Add VAPID config and the push subscription API

Require MEALQUEST_VAPID_PUBLIC_KEY, MEALQUEST_VAPID_PRIVATE_KEY_FILE and MEALQUEST_VAPID_SUBJECT at boot. Both keys are unpadded base64url P-256 keys, the encoding webpush-go reads; boot derives the public point from the private key and refuses a pair that does not match. The subject must be mailto:<address> or an https:// URL. internal/push stores subscriptions by endpoint: GET /api/v1/push/vapid-public-key serves only the public key, POST /api/v1/push/subscriptions upserts {endpoint, keys.p256dh, keys.auth, user_agent}, and DELETE removes by endpoint, answering 204 whether or not it was stored. cmd/vapidgen prints a new key pair. deploy/compose.yaml mounts the vapid_private_key secret. Maestro task e8a7b1f4-327a-478b-88c7-5d265afda153. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
2026-10-09 08:03:59 -04:00
parent cb451baed4
commit f1e7503f94
30 changed files with 1526 additions and 36 deletions
@@ -0,0 +1,203 @@
+// Package push keeps the household's Web Push subscriptions, one per
+// browser, keyed by the push service endpoint the browser was given, and
+// the VAPID public key browsers subscribe with.
+package push
+
+import (
+	"context"
+	"crypto/ecdh"
+	"database/sql"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"net/url"
+	"strings"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/vapid"
+)
+
+// Limits on a subscription's fields.
+const (
+	MaxEndpointBytes  = 2048
+	MaxUserAgentBytes = 512
+	p256dhSize        = 65 // uncompressed P-256 point
+	authSize          = 16
+)
+
+// keyEncoding is the unpadded base64url PushSubscription.toJSON() gives
+// the keys in.
+var keyEncoding = base64.RawURLEncoding
+
+// Subscription is a stored push subscription. Its keys are never returned:
+// only the sender needs them.
+type Subscription struct {
+	ID        string  `json:"id"`
+	Endpoint  string  `json:"endpoint"`
+	UserAgent *string `json:"user_agent"`
+	CreatedAt string  `json:"created_at"`
+	UpdatedAt string  `json:"updated_at"`
+}
+
+// SubscribeRequest is a browser's push subscription: the endpoint and keys
+// of its PushSubscription, and optionally a user agent to tell the
+// household's devices apart.
+type SubscribeRequest struct {
+	Endpoint  string
+	P256dh    string
+	Auth      string
+	UserAgent *string
+}
+
+// Problem is one invalid field of a request, named by its JSON key.
+type Problem struct {
+	Field  string
+	Reason string
+}
+
+// ValidationError lists every invalid field of a request.
+type ValidationError struct {
+	Problems []Problem
+}
+
+func (e *ValidationError) Error() string {
+	parts := make([]string, len(e.Problems))
+	for i, p := range e.Problems {
+		parts[i] = p.Field + ": " + p.Reason
+	}
+	return "invalid push subscription: " + strings.Join(parts, "; ")
+}
+
+// Service stores push subscriptions.
+type Service struct {
+	st        *store.Store
+	publicKey string
+}
+
+// NewService returns a Service over st handing out publicKey, the VAPID
+// public key in vapid's encoding.
+func NewService(st *store.Store, publicKey string) (*Service, error) {
+	if st == nil {
+		return nil, errors.New("push: nil store")
+	}
+	if _, err := vapid.ParsePublicKey(publicKey); err != nil {
+		return nil, fmt.Errorf("push: VAPID public key: %w", err)
+	}
+	return &Service{st: st, publicKey: publicKey}, nil
+}
+
+// PublicKey returns the VAPID public key, for applicationServerKey.
+func (s *Service) PublicKey() string { return s.publicKey }
+
+// Subscribe stores req by its endpoint. An endpoint already stored keeps
+// its id and created_at and has its keys and user agent replaced, so
+// subscribing twice leaves one subscription. An invalid request is a
+// *ValidationError.
