fix: fix memory allocation on media library refresh

README.md

@@ -16,6 +16,13 @@ docker run -d -p 8080:8080 -v /path/to/your/music:/music darep/beatstream:latest
 
 Open http://0.0.0.0:8080 on your browser. Log in and wait when indexing ends, refresh page and happy listening!
 
+For very large libraries, you can give Go a soft memory limit while leaving headroom for TagLib and the rest of the
+container. For example, with a 1 GiB container limit:
+
+```bash
+docker run -d --memory=1g -e GOMEMLIMIT=900MiB -p 8080:8080 -v /path/to/your/music:/music darep/beatstream:latest
+```
+
 ### Manual Install
 
 Requirements: Go 1.22 or newer. Node.js 20 or newer. TagLib (C bindings) e.g. libtagc

api.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"bufio"
 	"encoding/json"
+	"io"
 	"io/fs"
 	"net/http"
 	"os"
@@ -267,7 +269,7 @@ func refreshSongs() error {
 
 	// Sort songs
 	sort.Slice(songs, func(i, j int) bool {
-		return songs[i].ToNaturalSortString() < songs[j].ToNaturalSortString()
+		return compareSongs(&songs[i], &songs[j]) < 0
 	})
 
 	// lock "songs.json" so that it's not read while being written
@@ -282,10 +284,29 @@ func refreshSongs() error {
 	defer file.Close()
 
 	logger.Log.Println("Writing songs to file…")
-	err = json.NewEncoder(file).Encode(songs)
-	if err != nil {
+	return writeSongsJSON(file, songs)
+}
+
+func writeSongsJSON(w io.Writer, songs []Song) error {
+	buffer := bufio.NewWriter(w)
+	if err := buffer.WriteByte('['); err != nil {
 		return err
 	}
 
-	return nil
+	encoder := json.NewEncoder(buffer)
+	for i := range songs {
+		if i > 0 {
+			if err := buffer.WriteByte(','); err != nil {
+				return err
+			}
+		}
+		if err := encoder.Encode(&songs[i]); err != nil {
+			return err
+		}
+	}
+
+	if err := buffer.WriteByte(']'); err != nil {
+		return err
+	}
+	return buffer.Flush()
 }

api_test.go

@@ -1,6 +1,11 @@
 package main
 
-import "testing"
+import (
+	"bytes"
+	"encoding/json"
+	"reflect"
+	"testing"
+)
 
 func TestDeleteOtherSessions(t *testing.T) {
 	sessions = []Session{
@@ -15,3 +20,21 @@ func TestDeleteOtherSessions(t *testing.T) {
 		t.Fatalf("unexpected remaining sessions: %#v", sessions)
 	}
 }
+
+func TestWriteSongsJSON(t *testing.T) {
+	track := 3
+	want := []Song{{Filename: "song.mp3", Path: "/song.mp3", Title: "Song", Artist: "Artist", TrackNum: &track, Length: 90}}
+	var output bytes.Buffer
+
+	if err := writeSongsJSON(&output, want); err != nil {
+		t.Fatal(err)
+	}
+
+	var got []Song
+	if err := json.Unmarshal(output.Bytes(), &got); err != nil {
+		t.Fatalf("invalid JSON %q: %v", output.String(), err)
+	}
+	if !reflect.DeepEqual(got, want) {
+		t.Fatalf("got %#v, want %#v", got, want)
+	}
+}

go.mod

@@ -5,5 +5,4 @@ go 1.23.5
 require (
 	github.com/go-chi/chi/v5 v5.2.3
 	github.com/joho/godotenv v1.5.1
-	github.com/wtolson/go-taglib v0.0.0-20210406152913-79209c280058
 )

go.sum

@@ -2,5 +2,3 @@ github.com/go-chi/chi/v5 v5.2.3 h1:WQIt9uxdsAbgIYgid+BpYc+liqQZGMHRaUwp0JUcvdE=
 github.com/go-chi/chi/v5 v5.2.3/go.mod h1:L2yAIGWB3H+phAw1NxKwWM+7eUH/lU8pOMm5hHcoops=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
-github.com/wtolson/go-taglib v0.0.0-20210406152913-79209c280058 h1:/kj9W8wSHTlwt/i4n6902i/YOPYNIXiDR/PAmgbrDyc=
-github.com/wtolson/go-taglib v0.0.0-20210406152913-79209c280058/go.mod h1:p+WHGfN/a+Ol37Pm7EIOO/6Cylieb2qn1jmKfxtSsUg=

helpers.go

@@ -7,7 +7,7 @@ import (
 	"strings"
 
 	"github.com/Darep/Beatstream/logger"
-	tag "github.com/wtolson/go-taglib"
+	tag "github.com/Darep/Beatstream/taglib"
 )
 
 // Helper for responding as JSON

song.go

@@ -1,9 +1,9 @@
 package main
 
 import (
+	"cmp"
 	"encoding/json"
 	"fmt"
-	"strings"
 )
 
 type Song struct {
@@ -16,27 +16,26 @@ type Song struct {
 	Length   int    `json:"length"`
 }
 
