Sending Mail

See also:

• net/smtp
• Email packages

Streaming the body:

package main

import (
	"bytes"
	"log"
	"net/smtp"
)

func main() {
	// Connect to the remote SMTP server.
	c, err := smtp.Dial("mail.example.com:25")
	if err != nil {
		log.Fatal(err)
	}
	defer c.Close()
	// Set the sender and recipient.
	c.Mail("sender@example.org")
	c.Rcpt("recipient@example.net")
	// Send the email body.
	wc, err := c.Data()
	if err != nil {
		log.Fatal(err)
	}
	defer wc.Close()
	buf := bytes.NewBufferString("This is the email body.")
	if _, err = buf.WriteTo(wc); err != nil {
		log.Fatal(err)
	}
}

Authenticated SMTP:

package main

import (
	"log"
	"net/smtp"
)

func main() {
	// Set up authentication information.
	auth := smtp.PlainAuth(
		"",
		"user@example.com",
		"password",
		"mail.example.com",
	)
	// Connect to the server, authenticate, set the sender and recipient,
	// and send the email all in one step.
	err := smtp.SendMail(
		"mail.example.com:25",
		auth,
		"sender@example.org",
		[]string{"recipient@example.net"},
		[]byte("This is the email body."),
	)
	if err != nil {
		log.Fatal(err)
	}
}