release: 0.6.0: Delivery detail page, DNS badge, machine metrics, wide layout

A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
Added:
  - A page per delivery (`/deliveries/{id}`), reached from the *Details* link on
  - A **DNS** badge in the domain list, one per row, carrying the same
  - Machine metrics on the status page: a **Machine** card reporting the
  - An index of the current page's own sections in the navigation column, for the
Changed:
  - Every panel page is laid out in one column of the same width, so moving
  - The mark's small-size variant — the tab icon and the `SP` initials it
  - The stamp's `SELF-HOSTED SMTP RELAY` line is set at 11.5/0.15 instead of
  - The delivery log lists what identifies a message and nothing else: time,
  - Subjects are decoded for display as well as on the way in, so the rows the
  … (4 more in CHANGELOG)

Full detail: CHANGELOG.md (0.6.0).

internal/mailhdr/subject.go

@@ -0,0 +1,38 @@
+// Package mailhdr turns raw mail header values into display text. It sits
+// between the journal-milter, which reads headers off the wire, and the panel,
+// which shows them: both need the same answer for the same header, and the
+// panel needs it for rows the milter wrote before this decoding existed.
+package mailhdr
+
+import (
+	"mime"
+	"strings"
+)
+
+// SubjectMaxRunes caps what the journal keeps of a subject. A Subject header
+// may legally run to hundreds of characters; the log only needs enough to
+// recognise the message, and the panel shows one row per recipient.
+const SubjectMaxRunes = 200
+
+// DecodeSubject turns a raw Subject header into display text. Anything
+// non-ASCII arrives as RFC 2047 encoded-words (=?utf-8?Q?=D0=9F…?=), which the
+// panel would otherwise show verbatim: unreadable, and — being one unbreakable
+// run — wide enough to push the send-log table out of its card. Go's decoder
+// covers the UTF-8 and ASCII charsets senders use in practice; for anything
+// else (windows-1251, koi8-r) it fails and the raw header is kept, which is no
+// worse than not decoding at all. Truncation is applied after decoding so the
+// cap counts characters of the subject, not bytes of its encoding.
+//
+// It is idempotent: already-decoded text contains no encoded-words, so a second
+// pass returns it unchanged. That is what lets the panel decode on the way out
+// as well as the milter on the way in.
+func DecodeSubject(v string) string {
+	if dec, err := (&mime.WordDecoder{}).DecodeHeader(v); err == nil {
+		v = dec
+	}
+	v = strings.TrimSpace(v)
+	if r := []rune(v); len(r) > SubjectMaxRunes {
+		v = string(r[:SubjectMaxRunes]) + "…"
+	}
+	return v
+}

internal/mailhdr/subject_test.go

@@ -0,0 +1,38 @@
+package mailhdr
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestDecodeSubject(t *testing.T) {
+	long := strings.Repeat("я", SubjectMaxRunes+10)
+
+	for _, tc := range []struct {
+		name, raw, want string
+	}{
+		{"plain", "Hello there", "Hello there"},
+		{"utf8 q", "=?utf-8?Q?=D0=9F=D1=80=D0=BE=D0=B2=D0=B5=D1=80=D0=BA=D0=B0?=", "Проверка"},
+		{"utf8 b, folded across two words", "=?utf-8?B?0J/RgNC40LLQtdGC?=\r\n =?utf-8?B?INC80LjRgA==?=", "Привет мир"},
+		// No decoder for the legacy single-byte charsets: keep the header as
+		// sent rather than losing the subject entirely.
+		{"unknown charset", "=?windows-1251?B?z/Do4uXy?=", "=?windows-1251?B?z/Do4uXy?="},
+		{"too long", long, strings.Repeat("я", SubjectMaxRunes) + "…"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			if got := DecodeSubject(tc.raw); got != tc.want {
+				t.Fatalf("DecodeSubject(%q) = %q, want %q", tc.raw, got, tc.want)
+			}
+		})
+	}
+}
+
+// The panel decodes on the way out as well as the milter on the way in, so
+// every already-decoded row in the send log passes through a second time.
+func TestDecodeSubjectIsIdempotent(t *testing.T) {
+	for _, s := range []string{"Проверка", "Hello there", "", "=?windows-1251?B?z/Do4uXy?="} {
+		if got := DecodeSubject(DecodeSubject(s)); got != DecodeSubject(s) {
+			t.Fatalf("second pass over %q changed it to %q", s, got)
+		}
+	}
+}