-// For sorting songs in a natural way (artist, album, track number)
-func (song *Song) ToNaturalSortString() string {
-	sortables := []string{}
-
-	if song.Artist != "" {
-		sortables = append(sortables, song.Artist)
+func compareSongs(a, b *Song) int {
+	if result := cmp.Compare(a.Artist, b.Artist); result != 0 {
+		return result
 	}
-	if song.Album != "" {
-		sortables = append(sortables, song.Album)
+	if result := cmp.Compare(a.Album, b.Album); result != 0 {
+		return result
 	}
-	if song.TrackNum == nil {
-		sortables = append(sortables, song.Title)
-	} else {
-		sortables = append(sortables, fmt.Sprintf("%03d", *song.TrackNum))
+	if a.TrackNum != nil && b.TrackNum != nil {
+		if result := cmp.Compare(*a.TrackNum, *b.TrackNum); result != 0 {
+			return result
+		}
+	} else if a.TrackNum != nil {
+		return -1
+	} else if b.TrackNum != nil {
+		return 1
 	}
-
-	if len(sortables) > 0 {
-		return strings.Join(sortables, " ")
+	if result := cmp.Compare(a.Title, b.Title); result != 0 {
+		return result
 	}
-
-	return song.Filename
+	return cmp.Compare(a.Filename, b.Filename)
 }
 
 // Return a nice title for the song, like "Artist - Title". Fallback to the filename

song_test.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"sort"
+	"testing"
+)
+
+func TestCompareSongs(t *testing.T) {
+	one, two := 1, 2
+	songs := []Song{
+		{Artist: "B", Album: "Album", TrackNum: &one, Title: "First"},
+		{Artist: "A", Album: "Album", Title: "No track"},
+		{Artist: "A", Album: "Album", TrackNum: &two, Title: "Second"},
+		{Artist: "A", Album: "Album", TrackNum: &one, Title: "First"},
+	}
+
+	sort.Slice(songs, func(i, j int) bool { return compareSongs(&songs[i], &songs[j]) < 0 })
+
+	if songs[0].Title != "First" || songs[1].Title != "Second" || songs[2].Title != "No track" || songs[3].Artist != "B" {
+		t.Fatalf("unexpected order: %#v", songs)
+	}
+}

taglib/LICENSE

@@ -0,0 +1,11 @@
+Copyright 2012-2021 William Trevor Olson
+
+Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

taglib/taglib.go

@@ -0,0 +1,101 @@
+package taglib
+
+// #cgo pkg-config: taglib
+// #cgo LDFLAGS: -ltag_c
+// #include <stdlib.h>
+// #include <tag_c.h>
+import "C"
+
+import (
+	"errors"
+	"sync"
+	"time"
+	"unsafe"
+)
+
+var (
+	ErrInvalid = errors.New("invalid file")
+	mutex      sync.Mutex
+)
+
+type File struct {
+	file       *C.TagLib_File
+	tag        *C.TagLib_Tag
+	properties *C.TagLib_AudioProperties
+}
+
+func init() {
+	C.taglib_id3v2_set_default_text_encoding(3)
+	C.taglib_set_string_management_enabled(0)
+}
+
+func Read(filename string) (*File, error) {
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	name := C.CString(filename)
+	defer C.free(unsafe.Pointer(name))
+
+	file := C.taglib_file_new(name)
+	if file == nil {
+		return nil, ErrInvalid
+	}
+	if C.taglib_file_is_valid(file) == 0 {
+		C.taglib_file_free(file)
+		return nil, ErrInvalid
+	}
+
+	return &File{
+		file:       file,
+		tag:        C.taglib_file_tag(file),
+		properties: C.taglib_file_audioproperties(file),
+	}, nil
+}
+
+func (file *File) Close() {
+	mutex.Lock()
+	defer mutex.Unlock()
+
+	C.taglib_file_free(file.file)
+	file.file = nil
+	file.tag = nil
+	file.properties = nil
+}
+
+func (file *File) Title() string {
+	mutex.Lock()
+	defer mutex.Unlock()
+	return goString(C.taglib_tag_title(file.tag))
+}
+
+func (file *File) Artist() string {
+	mutex.Lock()
+	defer mutex.Unlock()
+	return goString(C.taglib_tag_artist(file.tag))
+}
+
+func (file *File) Album() string {
+	mutex.Lock()
+	defer mutex.Unlock()
+	return goString(C.taglib_tag_album(file.tag))
+}
+
+func (file *File) Track() int {
+	mutex.Lock()
+	defer mutex.Unlock()
+	return int(C.taglib_tag_track(file.tag))
+}
+
+func (file *File) Length() time.Duration {
+	mutex.Lock()
+	defer mutex.Unlock()
+	return time.Duration(C.taglib_audioproperties_length(file.properties)) * time.Second
+}
+
+func goString(value *C.char) string {
+	if value == nil {
+		return ""
+	}
+	defer C.free(unsafe.Pointer(value))
+	return C.GoString(value)
+}

taglib/taglib_test.go

@@ -0,0 +1,14 @@
+package taglib
+
+import (
+	"errors"
+	"path/filepath"
+	"testing"
+)
+
+func TestReadMissingFile(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "missing.mp3")
+	if _, err := Read(path); !errors.Is(err, ErrInvalid) {
+		t.Fatalf("got %v, want %v", err, ErrInvalid)
+	}
+}