opt: smtp rfc

utils/smtp/format.go

@@ -1,25 +1,92 @@
 package smtp
 
 import (
+	"bytes"
 	"encoding/base64"
 	"fmt"
+	"mime"
 	"strings"
+	"time"
 
 	smtp "github.com/emersion/go-smtp"
 	"github.com/zijiren233/stream"
 )
 
-func FormatMail(from string, to []string, subject string, body any) string {
-	return fmt.Sprintf(
-		"From: %s\r\nTo: %s\r\nSubject: =?UTF-8?B?%s?=\r\nContent-Type: text/html; charset=UTF-8\r\n\r\n%v",
-		from,
-		strings.Join(to, ","),
-		base64.StdEncoding.EncodeToString(stream.StringToBytes(subject)),
-		body,
-	)
+type FormatMailConfig struct {
+	date                    string
+	mimeVersion             string
+	contentType             string
+	contentTransferEncoding string
+}
+
+type FormatMailOption func(c *FormatMailConfig)
+
+func WithDate(date time.Time) FormatMailOption {
+	return func(c *FormatMailConfig) {
+		c.date = date.Format(time.RFC1123Z)
+	}
+}
+
+func WithMimeVersion(mimeVersion string) FormatMailOption {
+	return func(c *FormatMailConfig) {
+		c.mimeVersion = mimeVersion
+	}
+}
+
+func WithContentType(contentType string) FormatMailOption {
+	return func(c *FormatMailConfig) {
+		c.contentType = contentType
+	}
+}
+
+func WithContentTransferEncoding(contentTransferEncoding string) FormatMailOption {
+	return func(c *FormatMailConfig) {
+		c.contentTransferEncoding = contentTransferEncoding
+	}
+}
+
+func FormatMail(from string, to []string, subject string, body string, opts ...FormatMailOption) string {
+	c := &FormatMailConfig{
+		date:                    time.Now().Format(time.RFC1123Z),
+		mimeVersion:             "1.0",
+		contentType:             "text/html; charset=UTF-8",
+		contentTransferEncoding: "base64",
+	}
+	for _, opt := range opts {
+		opt(c)
+	}
+	buf := bytes.NewBuffer(nil)
+
+	buf.WriteString(fmt.Sprintf("From: %s\r\n", from))
+	buf.WriteString(fmt.Sprintf("To: %s\r\n", strings.Join(to, ", ")))
+	buf.WriteString(fmt.Sprintf("Subject: %s\r\n", mime.QEncoding.Encode("UTF-8", subject)))
+	buf.WriteString(fmt.Sprintf("Date: %s\r\n", c.date))
+	buf.WriteString(fmt.Sprintf("MIME-Version: %s\r\n", c.mimeVersion))
+	buf.WriteString(fmt.Sprintf("Content-Type: %s\r\n", c.contentType))
+	if c.contentTransferEncoding != "" {
+		buf.WriteString(fmt.Sprintf("Content-Transfer-Encoding: %s\r\n", c.contentTransferEncoding))
+	}
+
+	buf.WriteString("\r\n")
+
+	switch c.contentTransferEncoding {
+	case "base64":
+		encodedBody := base64.StdEncoding.EncodeToString(stream.StringToBytes(body))
+		for i := 0; i < len(encodedBody); i += 76 {
+			end := i + 76
+			if end > len(encodedBody) {
+				end = len(encodedBody)
+			}
+			buf.WriteString(encodedBody[i:end] + "\r\n")
+		}
+	case "":
+		buf.WriteString(body)
+	}
+
+	return buf.String()
 }
 
-func SendEmail(cli *smtp.Client, from string, to []string, subject, body string) error {
+func SendEmail(cli *smtp.Client, from string, to []string, subject, body string, opts ...FormatMailOption) error {
 	return cli.SendMail(
 		from,
 		to,
@@ -29,6 +96,7 @@ func SendEmail(cli *smtp.Client, from string, to []string, subject, body string)
 				to,
 				subject,
 				body,
+				opts...,
 			),
 		),
 	)

utils/smtp/smtpool.go

@@ -162,13 +162,13 @@ func (p *SmtpPool) Close() {
 	p.clients = nil
 }
 
-func (p *SmtpPool) SendEmail(to []string, subject, body string) error {
+func (p *SmtpPool) SendEmail(to []string, subject, body string, opts ...FormatMailOption) error {
 	cli, err := p.Get()
 	if err != nil {
 		return err
 	}
 	defer p.Put(cli)
-	return SendEmail(cli, p.c.From, to, subject, body)
+	return SendEmail(cli, p.c.From, to, subject, body, opts...)
 }
 
 func (p *SmtpPool) SetFrom(from string) {