smtpd

README

lavab/smtpd

smtpd is a simple library for implementing SMTP servers in Golang. Supports STARTTLS, middleware chains for event handling and configurable limits, proxy protocol for servers listening behind HAProxy of Amazon ELB load balancers.

Example

package main

import (
	"log"

	"github.com/getsentry/raven-go"
	"github.com/lavab/smtpd"
)

func main() {
	// Connect to raven for sentry logging
	rc, err := raven.NewClient("some raven dsn", nil)
	if err != nil {
		log.Fatal(err)
	}

	// Create a new SMTPD server
	server := &smtpd.Server{
		WelcomeMessage: "Hello world!",

		WrapperChain: []smtpd.Wrapper{
			smtpd.Wrapper(func(next smtpd.Wrapped) smtpd.Wrapped {
				return smtpd.Wrapped(func() {
					rc.CapturePanic(next, nil)
				})
			}),
		},
		DeliveryChain: []smtpd.Middleware{
			smtpd.Middleware(func(next smtpd.Handler) smtpd.Handler {
				return smtpd.Handler(func(conn *smtpd.Connection) {
					log.Printf("Sender: %s", conn.Envelope.Sender)
					log.Printf("Recipients: %s", strings.Join(conn.Envelope.Recipients, ", "))
					log.Printf("Body:\n%s", string(conn.Envelope.Body))
					
					next(conn)
				})
			}),
		},
	}

	// Bind it to an address
	if err := server.ListenAndServe(":25"); err != nil {
		log.Fatal(err)
	}
}

Documentation

Index

• Constants
• Variables
• func StatusString(status int) string
• type Connection
  • func (c *Connection) Error(err error)
• type Envelope
  • func (e *Envelope) AddReceivedLine(c *Connection)
• type Error
  • func (e Error) Error() string
• type Handler
• type Protocol
  • func (p Protocol) String() string
• type Server
  • func (s *Server) ListenAndServe(addr string) error
  • func (s *Server) Serve(l net.Listener) error

Constants

const (
	StatusPasswordNeeded       = 432
	StatusMessageError         = 450
	StatusMessageExceedStorage = 452
	StatusTempAuthFailure      = 454
	StatusAuthInvalid          = 535
	StatusAuthRequired         = 530
	StatusEncryptionRequired   = 538
	StatusServerError          = 550
	StatusExceedStorage        = 552
)

Variables

var (
	ErrPasswordNeeded       = Error{Code: StatusPasswordNeeded, Message: StatusString(StatusPasswordNeeded)}
	ErrMessageError         = Error{Code: StatusMessageError, Message: StatusString(StatusMessageError)}
	ErrMessageExceedStorage = Error{Code: StatusMessageExceedStorage, Message: StatusString(StatusMessageExceedStorage)}
	ErrTempAuthFailure      = Error{Code: StatusTempAuthFailure, Message: StatusString(StatusTempAuthFailure)}
	ErrAuthInvalid          = Error{Code: StatusAuthInvalid, Message: StatusString(StatusAuthInvalid)}
	ErrAuthRequired         = Error{Code: StatusAuthRequired, Message: StatusString(StatusAuthRequired)}
	ErrServerError          = Error{Code: StatusServerError, Message: StatusString(StatusServerError)}
	ErrExceedStorage        = Error{Code: StatusExceedStorage, Message: StatusString(StatusExceedStorage)}
)

Functions

func StatusString

func StatusString(status int) string

Types

type Connection

type Connection struct {
	Server *Server

	HeloName string
	Protocol Protocol
	Addr     net.Addr
	TLS      *tls.ConnectionState

	Envelope    *Envelope
	Environment map[string]interface{}
	// contains filtered or unexported fields
}

func (*Connection) Error

func (c *Connection) Error(err error)

type Envelope

type Envelope struct {
	Sender     string
	Recipients []string
	Data       []byte
}

func (*Envelope) AddReceivedLine

func (e *Envelope) AddReceivedLine(c *Connection)

type Error

type Error struct {
	Code    int
	Message string
}

func (Error) Error

func (e Error) Error() string

type Handler

type Handler func(conn *Connection) error

type Protocol

type Protocol string

const (
	SMTP  Protocol = "SMTP"
	ESMTP          = "ESMTP"
)

func (Protocol) String

func (p Protocol) String() string

type Server

type Server struct {
	Hostname       string
	WelcomeMessage string

	ReadTimeout  time.Duration
	WriteTimeout time.Duration
	DataTimeout  time.Duration

	MaxConnections int
	MaxMessageSize int
	MaxRecipients  int

	// WrapperChain   []Wrapper
	// SenderChain    []Sender
	// RecipientChain []Recipient
	// DeliveryChain  []Delivery
	OnConnection Handler
	OnStartTLS   Handler
	OnMail       Handler

	TLSConfig     *tls.Config
	ForceTLS      bool
	ProxyProtocol bool
	// contains filtered or unexported fields
}

func (*Server) ListenAndServe

func (s *Server) ListenAndServe(addr string) error

func (*Server) Serve

func (s *Server) Serve(l net.Listener) error