fix: smtp hello for tls connections (#180)

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

backend/internal/service/email_service.go

@@ -4,10 +4,6 @@ import (
 	"bytes"
 	"crypto/tls"
 	"fmt"
-	"github.com/stonith404/pocket-id/backend/internal/common"
-	"github.com/stonith404/pocket-id/backend/internal/model"
-	"github.com/stonith404/pocket-id/backend/internal/utils/email"
-	"gorm.io/gorm"
 	htemplate "html/template"
 	"mime/multipart"
 	"mime/quotedprintable"
@@ -17,6 +13,11 @@ import (
 	"os"
 	ttemplate "text/template"
 	"time"
+
+	"github.com/stonith404/pocket-id/backend/internal/common"
+	"github.com/stonith404/pocket-id/backend/internal/model"
+	"github.com/stonith404/pocket-id/backend/internal/utils/email"
+	"gorm.io/gorm"
 )
 
 var netDialer = &net.Dialer{
@@ -89,16 +90,31 @@ func SendEmail[V any](srv *EmailService, toEmail email.Address, template email.T
 	)
 	c.Body(body)
 
-	// Set up the TLS configuration
+	// Connect to the SMTP server
+	client, err := srv.getSmtpClient()
+	if err != nil {
+		return fmt.Errorf("failed to connect to SMTP server: %w", err)
+	}
+	defer client.Close()
+
+	// Send the email
+	if err := srv.sendEmailContent(client, toEmail, c); err != nil {
+		return fmt.Errorf("send email content: %w", err)
+	}
+
+	return nil
+}
+
+func (srv *EmailService) getSmtpClient() (client *smtp.Client, err error) {
+	port := srv.appConfigService.DbConfig.SmtpPort.Value
+	smtpAddress := srv.appConfigService.DbConfig.SmtpHost.Value + ":" + port
+
 	tlsConfig := &tls.Config{
 		InsecureSkipVerify: srv.appConfigService.DbConfig.SmtpSkipCertVerify.Value == "true",
 		ServerName:         srv.appConfigService.DbConfig.SmtpHost.Value,
 	}
 
 	// Connect to the SMTP server
-	port := srv.appConfigService.DbConfig.SmtpPort.Value
-	smtpAddress := srv.appConfigService.DbConfig.SmtpHost.Value + ":" + port
-	var client *smtp.Client
 	if srv.appConfigService.DbConfig.SmtpTls.Value == "false" {
 		client, err = srv.connectToSmtpServer(smtpAddress)
 	} else if port == "465" {
@@ -112,24 +128,14 @@ func SendEmail[V any](srv *EmailService, toEmail email.Address, template email.T
 			tlsConfig,
 		)
 	}
-
 	if err != nil {
-		return fmt.Errorf("failed to connect to SMTP server: %w", err)
-	}
-	defer client.Close()
-
-	// Set the hello message manually as for example Google rejects the default "localhost" value
-	hostname, err := os.Hostname()
-	if err == nil {
-		if err := client.Hello(hostname); err != nil {
-			return fmt.Errorf("failed to say hello to SMTP server: %w", err)
-		}
+		return nil, fmt.Errorf("failed to connect to SMTP server: %w", err)
 	}
 
+	// Set up the authentication if user or password are set
 	smtpUser := srv.appConfigService.DbConfig.SmtpUser.Value
 	smtpPassword := srv.appConfigService.DbConfig.SmtpPassword.Value
 
-	// Set up the authentication if user or password are set
 	if smtpUser != "" || smtpPassword != "" {
 		auth := smtp.PlainAuth("",
 			srv.appConfigService.DbConfig.SmtpUser.Value,
@@ -137,16 +143,11 @@ func SendEmail[V any](srv *EmailService, toEmail email.Address, template email.T
 			srv.appConfigService.DbConfig.SmtpHost.Value,
 		)
 		if err := client.Auth(auth); err != nil {
-			return fmt.Errorf("failed to authenticate SMTP client: %w", err)
+			return nil, fmt.Errorf("failed to authenticate SMTP client: %w", err)
 		}
 	}
 
-	// Send the email
-	if err := srv.sendEmailContent(client, toEmail, c); err != nil {
-		return fmt.Errorf("send email content: %w", err)
-	}
-
-	return nil
+	return client, err
 }
 
 func (srv *EmailService) connectToSmtpServer(serverAddr string) (*smtp.Client, error) {
@@ -155,6 +156,15 @@ func (srv *EmailService) connectToSmtpServer(serverAddr string) (*smtp.Client, e
 		return nil, fmt.Errorf("failed to connect to SMTP server: %w", err)
 	}
 	client, err := smtp.NewClient(conn, srv.appConfigService.DbConfig.SmtpHost.Value)
+	if err != nil {
+		conn.Close()
+		return nil, fmt.Errorf("failed to create SMTP client: %w", err)
+	}
+
+	if err := srv.sendHelloCommand(client); err != nil {
+		return nil, fmt.Errorf("failed to say hello to SMTP server: %w", err)
+	}
+
 	return client, err
 }
 
@@ -174,6 +184,10 @@ func (srv *EmailService) connectToSmtpServerUsingImplicitTLS(serverAddr string,
 		return nil, fmt.Errorf("failed to create SMTP client: %w", err)
 	}
 
+	if err := srv.sendHelloCommand(client); err != nil {
+		return nil, fmt.Errorf("failed to say hello to SMTP server: %w", err)
+	}
+
 	return client, nil
 }
 
@@ -189,12 +203,26 @@ func (srv *EmailService) connectToSmtpServerUsingStartTLS(serverAddr string, tls
 		return nil, fmt.Errorf("failed to create SMTP client: %w", err)
 	}
 
+	if err := srv.sendHelloCommand(client); err != nil {
+		return nil, fmt.Errorf("failed to say hello to SMTP server: %w", err)
+	}
+
 	if err := client.StartTLS(tlsConfig); err != nil {
 		return nil, fmt.Errorf("failed to start TLS: %w", err)
 	}
 	return client, nil
 }
 
+func (srv *EmailService) sendHelloCommand(client *smtp.Client) error {
+	hostname, err := os.Hostname()
+	if err == nil {
+		if err := client.Hello(hostname); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 func (srv *EmailService) sendEmailContent(client *smtp.Client, toEmail email.Address, c *email.Composer) error {
 	if err := client.Mail(srv.appConfigService.DbConfig.SmtpFrom.Value); err != nil {
 		return fmt.Errorf("failed to set sender: %w", err)

frontend/src/routes/settings/admin/application-configuration/forms/app-config-email-form.svelte

@@ -77,7 +77,7 @@
 		isSendingTestEmail = true;
 		await appConfigService
 			.sendTestEmail()
-			.then(() => toast.success('Test email sent successfully to your Email address.'))
+			.then(() => toast.success('Test email sent successfully to your email address.'))
 			.catch(() =>
 				toast.error('Failed to send test email. Check the server logs for more information.')
 			)