+func (s *Service) Subscribe(ctx context.Context, req SubscribeRequest) (Subscription, error) {
+	var problems []Problem
+	if reason := checkEndpoint(req.Endpoint); reason != "" {
+		problems = append(problems, Problem{"endpoint", reason})
+	}
+	if reason := checkP256dh(req.P256dh); reason != "" {
+		problems = append(problems, Problem{"keys.p256dh", reason})
+	}
+	if reason := checkAuth(req.Auth); reason != "" {
+		problems = append(problems, Problem{"keys.auth", reason})
+	}
+	var ua sql.NullString
+	if req.UserAgent != nil {
+		if reason := checkUserAgent(*req.UserAgent); reason != "" {
+			problems = append(problems, Problem{"user_agent", reason})
+		}
+		ua = sql.NullString{String: *req.UserAgent, Valid: true}
+	}
+	if len(problems) > 0 {
+		return Subscription{}, &ValidationError{Problems: problems}
+	}
+
+	now := store.Now().String()
+	row, err := db.New(s.st.Writer).UpsertPushSubscription(ctx, db.UpsertPushSubscriptionParams{
+		ID:        store.NewID(),
+		Endpoint:  req.Endpoint,
+		P256dh:    req.P256dh,
+		Auth:      req.Auth,
+		UserAgent: ua,
+		CreatedAt: now,
+		UpdatedAt: now,
+	})
+	if err != nil {
+		return Subscription{}, fmt.Errorf("push: store subscription: %w", err)
+	}
+	sub := Subscription{ID: row.ID, Endpoint: row.Endpoint, CreatedAt: row.CreatedAt, UpdatedAt: row.UpdatedAt}
+	if row.UserAgent.Valid {
+		sub.UserAgent = &row.UserAgent.String
+	}
+	return sub, nil
+}
+
+// Unsubscribe removes the subscription for endpoint and reports whether
+// one was stored. An endpoint that is not stored is not an error: the
+// browser may unsubscribe after a failed delivery already removed it. An
+// invalid endpoint is a *ValidationError.
+func (s *Service) Unsubscribe(ctx context.Context, endpoint string) (bool, error) {
+	if reason := checkEndpoint(endpoint); reason != "" {
+		return false, &ValidationError{Problems: []Problem{{"endpoint", reason}}}
+	}
+	n, err := db.New(s.st.Writer).DeletePushSubscription(ctx, endpoint)
+	if err != nil {
+		return false, fmt.Errorf("push: delete subscription: %w", err)
+	}
+	return n > 0, nil
+}
+
+// checkEndpoint returns why endpoint is not a push service URL, or "".
+// Push services are always reached over https.
+func checkEndpoint(endpoint string) string {
+	if endpoint == "" {
+		return "required"
+	}
+	if len(endpoint) > MaxEndpointBytes {
+		return fmt.Sprintf("longer than %d bytes", MaxEndpointBytes)
+	}
+	u, err := url.Parse(endpoint)
+	if err != nil || u.Scheme != "https" || u.Host == "" || u.User != nil || u.Fragment != "" {
+		return "want an absolute https:// URL without credentials or fragment"
+	}
+	return ""
+}
+
+func checkP256dh(s string) string {
+	if s == "" {
+		return "required"
+	}
+	b, err := keyEncoding.DecodeString(s)
+	if err != nil || len(b) != p256dhSize {
+		return fmt.Sprintf("want the %d-byte uncompressed P-256 point in unpadded base64url", p256dhSize)
+	}
+	if _, err := ecdh.P256().NewPublicKey(b); err != nil {
+		return "not a point on P-256"
+	}
+	return ""
+}
+
+func checkAuth(s string) string {
+	if s == "" {
+		return "required"
+	}
+	b, err := keyEncoding.DecodeString(s)
+	if err != nil || len(b) != authSize {
+		return fmt.Sprintf("want %d bytes in unpadded base64url", authSize)
+	}
+	return ""
+}
+
+func checkUserAgent(s string) string {
+	switch {
+	case strings.TrimSpace(s) == "":
+		return "must not be blank; omit it instead"
+	case len(s) > MaxUserAgentBytes:
+		return fmt.Sprintf("longer than %d bytes", MaxUserAgentBytes)
+	}
+	return ""
+}
@@ -0,0 +1,224 @@
+package push
+
+import (
+	"context"
+	"crypto/ecdh"
+	"crypto/rand"
+	"encoding/base64"
+	"errors"
+	"strings"
+	"testing"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/vapid"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/migrations"
+)
+
+const endpoint = "https://fcm.googleapis.com/fcm/send/abc123"
+
+func newTestService(t *testing.T) (*Service, *store.Store) {
+	t.Helper()
+	ctx := context.Background()
+	st, err := store.Open(ctx, t.TempDir())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		if err := st.Close(); err != nil {
+			t.Error(err)
+		}
+	})
+	if err := store.Migrate(ctx, st.Writer, migrations.FS); err != nil {
+		t.Fatal(err)
+	}
+	pair, err := vapid.Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	svc, err := NewService(st, pair.PublicKey)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return svc, st
+}
+
+// browserKeys returns a p256dh and auth as a browser's
+// PushSubscription.toJSON() gives them.
