gomail/send.go

138 lines
2.7 KiB
Go

package gomail
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"net/mail"
"strings"
)
// Sender is the interface that wraps the Send method.
//
// Send sends an email to the given addresses.
type Sender interface {
Send(from string, to []string, msg io.Reader) error
}
// SendCloser is the interface that groups the Send and Close methods.
type SendCloser interface {
Sender
Close() error
}
// A SendFunc is a function that sends emails to the given adresses.
// The SendFunc type is an adapter to allow the use of ordinary functions as
// email senders. If f is a function with the appropriate signature, SendFunc(f)
// is a Sender object that calls f.
type SendFunc func(from string, to []string, msg io.Reader) error
// Send calls f(from, to, msg).
func (f SendFunc) Send(from string, to []string, msg io.Reader) error {
return f(from, to, msg)
}
// Send sends emails using the given Sender.
func Send(s Sender, msg ...*Message) error {
for i, m := range msg {
if err := send(s, m); err != nil {
return fmt.Errorf("gomail: could not send email %d: %v", i+1, err)
}
}
return nil
}
func send(s Sender, msg *Message) error {
message := msg.Export()
from, err := getFrom(message)
if err != nil {
return err
}
to, err := getRecipients(message)
if err != nil {
return err
}
h := flattenHeader(message)
body, err := ioutil.ReadAll(message.Body)
if err != nil {
return err
}
mail := bytes.NewReader(append(h, body...))
if err := s.Send(from, to, mail); err != nil {
return err
}
return nil
}
func flattenHeader(msg *mail.Message) []byte {
buf := getBuffer()
defer putBuffer(buf)
for field, value := range msg.Header {
if field != "Bcc" {
buf.WriteString(field)
buf.WriteString(": ")
buf.WriteString(strings.Join(value, ", "))
buf.WriteString("\r\n")
}
}
buf.WriteString("\r\n")
return buf.Bytes()
}
func getFrom(msg *mail.Message) (string, error) {
from := msg.Header.Get("Sender")
if from == "" {
from = msg.Header.Get("From")
if from == "" {
return "", errors.New("gomail: invalid message, \"From\" field is absent")
}
}
return parseAddress(from)
}
func getRecipients(msg *mail.Message) ([]string, error) {
var list []string
for _, field := range []string{"To", "Cc", "Bcc"} {
if addresses, ok := msg.Header[field]; ok {
for _, a := range addresses {
addr, err := parseAddress(a)
if err != nil {
return nil, err
}
list = addAdress(list, addr)
}
}
}
return list, nil
}
func addAdress(list []string, addr string) []string {
for _, a := range list {
if addr == a {
return list
}
}
return append(list, addr)
}
func parseAddress(field string) (string, error) {
a, err := mail.ParseAddress(field)
if a == nil {
return "", err
}
return a.Address, err
}