Backend: Don't regenerate existing unique IDs

Signed-off-by: Michael Mayer <michael@liquidbytes.net>

internal/entity/album.go

@@ -32,11 +32,11 @@ type Album struct {
 
 // BeforeCreate computes a random UUID when a new album is created in database
 func (m *Album) BeforeCreate(scope *gorm.Scope) error {
-	if err := scope.SetColumn("AlbumUUID", rnd.PPID('a')); err != nil {
-		return err
+	if rnd.IsPPID(m.AlbumUUID, 'a') {
+		return nil
 	}
 
-	return nil
+	return scope.SetColumn("AlbumUUID", rnd.PPID('a'))
 }
 
 // NewAlbum creates a new album; default name is current month and year

internal/entity/file.go

@@ -62,6 +62,10 @@ func FirstFileByHash(fileHash string) (File, error) {
 
 // BeforeCreate computes a random UUID when a new file is created in database
 func (m *File) BeforeCreate(scope *gorm.Scope) error {
+	if rnd.IsPPID(m.FileUUID, 'f') {
+		return nil
+	}
+
 	return scope.SetColumn("FileUUID", rnd.PPID('f'))
 }
 

internal/entity/label.go

@@ -31,12 +31,11 @@ type Label struct {
 
 // BeforeCreate computes a random UUID when a new label is created in database
 func (m *Label) BeforeCreate(scope *gorm.Scope) error {
-	if err := scope.SetColumn("LabelUUID", rnd.PPID('l')); err != nil {
-		log.Errorf("label: %s", err)
-		return err
+	if rnd.IsPPID(m.LabelUUID, 'l') {
+		return nil
 	}
 
-	return nil
+	return scope.SetColumn("LabelUUID", rnd.PPID('l'))
 }
 
 // NewLabel creates a label in database with a given name and priority

internal/entity/photo.go

@@ -146,10 +146,6 @@ func (m *Photo) ClassifyLabels() classify.Labels {
 
 // BeforeCreate computes a unique UUID, and set a default takenAt before indexing a new photo
 func (m *Photo) BeforeCreate(scope *gorm.Scope) error {
-	if err := scope.SetColumn("PhotoUUID", rnd.PPID('p')); err != nil {
-		return err
-	}
-
 	if m.TakenAt.IsZero() || m.TakenAtLocal.IsZero() {
 		now := time.Now()
 
@@ -162,9 +158,13 @@ func (m *Photo) BeforeCreate(scope *gorm.Scope) error {
 		}
 	}
 
+	if rnd.IsPPID(m.PhotoUUID, 'p') {
 		return nil
 	}
 
+	return scope.SetColumn("PhotoUUID", rnd.PPID('p'))
+}
+
 // BeforeSave ensures the existence of TakenAt properties before indexing or updating a photo
 func (m *Photo) BeforeSave(scope *gorm.Scope) error {
 	if m.TakenAt.IsZero() || m.TakenAtLocal.IsZero() {

pkg/rnd/ppid.go

@@ -6,11 +6,20 @@ import (
 )
 
 // PPID returns a unique id with prefix as string.
-func PPID(prefix rune) string {
+func PPID(prefix byte) string {
 	result := make([]byte, 0, 16)
-	result = append(result, byte(prefix))
+	result = append(result, prefix)
 	result = append(result, strconv.FormatInt(time.Now().UTC().Unix(), 36)[0:6]...)
 	result = append(result, Token(9)...)
 
 	return string(result)
 }
+
+// IsPPID returns true if the id seems to be a PhotoPrism unique id.
+func IsPPID(id string, prefix byte) bool {
+	if len(id) != 16 {
+		return false
+	}
+
+	return id[0] == prefix
+}

pkg/rnd/ppid_test.go

@@ -0,0 +1,32 @@
+package rnd
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPPID(t *testing.T) {
+	for n := 0; n < 5; n++ {
+		uuid := PPID('x')
+		t.Logf("id: %s", uuid)
+		assert.Equal(t, len(uuid), 16)
+	}
+}
+
+func BenchmarkPPID(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		PPID('x')
+	}
+}
+
+func TestIsPPID(t *testing.T) {
+	prefix := byte('x')
+
+	for n := 0; n < 10; n++ {
+		id := PPID(prefix)
+		assert.True(t, IsPPID(id, prefix))
+	}
+
+	assert.True(t, IsPPID("lt9k3pw1wowuy3c2", 'l'))
+}

pkg/rnd/token_test.go

@@ -54,17 +54,3 @@ func BenchmarkRandomToken3(b *testing.B) {
 		Token(3)
 	}
 }
-
-func TestPPID(t *testing.T) {
-	for n := 0; n < 5; n++ {
-		uuid := PPID('x')
-		t.Logf("id: %s", uuid)
-		assert.Equal(t, len(uuid), 16)
-	}
-}
-
-func BenchmarkPPID(b *testing.B) {
-	for n := 0; n < b.N; n++ {
-		PPID('x')
-	}
-}