiles[i].Name() < baseFiles[j].Name() })
+
+	overlayFiles, err := overlayDir.Readdir(-1)
+	if err != nil {
+		overlayFiles = nil
+	}
+	sort.Slice(overlayFiles, func(i, j int) bool { return overlayFiles[i].Name() < overlayFiles[j].Name() })
+
+	for _, f := range baseFiles {
+		merged[f.Name()] = f
+	}
+	for _, f := range overlayFiles {
+		merged[f.Name()] = f
+	}
+
+	var entries []os.FileInfo
+	for _, i := range merged {
+		entries = append(entries, i)
+	}
+
+	sort.Slice(entries, func(i, j int) bool { return entries[i].Name() < entries[j].Name() })
+	return &mergedDir{
+		name:    name,
+		info:    info,
+		entries: entries,
+	}, nil
+}
+
+type mergedDir struct {
+	name    string
+	info    os.FileInfo
+	entries []os.FileInfo
+	pos     int
+}
+
+func (d mergedDir) Readdir(count int) ([]os.FileInfo, error) {
+	if d.pos >= len(d.entries) && count > 0 {
+		return nil, io.EOF
+	}
+	if count <= 0 || count > len(d.entries)-d.pos {
+		count = len(d.entries) - d.pos
+	}
+	e := d.entries[d.pos : d.pos+count]
+	d.pos += count
+	return e, nil
+}
+
+func (d mergedDir) Close() error               { return nil }
+func (d mergedDir) Stat() (os.FileInfo, error) { return d.info, nil }
+func (d mergedDir) Read(p []byte) (n int, err error) {
+	return 0, fmt.Errorf("cannot Read from directory %s", d.name)
+}
+func (d mergedDir) Seek(offset int64, whence int) (int64, error) {
+	return 0, fmt.Errorf("unsupported Seek in directory %s", d.name)
+}

utils/merge_fs_test.go

@@ -0,0 +1,89 @@
+package utils_test
+
+import (
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+
+	"github.com/deluan/navidrome/utils"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("MergeFS", func() {
+	var baseName, overlayName string
+	var baseDir, overlayDir, mergedDir http.FileSystem
+
+	BeforeEach(func() {
+		baseName, _ = ioutil.TempDir("", "merge_fs_base_test")
+		overlayName, _ = ioutil.TempDir("", "merge_fs_overlay_test")
+		baseDir = http.Dir(baseName)
+		overlayDir = http.Dir(overlayName)
+		mergedDir = utils.NewMergeFS(baseDir, overlayDir)
+	})
+
+	It("reads from base dir if not found in overlay", func() {
+		_f(baseName, "a.json")
+		file, err := mergedDir.Open("a.json")
+		Expect(err).To(BeNil())
+
+		stat, err := file.Stat()
+		Expect(err).To(BeNil())
+
+		Expect(stat.Name()).To(Equal("a.json"))
+	})
+
+	It("reads overridden file", func() {
+		_f(baseName, "b.json", "original")
+		_f(baseName, "b.json", "overridden")
+
+		file, err := mergedDir.Open("b.json")
+		Expect(err).To(BeNil())
+
+		content, err := ioutil.ReadAll(file)
+		Expect(err).To(BeNil())
+		Expect(string(content)).To(Equal("overridden"))
+	})
+
+	It("reads only files from base if overlay is empty", func() {
+		_f(baseName, "test.txt")
+
+		dir, err := mergedDir.Open(".")
+		Expect(err).To(BeNil())
+
+		list, err := dir.Readdir(-1)
+		Expect(err).To(BeNil())
+
+		Expect(list).To(HaveLen(1))
+		Expect(list[0].Name()).To(Equal("test.txt"))
+	})
+
+	It("reads merged dirs", func() {
+		_f(baseName, "1111.txt")
+		_f(overlayName, "2222.json")
+
+		dir, err := mergedDir.Open(".")
+		Expect(err).To(BeNil())
+
+		list, err := dir.Readdir(-1)
+		Expect(err).To(BeNil())
+
+		Expect(list).To(HaveLen(2))
+		Expect(list[0].Name()).To(Equal("1111.txt"))
+		Expect(list[1].Name()).To(Equal("2222.json"))
+	})
+})
+
+func _f(dir, name string, content ...string) string {
+	path := filepath.Join(dir, name)
+	file, err := os.Create(path)
+	if err != nil {
+		panic(err)
+	}
+	if len(content) > 0 {
+		_, _ = file.WriteString(content[0])
+	}
+	_ = file.Close()
+	return path
+}