fix: add option to manually select SMTP TLS method (#268)

Co-authored-by: Elias Schneider <login@eliasschneider.com>

backend/internal/dto/app_config_dto.go

@@ -21,7 +21,7 @@ type AppConfigUpdateDto struct {
 	SmtpFrom                           string `json:"smtpFrom" binding:"omitempty,email"`
 	SmtpUser                           string `json:"smtpUser"`
 	SmtpPassword                       string `json:"smtpPassword"`
-	SmtpTls                            string `json:"smtpTls"`
+	SmtpTls                            string `json:"smtpTls" binding:"required,oneof=none starttls tls"`
 	SmtpSkipCertVerify                 string `json:"smtpSkipCertVerify"`
 	LdapEnabled                        string `json:"ldapEnabled" binding:"required"`
 	LdapUrl                            string `json:"ldapUrl"`

backend/internal/service/app_config_service.go

@@ -27,6 +27,7 @@ func NewAppConfigService(db *gorm.DB) *AppConfigService {
 	if err := service.InitDbConfig(); err != nil {
 		log.Fatalf("Failed to initialize app config service: %v", err)
 	}
+
 	return service
 }
 
@@ -96,8 +97,8 @@ var defaultDbConfig = model.AppConfig{
 	},
 	SmtpTls: model.AppConfigVariable{
 		Key:          "smtpTls",
-		Type:         "bool",
-		DefaultValue: "true",
+		Type:         "string",
+		DefaultValue: "none",
 	},
 	SmtpSkipCertVerify: model.AppConfigVariable{
 		Key:          "smtpSkipCertVerify",

backend/internal/service/email_service.go

@@ -115,18 +115,22 @@ func (srv *EmailService) getSmtpClient() (client *smtp.Client, err error) {
 	}
 
 	// Connect to the SMTP server
-	if srv.appConfigService.DbConfig.SmtpTls.Value == "false" {
+	// Connect to the SMTP server based on TLS setting
+	switch srv.appConfigService.DbConfig.SmtpTls.Value {
+	case "none":
 		client, err = srv.connectToSmtpServer(smtpAddress)
-	} else if port == "465" {
+	case "tls":
 		client, err = srv.connectToSmtpServerUsingImplicitTLS(
 			smtpAddress,
 			tlsConfig,
 		)
-	} else {
+	case "starttls":
 		client, err = srv.connectToSmtpServerUsingStartTLS(
 			smtpAddress,
 			tlsConfig,
 		)
+	default:
+		return nil, fmt.Errorf("invalid SMTP TLS setting: %s", srv.appConfigService.DbConfig.SmtpTls.Value)
 	}
 	if err != nil {
 		return nil, fmt.Errorf("failed to connect to SMTP server: %w", err)