Merge pull request #1353 from lol2x/main

fix: encode email subject headers according to RFC 2047

Author: mattwoberts

app/services/email/awsses/awsses.go

@@ -110,7 +110,7 @@ func sendMail(ctx context.Context, c *cmd.SendMail) {
 					},
 					Subject: &ses.Content{
 						Charset: aws.String("UTF-8"),
-						Data:    aws.String(message.Subject),
+						Data:    aws.String(email.EncodeSubject(message.Subject)),
 					},
 				},
 			},

app/services/email/mailgun/sendmail.go

@@ -50,7 +50,7 @@ func sendMail(ctx context.Context, c *cmd.SendMail) {
 	form := url.Values{}
 	form.Add("from", c.From.String())
 	form.Add("h:Reply-To", c.From.Address)
-	form.Add("subject", message.Subject)
+	form.Add("subject", email.EncodeSubject(message.Subject))
 	form.Add("html", message.Body)
 	form.Add("o:tag", fmt.Sprintf("template:%s", c.TemplateName))
 

app/services/email/message.go

@@ -3,7 +3,9 @@ package email
 import (
 	"bytes"
 	"context"
+	"mime"
 	"strings"
+	"unicode"
 
 	"github.com/getfider/fider/app/models/dto"
 	"github.com/getfider/fider/app/pkg/tpl"
@@ -15,6 +17,26 @@ type Message struct {
 	Body    string
 }
 
+// EncodeSubject encodes the subject header according to RFC 2047 if it contains non-ASCII characters
+func EncodeSubject(subject string) string {
+	// Check if the subject contains non-ASCII characters
+	hasNonASCII := false
+	for _, r := range subject {
+		if r > unicode.MaxASCII {
+			hasNonASCII = true
+			break
+		}
+	}
+	
+	// If it's pure ASCII, no encoding is needed
+	if !hasNonASCII {
+		return subject
+	}
+	
+	// Use Go's built-in MIME header encoding which implements RFC 2047
+	return mime.QEncoding.Encode("utf-8", subject)
+}
+
 // RenderMessage returns the HTML of an email based on template and params
 func RenderMessage(ctx context.Context, templateName string, fromAddress string, params dto.Props) *Message {
 	noreply := false

app/services/email/message_test.go

@@ -0,0 +1,59 @@
+package email_test
+
+import (
+	"testing"
+
+	"github.com/getfider/fider/app/services/email"
+	. "github.com/getfider/fider/app/pkg/assert"
+)
+
+func TestEncodeSubject_ASCIIOnly(t *testing.T) {
+	RegisterT(t)
+	
+	subject := "Hello World"
+	encoded := email.EncodeSubject(subject)
+	
+	Expect(encoded).Equals("Hello World")
+}
+
+func TestEncodeSubject_WithNonASCII(t *testing.T) {
+	RegisterT(t)
+	
+	subject := "Test ä ö ü"
+	encoded := email.EncodeSubject(subject)
+	
+	// The encoded result should be in RFC 2047 format
+	Expect(encoded).ContainsSubstring("=?utf-8?q?")
+	Expect(encoded).ContainsSubstring("?=")
+}
+
+func TestEncodeSubject_WithEmoji(t *testing.T) {
+	RegisterT(t)
+	
+	subject := "Hello 👋 World 🌍"
+	encoded := email.EncodeSubject(subject)
+	
+	// The encoded result should be in RFC 2047 format
+	Expect(encoded).ContainsSubstring("=?utf-8?q?")
+	Expect(encoded).ContainsSubstring("?=")
+}
+
+func TestEncodeSubject_Empty(t *testing.T) {
+	RegisterT(t)
+	
+	subject := ""
+	encoded := email.EncodeSubject(subject)
+	
+	Expect(encoded).Equals("")
+}
+
+func TestEncodeSubject_WithUmlautsAndSpecialChars(t *testing.T) {
+	RegisterT(t)
+	
+	subject := "Öffentliche Ankündigung - Größere Änderungen"
+	encoded := email.EncodeSubject(subject)
+	
+	// The encoded result should be in RFC 2047 format
+	Expect(encoded).ContainsSubstring("=?utf-8?q?")
+	Expect(encoded).ContainsSubstring("?=")
+}

app/services/email/smtp/smtp.go

@@ -90,7 +90,7 @@ func sendMail(ctx context.Context, c *cmd.SendMail) {
 		b.Set("From", c.From.String())
 		b.Set("Reply-To", c.From.Address)
 		b.Set("To", to.String())
-		b.Set("Subject", message.Subject)
+		b.Set("Subject", email.EncodeSubject(message.Subject))
 		b.Set("MIME-version", "1.0")
 		b.Set("Content-Type", "text/html; charset=\"UTF-8\"")
 		b.Set("Date", time.Now().Format(time.RFC1123Z))