+func browserKeys(t *testing.T) (string, string) {
+	t.Helper()
+	k, err := ecdh.P256().GenerateKey(rand.Reader)
+	if err != nil {
+		t.Fatal(err)
+	}
+	auth := make([]byte, 16)
+	rand.Read(auth)
+	return base64.RawURLEncoding.EncodeToString(k.PublicKey().Bytes()), base64.RawURLEncoding.EncodeToString(auth)
+}
+
+type storedRow struct {
+	id, p256dh, auth, createdAt, updatedAt string
+	ua                                     *string
+	failures                               int
+}
+
+func rows(t *testing.T, st *store.Store) map[string]storedRow {
+	t.Helper()
+	rs, err := st.Reader.Query(`SELECT endpoint, id, p256dh, auth, user_agent, failure_count, created_at, updated_at FROM push_subscriptions`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rs.Close()
+	got := map[string]storedRow{}
+	for rs.Next() {
+		var ep string
+		var r storedRow
+		if err := rs.Scan(&ep, &r.id, &r.p256dh, &r.auth, &r.ua, &r.failures, &r.createdAt, &r.updatedAt); err != nil {
+			t.Fatal(err)
+		}
+		got[ep] = r
+	}
+	if err := rs.Err(); err != nil {
+		t.Fatal(err)
+	}
+	return got
+}
+
+func TestNewServiceRefusesBadPublicKey(t *testing.T) {
+	t.Parallel()
+	_, st := newTestService(t)
+	if _, err := NewService(st, "not-a-key"); err == nil {
+		t.Error("NewService accepted a malformed public key")
+	}
+	if _, err := NewService(nil, ""); err == nil {
+		t.Error("NewService accepted a nil store")
+	}
+}
+
+func TestSubscribeUpsertsByEndpoint(t *testing.T) {
+	t.Parallel()
+	svc, st := newTestService(t)
+	ctx := context.Background()
+	p1, a1 := browserKeys(t)
+	ua := "Mozilla/5.0 (iPad)"
+
+	first, err := svc.Subscribe(ctx, SubscribeRequest{Endpoint: endpoint, P256dh: p1, Auth: a1, UserAgent: &ua})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if first.ID == "" || first.Endpoint != endpoint || first.UserAgent == nil || *first.UserAgent != ua || first.CreatedAt != first.UpdatedAt {
+		t.Errorf("first Subscribe = %+v", first)
+	}
+	if _, err := st.Writer.Exec(`UPDATE push_subscriptions SET failure_count = 3`); err != nil {
+		t.Fatal(err)
+	}
+
+	// The same endpoint again, with the same keys and then rotated ones,
+	// updates the one row.
+	again, err := svc.Subscribe(ctx, SubscribeRequest{Endpoint: endpoint, P256dh: p1, Auth: a1, UserAgent: &ua})
+	if err != nil {
+		t.Fatal(err)
+	}
+	p2, a2 := browserKeys(t)
+	rotated, err := svc.Subscribe(ctx, SubscribeRequest{Endpoint: endpoint, P256dh: p2, Auth: a2})
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, s := range []Subscription{again, rotated} {
+		if s.ID != first.ID || s.CreatedAt != first.CreatedAt {
+			t.Errorf("resubscribe = %+v, want id %s and created_at %s kept", s, first.ID, first.CreatedAt)
+		}
+	}
+	if rotated.UserAgent != nil {
+		t.Errorf("resubscribe without user_agent kept %q", *rotated.UserAgent)
+	}
+	got := rows(t, st)
+	if len(got) != 1 {
+		t.Fatalf("rows = %d, want 1: %+v", len(got), got)
+	}
+	r := got[endpoint]
+	if r.p256dh != p2 || r.auth != a2 || r.ua != nil || r.failures != 0 || r.updatedAt < r.createdAt {
+		t.Errorf("stored row = %+v, want rotated keys, no user agent, failures cleared", r)
+	}
+
+	// A second browser is a second row.
