fix: some error

Author: sunls24

ent/envelope/envelope.go

@@ -18,8 +18,8 @@ func (Envelope) Fields() []ent.Field {
 	return []ent.Field{
 		field.String("to").NotEmpty(),
 		field.String("from").NotEmpty(),
-		field.String("subject").NotEmpty().Default("no subject"),
-		field.String("content").NotEmpty().Default("no content"),
+		field.String("subject").Default("no subject"),
+		field.String("content").Default("no content"),
 		field.Time("created_at").Default(time.Now),
 	}
 }

ent/envelope_create.go

@@ -66,7 +66,7 @@ func saveAttachment(ctx *Context, attachments []*enmime.Part, to string, ownerID
 		}
 
 		_, err := ctx.ent.Attachment.Create().
-			SetID(filepath.Base(dir) + name[:16]).
+			SetID(filepath.Base(dir) + name[:6] + utils.RandomStr(4)).
 			SetFilename(a.FileName).
 			SetFilepath(fp).
 			SetContentType(a.ContentType).

ent/envelope_update.go

@@ -3,10 +3,29 @@ package utils
 import (
 	"crypto/md5"
 	"encoding/hex"
+	"math/rand/v2"
+	"unsafe"
 )
 
 func Md5(str string) string {
 	h := md5.New()
 	h.Write([]byte(str))
 	return hex.EncodeToString(h.Sum(nil))
 }
+
+func RandomStr(length int) string {
+	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	b := make([]byte, length)
+	for i := range b {
+		b[i] = charset[rand.IntN(len(charset))]
+	}
+	return Bytes2Str(b)
+}
+
+func Str2Bytes(str string) []byte {
+	return unsafe.Slice(unsafe.StringData(str), len(str))
+}
+
+func Bytes2Str(b []byte) string {
+	return unsafe.String(unsafe.SliceData(b), len(b))
+}