feat: add max download size validation for media files

- settings.go: add WhatsappSettingMaxDownloadSize for file size
  validation (500MB)
- utils.go: check file size before writing media to disk, returning
  an error if it exceeds the max limit

src/config/settings.go

@@ -25,6 +25,7 @@ var (
 	WhatsappLogLevel                     = "ERROR"
 	WhatsappSettingMaxFileSize     int64 = 50000000  // 50MB
 	WhatsappSettingMaxVideoSize    int64 = 100000000 // 100MB
+	WhatsappSettingMaxDownloadSize int64 = 500000000 // 500MB
 	WhatsappTypeUser                     = "@s.whatsapp.net"
 	WhatsappTypeGroup                    = "@g.us"
 	WhatsappAccountValidation            = true

src/pkg/whatsapp/utils.go

@@ -34,6 +34,12 @@ func ExtractMedia(storageLocation string, mediaFile whatsmeow.DownloadableMessag
 		return extractedMedia, err
 	}
 
+	// Validate file size before writing to disk
+	maxFileSize := config.WhatsappSettingMaxDownloadSize
+	if int64(len(data)) > maxFileSize {
+		return extractedMedia, fmt.Errorf("file size exceeds the maximum limit of %d bytes", maxFileSize)
+	}
+
 	switch media := mediaFile.(type) {
 	case *waE2E.ImageMessage:
 		extractedMedia.MimeType = media.GetMimetype()