+	other := endpoint + "-other"
+	if _, err := svc.Subscribe(ctx, SubscribeRequest{Endpoint: other, P256dh: p1, Auth: a1}); err != nil {
+		t.Fatal(err)
+	}
+	if got := rows(t, st); len(got) != 2 {
+		t.Errorf("rows after a second endpoint = %d, want 2", len(got))
+	}
+}
+
+func TestUnsubscribe(t *testing.T) {
+	t.Parallel()
+	svc, st := newTestService(t)
+	ctx := context.Background()
+	p, a := browserKeys(t)
+	for _, ep := range []string{endpoint, endpoint + "-keep"} {
+		if _, err := svc.Subscribe(ctx, SubscribeRequest{Endpoint: ep, P256dh: p, Auth: a}); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	removed, err := svc.Unsubscribe(ctx, endpoint)
+	if err != nil || !removed {
+		t.Errorf("Unsubscribe = %v, %v; want true, nil", removed, err)
+	}
+	got := rows(t, st)
+	if _, ok := got[endpoint]; ok || len(got) != 1 {
+		t.Errorf("rows after Unsubscribe = %+v, want only the other endpoint", got)
+	}
+	removed, err = svc.Unsubscribe(ctx, endpoint)
+	if err != nil || removed {
+		t.Errorf("Unsubscribe of an endpoint not stored = %v, %v; want false, nil", removed, err)
+	}
+	var invalid *ValidationError
+	if _, err := svc.Unsubscribe(ctx, "http://push.example.com/x"); !errors.As(err, &invalid) {
+		t.Errorf("Unsubscribe of an http endpoint = %v, want *ValidationError", err)
+	}
+}
+
+func TestSubscribeValidates(t *testing.T) {
+	t.Parallel()
+	svc, st := newTestService(t)
+	p, a := browserKeys(t)
+	pair, err := vapid.Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+	blank, long := "  ", strings.Repeat("x", MaxUserAgentBytes+1)
+	offCurve := make([]byte, 65)
+	offCurve[0] = 0x04
+	raw := base64.RawURLEncoding.EncodeToString
+
+	for _, tc := range []struct {
+		name  string
+		req   SubscribeRequest
+		field string
+	}{
+		{"missing endpoint", SubscribeRequest{P256dh: p, Auth: a}, "endpoint"},
+		{"http endpoint", SubscribeRequest{Endpoint: "http://push.example.com/x", P256dh: p, Auth: a}, "endpoint"},
+		{"relative endpoint", SubscribeRequest{Endpoint: "/fcm/send/x", P256dh: p, Auth: a}, "endpoint"},
+		{"endpoint with credentials", SubscribeRequest{Endpoint: "https://u:p@push.example.com/x", P256dh: p, Auth: a}, "endpoint"},
+		{"endpoint too long", SubscribeRequest{Endpoint: "https://push.example.com/" + strings.Repeat("x", MaxEndpointBytes), P256dh: p, Auth: a}, "endpoint"},
+		{"missing p256dh", SubscribeRequest{Endpoint: endpoint, Auth: a}, "keys.p256dh"},
+		{"padded p256dh", SubscribeRequest{Endpoint: endpoint, P256dh: p + "=", Auth: a}, "keys.p256dh"},
+		{"short p256dh", SubscribeRequest{Endpoint: endpoint, P256dh: a, Auth: a}, "keys.p256dh"},
+		{"p256dh off the curve", SubscribeRequest{Endpoint: endpoint, P256dh: raw(offCurve), Auth: a}, "keys.p256dh"},
+		{"private key as p256dh", SubscribeRequest{Endpoint: endpoint, P256dh: pair.PrivateKey, Auth: a}, "keys.p256dh"},
+		{"missing auth", SubscribeRequest{Endpoint: endpoint, P256dh: p}, "keys.auth"},
+		{"long auth", SubscribeRequest{Endpoint: endpoint, P256dh: p, Auth: raw(make([]byte, 32))}, "keys.auth"},
+		{"blank user agent", SubscribeRequest{Endpoint: endpoint, P256dh: p, Auth: a, UserAgent: &blank}, "user_agent"},
+		{"long user agent", SubscribeRequest{Endpoint: endpoint, P256dh: p, Auth: a, UserAgent: &long}, "user_agent"},
+	} {
+		_, err := svc.Subscribe(context.Background(), tc.req)
+		var invalid *ValidationError
+		if !errors.As(err, &invalid) || len(invalid.Problems) != 1 || invalid.Problems[0].Field != tc.field {
+			t.Errorf("%s: Subscribe error = %v, want one problem for %s", tc.name, err, tc.field)
+		}
+	}
+	if got := rows(t, st); len(got) != 0 {
+		t.Errorf("invalid requests stored %d rows", len(got))
+	}
+}