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package smtp_test
import (
"errors"
"io"
"log"
"time"
"github.com/emersion/go-sasl"
"github.com/emersion/go-smtp"
)
// The Backend implements SMTP server methods.
type Backend struct{}
// NewSession is called after client greeting (EHLO, HELO).
func (bkd *Backend) NewSession(c *smtp.Conn) (smtp.Session, error) {
return &Session{}, nil
}
// A Session is returned after successful login.
type Session struct{}
// AuthMechanisms returns a slice of available auth mechanisms; only PLAIN is
// supported in this example.
func (s *Session) AuthMechanisms() []string {
return []string{sasl.Plain}
}
// Auth is the handler for supported authenticators.
func (s *Session) Auth(mech string) (sasl.Server, error) {
return sasl.NewPlainServer(func(identity, username, password string) error {
if username != "username" || password != "password" {
return errors.New("Invalid username or password")
}
return nil
}), nil
}
func (s *Session) Mail(from string, opts *smtp.MailOptions) error {
log.Println("Mail from:", from)
return nil
}
func (s *Session) Rcpt(to string, opts *smtp.RcptOptions) error {
log.Println("Rcpt to:", to)
return nil
}
func (s *Session) Data(r io.Reader) error {
if b, err := io.ReadAll(r); err != nil {
return err
} else {
log.Println("Data:", string(b))
}
return nil
}
func (s *Session) Reset() {}
func (s *Session) Logout() error {
return nil
}
// ExampleServer runs an example SMTP server.
//
// It can be tested manually with e.g. netcat:
//
// > netcat -C localhost 1025
// EHLO localhost
// AUTH PLAIN
// AHVzZXJuYW1lAHBhc3N3b3Jk
// MAIL FROM:<root@nsa.gov>
// RCPT TO:<root@gchq.gov.uk>
// DATA
// Hey <3
// .
func ExampleServer() {
be := &Backend{}
s := smtp.NewServer(be)
s.Addr = "localhost:1025"
s.Domain = "localhost"
s.WriteTimeout = 10 * time.Second
s.ReadTimeout = 10 * time.Second
s.MaxMessageBytes = 1024 * 1024
s.MaxRecipients = 50
s.AllowInsecureAuth = true
log.Println("Starting server at", s.Addr)
if err := s.ListenAndServe(); err != nil {
log.Fatal(err)
}
}
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