commit 184e4de6a4897b14d1f75b9a95ff5b7eb957f543
from: Oliver Lowe <o@olowe.co>
date: Wed Mar 13 04:09:32 2024 UTC

apub: tighten up content-type on marshalling into mail

Clearer: set a body to read from, then change it when necessary. Fewer
instructions! Also, mail clients don't really know what to do with
text/markdown, so just use text/plain; that's what Gruber would want.

Adds basic test case too

commit - 519acee1bbf60fee276fd734f7a8254edd803d06
commit + 184e4de6a4897b14d1f75b9a95ff5b7eb957f543
blob - c6912852868287f8120ed9ccadf48ce62e7f59d2
blob + 987fe41861005415060cbedec17837b1a16591b5
--- mail.go
+++ mail.go
@@ -59,20 +59,18 @@ func MarshalMail(activity *Activity) ([]byte, error) {
 		fmt.Fprintf(buf, "References: <%s>\n", activity.InReplyTo)
 	}
 
+	body := &activity.Content
 	if activity.Source.Content != "" && activity.Source.MediaType == "text/markdown" {
+		body = &activity.Source.Content
 		fmt.Fprintln(buf, "Content-Type: text/plain; charset=utf-8")
-	} else if activity.MediaType != "" {
-		fmt.Fprintln(buf, "Content-Type:", activity.MediaType)
+	} else if activity.MediaType == "text/markdown" {
+		fmt.Fprintln(buf, "Content-Type: text/plain; charset=utf-8")
 	} else {
 		fmt.Fprintln(buf, "Content-Type:", "text/html; charset=utf-8")
 	}
 	fmt.Fprintln(buf, "Subject:", activity.Name)
 	fmt.Fprintln(buf)
-	if activity.Source.Content != "" && activity.Source.MediaType == "text/markdown" {
-		fmt.Fprintln(buf, activity.Source.Content)
-	} else {
-		fmt.Fprintln(buf, activity.Content)
-	}
+	fmt.Fprintln(buf, *body)
 	_, err = mail.ReadMessage(bytes.NewReader(buf.Bytes()))
 	return buf.Bytes(), err
 }
blob - 61bf051284c44bab0c9c0ee8b84609ae5bcdff77
blob + fe6864206e60fa17becbdec36ffe8bd64e15b13f
--- mail_test.go
+++ mail_test.go
@@ -75,9 +75,24 @@ func TestMarshalMail(t *testing.T) {
 			t.Errorf("%s: marshal to mail message: %v", name, err)
 			continue
 		}
-		if _, err := mail.ReadMessage(bytes.NewReader(b)); err != nil {
+		msg, err := mail.ReadMessage(bytes.NewReader(b))
+		if err != nil {
 			t.Errorf("%s: read back message from marshalled activity: %v", name, err)
+			continue
 		}
+		p := make([]byte, 8)
+		n, err := msg.Body.Read(p)
+		if err != nil {
+			t.Errorf("%s: read message body: %v", name, err)
+		}
+		if n != len(p) {
+			if a.Type == "Page" {
+				// Pages have no content, so skip this case
+				continue
+			}
+			t.Errorf("%s: short read from body", name)
+			t.Log(string(p))
+		}
 	}
 }