GitHub - xhit/go-simple-mail: Golang package for send email. Support keep alive connection, TLS and SSL. Easy for bulk SMTP. (original) (raw)

Go Simple Mail

The best way to send emails in Go with SMTP Keep Alive and Timeout for Connect and Send.

Go Report Card go.dev

IMPORTANT

Examples in this README are for v2.2.0 and above. Examples for older versions can be found here.

Go 1.13+ is required.

Breaking change in 2.2.0: The signature of SetBody and AddAlternative used to accept strings ("text/html" and "text/plain") and not require on of thecontentType constants (TextHTML or TextPlain). Upgrading, while not quite following semantic versioning, is quite simple:

email := mail.NewMSG()

Introduction

Go Simple Mail is a simple and efficient package to send emails. It is well tested and documented.

Go Simple Mail can only send emails using an SMTP server. But the API is flexible and it is easy to implement other methods for sending emails using a local Postfix, an API, etc.

This package contains (and is based on) two packages by Joe Grasse:

A lot of changes in Go Simple Mail were sent with not response.

Features

Go Simple Mail supports:

Documentation

https://pkg.go.dev/github.com/xhit/go-simple-mail/v2?tab=doc

Note 1: by default duplicated recipients throws an error, from v2.13.0 you can use email.AllowDuplicateAddress = true to avoid the check.

Note 2: by default Bcc header is not set in email. From v2.14.0 you can use email.AddBccToHeader = true to add this.

Note 3: by default all addresses are validated against RFC5322. Setting email.UseProvidedAddress = true skips this validation, but requires you to ensure a valid address is sent.

Download

This package uses go modules.

$ go get github.com/xhit/go-simple-mail/v2

Usage

package main

import ( "log"

mail "github.com/xhit/go-simple-mail/v2"
"github.com/toorop/go-dkim"

)

const htmlBody = ` Hello Gophers!

This is the Go gopher.

Go gopher

Image created by Renee French

`

const privateKey = -----BEGIN RSA PRIVATE KEY----- MIIEpAIBAAKCAQEAwGrscUxi9zEa9oMOJbS0kLVHZXNIW+EBjY7KFWIZSxuGAils wBVl+s5mMRrR5VlkyLQNulAdNemg6OSeB0R+2+8/lkHiMrimqQckZ5ig8slBoZhZ wUoL/ZkeQa1bacbdww5TuWkiVPD9kooT/+TZW1P/ugd6oYjpOI56ZjsXzJw5pz7r DiwcIJJaaDIqvvc5C4iW94GZjwtmP5pxhvBZ5D6Uzmh7Okvi6z4QCKzdJQLdVmC0 CMiFeh2FwqMkVpjZhNt3vtCo7Z51kwHVscel6vl51iQFq/laEzgzAWOUQ+ZEoQpL uTaUiYzzNyEdGEzZ2CjMMoO8RgtXnUo2qX2FDQIDAQABAoIBAHWKW3kycloSMyhX EnNSGeMz+bMtYwxNPMeebC/3xv+shoYXjAkiiTNWlfJ1MbbqjrhT1Pb1LYLbfqIF 1csWum/bjHpbMLRPO++RH1nxUJA/BMqT6HA8rWpy+JqiLW9GPf2DaP2gDYrZ0+yK UIFG6MfzXgnju7OlkOItlvOQMY+Y501u/h6xnN2yTeRqXXJ1YlWFPRIeFdS6UOtL J2wSxRVdymHbGwf+D7zet7ngMPwFBsbEN/83KGLRjkt8+dMQeUeob+nslsQofCZx iokIAvByTugmqrB4JqhNkAlZhC0mqkRQh7zUFrxSj5UppMWlxLH+gPFZHKAsUJE5 mqmylcECgYEA8I/f90cpF10uH4NPBCR4+eXq1PzYoD+NdXykN65bJTEDZVEy8rBO phXRNfw030sc3R0waQaZVhFuSgshhRuryfG9c1FP6tQhqi/jiEj9IfCW7zN9V/P2 r16pGjLuCK4SyxUC8H58Q9I0X2CQqFamtkLXC6Ogy86rZfIc8GcvZ9UCgYEAzMQZ WAiLhRF2MEmMhKL+G3jm20r+dOzPYkfGxhIryluOXhuUhnxZWL8UZfiEqP5zH7Li NeJvLz4pOL45rLw44qiNu6sHN0JNaKYvwNch1wPT/3/eDNZKKePqbAG4iamhjLy5 gjO1KgA5FBbcNN3R6fuJAg1e4QJCOuo55eW6vFkCgYEA7UBIV72D5joM8iFzvZcn BPdfqh2QnELxhaye3ReFZuG3AqaZg8akWqLryb1qe8q9tclC5GIQulTInBfsQDXx MGLNQL0x/1ylsw417kRl+qIoidMTTLocUgse5erS3haoDEg1tPBaKB1Zb7NyF8QV +W1kX2NKg5bZbdrh9asekt0CgYA6tUam7NxDrLv8IDo/lRPSAJn/6cKG95aGERo2 k+MmQ5XP+Yxd+q0LOs24ZsZyRXHwdrNQy7khDGt5L2EN23Fb2wO3+NM6zrGu/WbX nVbAdQKFUL3zZEUjOYtuqBemsJH27e0qHXUls6ap0dwU9DxJH6sqgXbggGtIxPsQ pQsjEQKBgQC9gAqAj+ZtMXNG9exVPT8I15reox9kwxGuvJrRu/5eSi6jLR9z3x9P 2FrgxQ+GCB2ypoOUcliXrKesdSbolUilA8XQn/M113Lg8oA3gJXbAKqbTR/EgfUU kvYaR/rTFnivF4SL/P4k/gABQoJuFUtSKdouELqefXB+e94g/G++Bg== -----END RSA PRIVATE KEY-----

func main() { server := mail.NewSMTPClient()

