release: 0.1.0: Phases 0-11: panel, Postfix/DKIM, milter, backup, Docker image

Initial feature-complete implementation of the v1.0 specification (phases 0-11 of `docs/implementation-plan.md`).
Added:
  - Panel (Go, single static binary) with SQLite persistence, one-time
  - Domain management with per-domain DKIM (RSA-2048, generated in pure Go) and
  - Application (sender identity) management: SASL credentials via `sasldb2`,
  - Full Postfix relay config generated from env at container start: SMTPS 465,
  - Journal milter (pure Go, `go-milter`) recording every send to `send_log`;
  … (6 more in CHANGELOG)

Full detail: CHANGELOG.md (0.1.0).

internal/web/middleware.go

@@ -0,0 +1,54 @@
+package web
+
+import (
+	"context"
+	"net/http"
+)
+
+type ctxKey int
+
+const usernameKey ctxKey = 0
+
+// requireAuth wraps a handler so only requests with a valid session cookie
+// reach it; everyone else is redirected to the login page. The authenticated
+// username is stashed in the request context for downstream handlers.
+//
+// It also extends the sliding session (plan B.1) on activity, defined as
+// everything except a GET request carrying HX-Request: the four monitoring
+// fragments (/status/fragment, /queue/body, /logtail/body, /sendlog/rows)
+// poll every 5s regardless of whether anyone is looking at the tab, so
+// counting those as activity would make "N days idle" mean "N days since a
+// browser tab was last open" instead.
+func (s *Server) requireAuth(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		token, ok := s.sessionToken(r)
+		if !ok {
+			http.Redirect(w, r, "/login", http.StatusSeeOther)
+			return
+		}
+		username, ok := s.sessions.Lookup(token)
+		if !ok {
+			http.Redirect(w, r, "/login", http.StatusSeeOther)
+			return
+		}
+		if isSessionActivity(r) && s.sessions.Touch(token) {
+			s.setSessionCookie(w, token)
+		}
+		ctx := context.WithValue(r.Context(), usernameKey, username)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}
+
+// isSessionActivity reports whether a request counts as administrator
+// activity for the sliding session timeout, per requireAuth's doc comment.
+func isSessionActivity(r *http.Request) bool {
+	return !(r.Method == http.MethodGet && r.Header.Get("HX-Request") != "")
+}
+
+// currentUser returns the authenticated username from the request context.
+func currentUser(r *http.Request) string {
+	if v, ok := r.Context().Value(usernameKey).(string); ok {
+		return v
+	}
+	return ""
+}