阿里云邮件推送服务

阿里云邮件推送服务

定义

在邮箱注册，邮箱验证或者邮箱发送通知的时候，就需要用到邮箱推送服务来实现。邮箱推送除了各个平台的sdk之外，基于stmp协议的写法更加的灵活

Golang
// 邮箱信息
type SendMail struct {
	User     string // 发件人 “xxx.@163.com”
	Password string // smtp的密码
	Host     string // smtpdm.aliyun.com 使用了阿里云的服务
	Port     string // 80
	SmtpAuth smtp.Auth
}

// 附件
type Attachment struct {
	Name        string // 附件名
	FileUrl     string // 附件地址
	ContentType string // text/html;charset=utf-8
	WithFile    bool // true
}

// 邮件信息
type Message struct {
	From        string // 发件人名
	FromAlias   string // 发件人别名
	To          []string // 收件人邮箱列表
	Cc          []string //
	Bcc         []string
	Subject     string // 邮件标题
	Body        string // 邮件内容
	ReplyTo     string // 回件地址
	ContentType string // text/html;charset=utf-8 （body为html格式）
	Attachments []Attachment // 附件
	TagName     string // aliyun邮件追踪，通过tagName统计邮件数据
}


func (mail *SendMail) Auth() {
	mail.SmtpAuth = LoginAuth(mail.User, mail.Password)
}

func (mail SendMail) Send(message Message) error {
	mail.Auth()
	buffer := bytes.NewBuffer(nil)
	boundary := "GoBoundary"
	Header := make(map[string]string)
	Header["From"] = fmt.Sprintf("(%s)<%s>", message.FromAlias, message.From)
	Header["To"] = strings.Join(message.To, ";")
	Header["Cc"] = strings.Join(message.Cc, ";")
	Header["Bcc"] = strings.Join(message.Bcc, ";")
	Header["Subject"] = mime.BEncoding.Encode("UTF-8", message.Subject)
	Header["Reply-To"] = message.ReplyTo
	Header["Content-Type"] = "multipart/mixed;boundary=" + boundary
	Header["Mime-Version"] = "1.0"
	Header["Date"] = time.Now().String()

	trace := make(map[string]string)
	trace["OpenTrace"] = "1"
	trace["LinkTrace"] = "1"
	trace["TagName"] = message.TagName
	traceString, err := utils.JSONMarshal(trace)
	if err != nil {
		return err
	}
	Header["X-AliDM-Trace"] = base64.StdEncoding.EncodeToString(traceString)

	mail.writeHeader(buffer, Header)
	body := "\r\n--" + boundary + "\r\n"
	body += "Content-Type:" + message.ContentType + "\r\n"
	body += "\r\n" + message.Body + "\r\n"
	buffer.WriteString(body)

	if len(message.Attachments) > 0 {
		attachment := "\r\n--" + boundary + "\r\n"
		attachment += "Content-Transfer-Encoding:base64\r\n"
		attachment += "Content-Disposition:attachment\r\n"

		for _, messageAttachment := range message.Attachments {
			if messageAttachment.WithFile {
				attachment += "Content-Type:" + messageAttachment.ContentType + ";name=\"" + mime.BEncoding.Encode("UTF-8", messageAttachment.Name) + "\"\r\n"
				buffer.WriteString(attachment)
				defer func() {
					if err := recover(); err != nil {
						log.Fatalln(err)
					}
				}()
				err := mail.writeFile(buffer, messageAttachment.FileUrl)
				if err != nil {
					return err
				}
			}
		}
	}

	to_address := MergeSlice(message.To, message.Cc)
	to_address = MergeSlice(to_address, message.Bcc)

	buffer.WriteString("\r\n--" + boundary + "--")
	err = smtp.SendMail(mail.Host+":"+mail.Port, mail.SmtpAuth, message.From, to_address, buffer.Bytes())
	return err
}

func MergeSlice(s1 []string, s2 []string) []string {
	slice := make([]string, len(s1)+len(s2))
	copy(slice, s1)
	copy(slice[len(s1):], s2)
	return slice
}

func (mail SendMail) writeHeader(buffer *bytes.Buffer, Header map[string]string) string {
	header := ""
	for key, value := range Header {
		header += key + ":" + value + "\r\n"
	}
	header += "\r\n"
	buffer.WriteString(header)
	return header
}

// read and write the file to buffer
func (mail SendMail) writeFile(buffer *bytes.Buffer, fileUrl string) error {
	filePath := fmt.Sprintf("/tmp/files/%s", utils.MD5(fileUrl)+utils.UUID())

	defer os.Remove(filePath)

	err := utils.DownloadFile(filePath, fileUrl)
	if err != nil {
		return err
	}

	file, err := ioutil.ReadFile(filePath)
	if err != nil {
		panic(err.Error())
	}

	payload := make([]byte, base64.StdEncoding.EncodedLen(len(file)))
	base64.StdEncoding.Encode(payload, file)
	buffer.WriteString("\r\n")
	for index, line := 0, len(payload); index < line; index++ {
		buffer.WriteByte(payload[index])
		if (index+1)%76 == 0 {
			buffer.WriteString("\r\n")
		}
	}
	return nil
}

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(a.username), 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
		}
	}
	return nil, nil
}

调用

var mail smtpMail.Mail
mail = &smtpMail.SendMail{User: EMAIL_USER, Password: EMAIL_SMTP_PWD, Host: EMAIL_HOST, Port: EMAIL_PORT}

var attachments []smtpMail.Attachment
attachments = append(attachments, smtp_mail.Attachment{
	Name:        "附件名",
	FileUrl:     "xxx附件地址",
	WithFile:    true,
	ContentType: "text/html;charset=utf-8",
})

message := smtp_mail.Message{
	From:        EMAIL_USER,
	FromAlias:   EMAIL_USER_ALIAS,
	ReplyTo:     strategy.ReplyTo,
	To:          []string{author.Email},
	Subject:     subject,
	Body:        body,
	ContentType: "text/html;charset=utf-8",
	Attachments: attachments,
	TagName:     getEmailSendStrategyTagName(strategy.ID),
}

err = mail.Send(message)