// SMTP Server
server.Host = "smtp.example.com"
server.Port = 587
server.Username = "test@example.com"
server.Password = "examplepass"
server.Encryption = mail.EncryptionSTARTTLS

// You can specified authentication type:
// - AUTO (default)
// - PLAIN
// - LOGIN
// - CRAM-MD5
// - None
// server.Authentication = mail.AuthAuto

// Variable to keep alive connection
server.KeepAlive = false

// Timeout for connect to SMTP Server
server.ConnectTimeout = 10 * time.Second

// Timeout for send the data and wait respond
server.SendTimeout = 10 * time.Second

// Set TLSConfig to provide custom TLS configuration. For example,
// to skip TLS verification (useful for testing):
server.TLSConfig = &tls.Config{InsecureSkipVerify: true}

// SMTP client
smtpClient,err := server.Connect()

if err != nil{
    log.Fatal(err)
}

// New email simple html with inline and CC
email := mail.NewMSG()
email.SetFrom("From Example <nube@example.com>").
    AddTo("xhit@example.com").
    AddCc("otherto@example.com").
    SetSubject("New Go Email").
    SetListUnsubscribe("<mailto:unsubscribe@example.com?subject=https://example.com/unsubscribe>")

email.SetBody(mail.TextHTML, htmlBody)

// also you can add body from []byte with SetBodyData, example:
// email.SetBodyData(mail.TextHTML, []byte(htmlBody))
// or alternative part
// email.AddAlternativeData(mail.TextHTML, []byte(htmlBody))

// add inline
email.Attach(&mail.File{FilePath: "/path/to/image.png", Name:"Gopher.png", Inline: true})

// also you can set Delivery Status Notification (DSN) (only is set when server supports DSN)
email.SetDSN([]mail.DSN{mail.SUCCESS, mail.FAILURE}, false)

// you can add dkim signature to the email. 
// to add dkim, you need a private key already created one.
if privateKey != "" {
    options := dkim.NewSigOptions()
    options.PrivateKey = []byte(privateKey)
    options.Domain = "example.com"
    options.Selector = "default"
    options.SignatureExpireIn = 3600
    options.Headers = []string{"from", "date", "mime-version", "received", "received"}
    options.AddSignatureTimestamp = true
    options.Canonicalization = "relaxed/relaxed"

    email.SetDkim(options)
}

// always check error before send
if email.Error != nil{
    log.Fatal(email.Error)
}

// Call Send and pass the client
err = email.Send(smtpClient)
if err != nil {
    log.Println(err)
} else {
    log.Println("Email Sent")
}

}

Send multiple emails in same connection

//Set your smtpClient struct to keep alive connection
server.KeepAlive = true

for _, to := range []string{
    "to1@example1.com",
    "to3@example2.com",
    "to4@example3.com",
} {
    // New email simple html with inline and CC
    email := mail.NewMSG()
    email.SetFrom("From Example <nube@example.com>").
        AddTo(to).
        SetSubject("New Go Email")

    email.SetBody(mail.TextHTML, htmlBody)

    // add inline
    email.Attach(&mail.File{FilePath: "/path/to/image.png", Name:"Gopher.png", Inline: true})

    // always check error before send
    if email.Error != nil{
        log.Fatal(email.Error)
    }

    // Call Send and pass the client
    err = email.Send(smtpClient)
    if err != nil {
        log.Println(err)
    } else {
        log.Println("Email Sent")
    }
}

Send with custom connection

It's possible to use a custom connection with custom dieler, like a dialer that uses a proxy server, etc...

With this, these servers params are ignored: Host, Port. You have total control of the connection.

Example using a conn for proxy:

package main

import ( "crypto/tls" "fmt" "log" "net"

mail "github.com/xhit/go-simple-mail/v2"
"golang.org/x/net/proxy"

)

func main() { server := mail.NewSMTPClient()

host := "smtp.example.com"
port := 587
proxyAddr := "proxy.server"

conn, err := getCustomConnWithProxy(proxyAddr, host, port)
if err != nil {
    log.Fatal(err)
}

server.Username = "test@example.com"
server.Password = "examplepass"
server.Encryption = mail.EncryptionSTARTTLS
server.CustomConn = conn

smtpClient, err := server.Connect()
if err != nil {
    log.Fatal(err)
}

email := mail.NewMSG()

err = email.SetFrom("From Example <nube@example.com>").AddTo("xhit@example.com").Send(smtpClient)
if err != nil {
    log.Fatal(err)
}

}

func getCustomConnWithProxy(proxyAddr, host string, port int) (net.Conn, error) { dial, err := proxy.SOCKS5("tcp", proxyAddr, nil, proxy.Direct) if err != nil { return nil, err }

dialer, err := dial.Dial("tcp", fmt.Sprintf("%s:%d", host, port))
if err != nil {
    return nil, err
}

conf := &tls.Config{ServerName: host}
conn := tls.Client(dialer, conf)

return conn, nil

}

More examples

See example/example_test.go.