golang golang net / smtp SMTP AUTH LOGIN Auth Handler

Posted 2021-05-24

/////////////////////////////////////////////////////////////////////
// MIT license (c) jetz 2016
//
// 具体参考：http://being23.github.io/2015/09/17/使用golang发送邮件
//
// 报错504 5.7.4 Unrecognized authentication type。这是由于我司的邮
// 件服务支持LOGIN认证方式，不支持go提供的认证方式 (CRAMMD5和PLAIN)。
/////////////////////////////////////////////////////////////////////
package main

import (
	"errors"
	"net/smtp"
)

type loginAuth struct {
	username, password string
}

func LoginAuth(username, password string) smtp.Auth {
	return &loginAuth{username, password}
}

func (a *loginAuth) Start(server *smtp.ServerInfo) (string, []byte, error) {
	return "LOGIN", []byte{}, nil
}

func (a *loginAuth) Next(fromServer []byte, more bool) ([]byte, error) {
	if more {
		switch string(fromServer) {
		case "Username:":
			return []byte(a.username), nil
		case "Password:":
			return []byte(a.password), nil
		default:
			return nil, errors.New("Unkown fromServer")
		}
	}
	return nil, nil
}

// usage:
// auth := LoginAuth("loginname", "password")
// err := smtp.SendMail(smtpServer + ":25", auth, fromAddress, toAddresses, []byte(message))
// or
// client, err := smtp.Dial(smtpServer)
// client.Auth(LoginAuth("loginname", "password"))

golang 使用Go（Golang）通过GMail发送电子邮件与net / smtp

package main

import (
	"log"
	"net/smtp"
)

func main() {
	send("hello there")
}

func send(body string) {
	from := "[e-mail]"
	pass := "..."
	to := "[e-mail]"

	msg := "From: " + from + "\n" +
		"To: " + to + "\n" +
		"Subject: Hello there\n\n" +
		body

	err := smtp.SendMail("smtp.gmail.com:587",
		smtp.PlainAuth("", from, pass, "smtp.gmail.com"),
		from, []string{to}, []byte(msg))

	if err != nil {
		log.Printf("smtp error: %s", err)
		return
	}
	
	log.Print("sent, visit http://foobarbazz.mailinator.com")
}