smtpd/envelope.go

package smtpd

import (
	"io"
	"net/mail"
	"strings"

	baseSmtpd "github.com/bradfitz/go-smtpd/smtpd"
	"github.com/go-xweb/log"
)

type DemoEnvelope struct {
	SmtpNetwork string                `json:"-"`
	SmtpRemote  string                `json:"-"`
	MailFrom    baseSmtpd.MailAddress `json:"mail_from"`
	RcptTo      baseSmtpd.MailAddress `json:"rcpt_to"`
	Lines       strings.Builder       `json:"lines"`
}

func (d *DemoEnvelope) AddRecipient(rcpt baseSmtpd.MailAddress) error {
	log.Printf("Inbound email from %s for %s", d.MailFrom.Email(), rcpt)
	d.RcptTo = rcpt
	return nil
}

func (d *DemoEnvelope) BeginData() error {
	d.Lines = strings.Builder{}
	return nil
}

func (d *DemoEnvelope) Write(line []byte) error {
	d.Lines.Write(line)
	return nil
}

func (d *DemoEnvelope) Close() error {
	msg, err := d.Parse()
	if err == nil {
		d.Handle(*msg)
	}
	return nil
}

func (d DemoEnvelope) Handle(message mail.Message) {
	//for i, h := range message.Header {
	//	first := h[0]
	//	if len(h[1:]) > 0 {
	//		log.Printf("%-10s %s(+more)\n", i, first)
	//	} else {
	//		log.Printf("%-10s %s\n", i, first)
	//	}
	//}
	parser := mail.AddressParser{}

	from, err := parser.Parse(message.Header.Get("From"))
	if err != nil {
		log.Errorf("Error parsing From: header: %v\n", err)
		from = &mail.Address{}
	}
	if from.Name == "" {
		from.Name = "(no From name)"
	}

	to, err := parser.Parse(message.Header.Get("To"))
	if err != nil {
		log.Errorf("Error parsing To: header: %v\n", err)
		to = &mail.Address{}
	}
	if to.Name == "" {
		to.Name = "(no To name)"
	}

	subject := message.Header.Get("Subject")
	body, err := io.ReadAll(message.Body)
	if err != nil {
		log.Errorf("Error reading body: %v", err)
	}
	log.Printf("From:    %-20s (%s)\n", from.Name, from.Address)
	log.Printf("To:      %-20s (%s)\n", to.Name, to.Address)
	log.Printf("Subject: %s\n", subject)
	log.Printf("Message:\n%s\n", string(body))
}

func (d DemoEnvelope) Parse() (*mail.Message, error) {
	reader := strings.NewReader(d.Lines.String())
	message, err := mail.ReadMessage(reader)
	if err != nil {
		log.Errorf("Error reading submitted message: %v", err)
		return &mail.Message{}, err
	}
	return message, nil
}