---

Hi! I have personal interest in getting this patch upstream because it is biting a few of my users.

This is a proof of concept Message-ID implementation, mostly for discussion.

The format is partially gleaned from https://talk.begriffs.com/pipermail/friends/2020-August/001144.html

This patch doesn't work exactly as provided, but is a rough draft of the idea - I'm sure you'd like to see
generateMessageID moved to a different place, for example, but I wasn't sure where. So, here are my questions.

todo: currently the domain isn't stripped from the from addr, but it should be trivial to do.

0. do you want have plans for this or am i stepping on toes here?
1. would you like the helper functions moved to a different place? If so, where?
2. would you prefer to encode in base70? I chose base64 because the stdlib makes it easy.

 plugins/base/smtp.go | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/plugins/base/smtp.go b/plugins/base/smtp.go
index 19c9e0b..8d0ba2b 100644
--- a/plugins/base/smtp.go
+++ b/plugins/base/smtp.go
@@ -3,9 +3,12 @@ package alpsbase
 import (
 	"bufio"
 	"bytes"
+	b64 "encoding/base64"
+	"encoding/binary"
 	"fmt"
 	"io"
 	"io/ioutil"
+	"math/rand"
 	"mime"
 	"mime/multipart"
 	"strings"
@@ -120,6 +123,21 @@ func writeAttachment(mw *mail.Writer, att Attachment) error {
 	return nil
 }
 
+// Message-ID format is base64 encoded epoch.rand@example.com
+func generateMessageID(domain string) string {
+	epoch := time.Now().Unix()
+	rand := rand.Int63()
+
+	messageID := base64Encode(epoch) + "." + base64Encode(rand) + domain
+	return messageID
+}
+
+func base64Encode(i int64) string {
+	buf := make([]byte, 8)
+	binary.LittleEndian.PutUint64(buf, uint64(i))
+	return b64.URLEncoding.EncodeToString(buf)
+}
+
 func (msg *OutgoingMessage) WriteTo(w io.Writer) error {
 	from := []*mail.Address{{"", msg.From}}
 
@@ -138,7 +156,8 @@ func (msg *OutgoingMessage) WriteTo(w io.Writer) error {
 	if msg.InReplyTo != "" {
 		h.Set("In-Reply-To", msg.InReplyTo)
 	}
-	// TODO: set Message-ID
+
+	h.Set("Message-ID", generateMessageID(msg.From))
 
 	mw, err := mail.CreateWriter(w, h)
 	if err != nil {
-- 
2.28.0

> Hi! I have personal interest in getting this patch upstream because it is biting a few of my users.

Hi! Thanks for your patch!

> This is a proof of concept Message-ID implementation, mostly for discussion.
>
> The format is partially gleaned from https://talk.begriffs.com/pipermail/friends/2020-August/001144.html
>
> This patch doesn't work exactly as provided, but is a rough draft of the idea - I'm sure you'd like to see
> generateMessageID moved to a different place, for example, but I wasn't sure where. So, here are my questions.
>
> todo: currently the domain isn't stripped from the from addr, but it should be trivial to do.
>
> 0. do you want have plans for this or am i stepping on toes here?

The reason I haven't done this yet is that I wanted to retain any previous
Message-Id, if the draft was composed from another client (to allow clients to
track draft changes). But I'm perfectly fine with overwriting it as a first
step.

> 1. would you like the helper functions moved to a different place? If so, where?
> 2. would you prefer to encode in base70? I chose base64 because the stdlib makes it easy.

go-message already has a helper to generate Message-Id header fields:

https://godoc.org/github.com/emersion/go-message/mail#GenerateMessageID

Can we use it instead?