Add optional inbound relay (backup-MX) behind INBOUND_RELAY_ENABLE.

Port 25 accepts only configured domains and listed recipients, then forwards to an upstream; the outbound path is unchanged when the flag is off.

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/web/handlers/handlers_inbound_test.go

@@ -0,0 +1,160 @@
+package handlers
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/mixeme/selfpost/internal/inbound"
+	"github.com/mixeme/selfpost/internal/postfix"
+	"github.com/mixeme/selfpost/internal/store"
+	"github.com/mixeme/selfpost/internal/web/auth"
+)
+
+type recordingMaps struct {
+	n int
+}
+
+func (r *recordingMaps) RebuildInboundMaps(_ []postfix.InboundRoute) error {
+	r.n++
+	return nil
+}
+
+func inboundHandlers(t *testing.T) (*Handlers, *store.Store) {
+	t.Helper()
+	st, err := store.Open(filepath.Join(t.TempDir(), "test.db"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { st.Close() })
+	v := mustView(t)
+	v.SetInboundEnabled(true)
+	h := &Handlers{
+		store:   st,
+		inbound: inbound.NewService(st, &recordingMaps{}),
+		view:    v,
+		cfg:     Config{Version: "test", InboundEnabled: true, Hostname: "mail.example.org"},
+	}
+	return h, st
+}
+
+func inboundCall(h *Handlers, method, target string, form url.Values, p auth.Principal) *httptest.ResponseRecorder {
+	rec := httptest.NewRecorder()
+	var req *http.Request
+	if form != nil {
+		req = httptest.NewRequest(method, target, strings.NewReader(form.Encode()))
+		req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	} else {
+		req = httptest.NewRequest(method, target, nil)
+	}
+	req = auth.RequestWithPrincipal(req, p)
+	if rest, ok := strings.CutPrefix(req.URL.Path, "/inbound/"); ok {
+		id, _, _ := strings.Cut(rest, "/")
+		if id != "" && id != "delete" {
+			req.SetPathValue("id", id)
+		}
+	}
+	switch {
+	case method == http.MethodGet && target == "/inbound":
+		h.HandleInboundList(rec, req)
+	case method == http.MethodPost && target == "/inbound":
+		h.HandleAddInbound(rec, req)
+	case strings.HasSuffix(target, "/delete") && method == http.MethodGet:
+		h.HandleInboundDeleteConfirm(rec, req)
+	case strings.HasSuffix(target, "/delete") && method == http.MethodPost:
+		h.HandleInboundDelete(rec, req)
+	case strings.HasSuffix(target, "/upstream"):
+		h.HandleInboundTransport(rec, req)
+	case strings.HasSuffix(target, "/recipients"):
+		h.HandleInboundRecipients(rec, req)
+	default:
+		h.HandleInboundDetail(rec, req)
+	}
+	return rec
+}
+
+func TestInboundListAndAdd(t *testing.T) {
+	h, _ := inboundHandlers(t)
+	rec := inboundCall(h, http.MethodGet, "/inbound", nil, globalPrincipal)
+	if rec.Code != http.StatusOK {
+		t.Fatalf("list = %d\n%s", rec.Code, rec.Body.String())
+	}
+	if !strings.Contains(rec.Body.String(), "Add inbound domain") {
+		t.Fatal("list missing add form")
+	}
+
+	rec = inboundCall(h, http.MethodPost, "/inbound", url.Values{"name": {"lists.example.com"}}, globalPrincipal)
+	if rec.Code != http.StatusSeeOther {
+		t.Fatalf("add = %d %s", rec.Code, rec.Body.String())
+	}
+
+	rec = inboundCall(h, http.MethodGet, "/inbound", nil, globalPrincipal)
+	if !strings.Contains(rec.Body.String(), "lists.example.com") {
+		t.Fatalf("list missing domain:\n%s", rec.Body.String())
+	}
+}
+
+func TestInboundDisabledIs404(t *testing.T) {
+	h, _ := inboundHandlers(t)
+	h.cfg.InboundEnabled = false
+	rec := inboundCall(h, http.MethodGet, "/inbound", nil, globalPrincipal)
+	if rec.Code != http.StatusNotFound {
+		t.Fatalf("disabled inbound = %d, want 404", rec.Code)
+	}
+}
+
+func TestInboundTransportAndRecipients(t *testing.T) {
+	h, st := inboundHandlers(t)
+	d, err := st.AddInboundDomain("lists.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	id := itoa(d.ID)
+
+	rec := inboundCall(h, http.MethodPost, "/inbound/"+id+"/upstream", url.Values{
+		"host": {"10.0.0.8"}, "port": {"25"}, "tls_mode": {"encrypt"},
+	}, globalPrincipal)
+	if rec.Code != http.StatusSeeOther {
+		t.Fatalf("upstream = %d %s", rec.Code, rec.Body.String())
+	}
+
+	rec = inboundCall(h, http.MethodPost, "/inbound/"+id+"/recipients", url.Values{
+		"recipient_mode": {"list"},
+		"addresses":      {"staff@lists.example.com\nabuse@other.com"},
+	}, globalPrincipal)
+	if rec.Code != http.StatusBadRequest {
+		t.Fatalf("foreign recipient = %d, want 400", rec.Code)
+	}
+
+	rec = inboundCall(h, http.MethodPost, "/inbound/"+id+"/recipients", url.Values{
+		"recipient_mode": {"list"},
+		"addresses":      {"staff@lists.example.com"},
+	}, globalPrincipal)
+	if rec.Code != http.StatusSeeOther {
+		t.Fatalf("recipients = %d %s", rec.Code, rec.Body.String())
+	}
+
+	rec = inboundCall(h, http.MethodGet, "/inbound/"+id, nil, globalPrincipal)
+	if rec.Code != http.StatusOK || !strings.Contains(rec.Body.String(), "10.0.0.8") {
+		t.Fatalf("detail =\n%s", rec.Body.String())
+	}
+}
+
+func TestInboundDelete(t *testing.T) {
+	h, st := inboundHandlers(t)
+	d, err := st.AddInboundDomain("lists.example.com")
+	if err != nil {
+		t.Fatal(err)
+	}
+	id := itoa(d.ID)
+	rec := inboundCall(h, http.MethodPost, "/inbound/"+id+"/delete", nil, globalPrincipal)
+	if rec.Code != http.StatusSeeOther {
+		t.Fatalf("delete = %d %s", rec.Code, rec.Body.String())
+	}
+	if _, err := st.GetInboundDomain(d.ID); err == nil {
+		t.Fatal("domain still present")
+	}
+}