1 files changed, 34 insertions, 0 deletions
diff --git a/lib/msgid.go b/lib/msgid.go
new file mode 100644
index 00000000..8282d1d6
--- /dev/null
+++ b/lib/msgid.go
@@ -0,0 +1,34 @@
+package lib
+
+// TODO: Remove this pending merge into github.com/emersion/go-message
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"math/rand"
+	"os"
+	"time"
+
+	"github.com/martinlindhe/base36"
+)
+
+// Generates an RFC 2822-complaint Message-Id based on the informational draft
+// "Recommendations for generating Message IDs", for lack of a better
+// authoritative source.
+func GenerateMessageId() string {
+	var (
+		now   bytes.Buffer
+		nonce bytes.Buffer
+	)
+	binary.Write(&now, binary.BigEndian, time.Now().UnixNano())
+	binary.Write(&nonce, binary.BigEndian, rand.Uint64())
+	hostname, err := os.Hostname()
+	if err != nil {
+		hostname = "localhost"
+	}
+	return fmt.Sprintf("<%s.%s@%s>",
+		base36.EncodeBytes(now.Bytes()),
+		base36.EncodeBytes(nonce.Bytes()),
+		hostname)
+}