Email rate limiting + tests

server/mailer.go

@@ -0,0 +1,35 @@
+package server
+
+import (
+	"fmt"
+	"net"
+	"net/smtp"
+	"strings"
+)
+
+type mailer interface {
+	Send(to string, m *message) error
+}
+
+type smtpMailer struct {
+	config *Config
+}
+
+func (s *smtpMailer) Send(to string, m *message) error {
+	host, _, err := net.SplitHostPort(s.config.SMTPAddr)
+	if err != nil {
+		return err
+	}
+	subject := m.Title
+	if subject == "" {
+		subject = m.Message
+	}
+	subject += " - " + m.Topic
+	subject = strings.ReplaceAll(strings.ReplaceAll(subject, "\r", ""), "\n", " ")
+	msg := []byte(fmt.Sprintf("From: %s\r\n"+
+		"To: %s\r\n"+
+		"Subject: %s\r\n\r\n"+
+		"%s\r\n", s.config.SMTPFrom, to, subject, m.Message))
+	auth := smtp.PlainAuth("", s.config.SMTPUser, s.config.SMTPPass, host)
+	return smtp.SendMail(s.config.SMTPAddr, auth, s.config.SMTPFrom, []string{to}, msg)
+}