Hide candidate URLs, report unavailable notifications, clear grounded links

Release corrections from the review of promotion pull request #98:

- MQ-98-01: recipe-candidates returns an opaque candidate_id (an HMAC of
  the dinner and page under a per-process key) that the server resolves
  to the page it last offered that dinner. Candidate URLs, which may
  carry a token, no longer reach responses or the service-worker cache.
- MQ-98-02: "Turn on notifications" no longer finishes onboarding
  silently when notifications are unavailable (or denied); the step says
  plainly that nothing was turned on and offers "Finish setting up".
  The placeholder stays until Feature 19 wires Web Push.
- MQ-98-03: GroundPendingDinner clears the pasted recipe_url when
  background grounding succeeds, as manual grounding already did.

Maestro task 6819ce33-3715-4bd4-9208-a54a8b5cee02.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/dinners/dinners.go

@@ -7,6 +7,7 @@ package dinners
 
 import (
 	"context"
+	"crypto/rand"
 	"database/sql"
 	"errors"
 	"fmt"
@@ -140,6 +141,15 @@ type Service struct {
 	// by dinner id, so archiving or renaming a dinner can stop them.
 	groundingsMu sync.Mutex
 	groundings   map[string]map[*runningGrounding]struct{}
+
+	// offerKey keys the candidate ids Candidates offers, so they are
+	// opaque and stable for this process.
+	offerKey []byte
+	// offersMu guards offers: by dinner id, the page URL of each candidate
+	// id last offered by Candidates, so a candidate id is resolved here
+	// and its URL never leaves the server.
+	offersMu sync.Mutex
+	offers   map[string]map[string]string
 }
 
 // NewService returns a service over st that grounds dinners with grounder
@@ -156,7 +166,8 @@ func NewService(st *store.Store, grounder *recipes.Grounder, runner *jobs.Runner
 	case logger == nil:
 		return nil, errors.New("dinners: nil logger")
 	}
-	s := &Service{st: st, grounder: grounder, logger: logger, groundings: make(map[string]map[*runningGrounding]struct{})}
+	s := &Service{st: st, grounder: grounder, logger: logger, groundings: make(map[string]map[*runningGrounding]struct{}), offerKey: make([]byte, 32), offers: make(map[string]map[string]string)}
+	rand.Read(s.offerKey) // never fails: it crashes the program instead
 	kind, err := jobs.Register(runner, KindGroundDinner, s.runGroundJob, Reasons...)
 	if err != nil {
 		return nil, err

internal/dinners/grounding.go

@@ -2,7 +2,10 @@ package dinners
 
 import (
 	"context"
+	"crypto/hmac"
+	"crypto/sha256"
 	"database/sql"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -282,7 +285,9 @@ func reasonFor(err error, fromURL bool) string {
 
 // Candidate is a recipe page offered to ground a dinner in.
 type Candidate struct {
-	// CandidateID is the page's URL; Fix.CandidateID grounds it.
+	// CandidateID is an opaque id for the page, resolved by the server:
+	// Fix.CandidateID grounds it. The page's URL is never returned, as it
+	// may carry a token.
 	CandidateID string `json:"candidate_id"`
 	Title       string `json:"title"`
 	SiteName    string `json:"site_name"`
@@ -292,8 +297,9 @@ type Candidate struct {
 }
 
 // Candidates searches for dinner id's name and returns up to MaxCandidates
-// recipe pages to ground it in, best first; the list may be empty. A
-// search that fails wraps recipes.ErrSearchFailed.
+// recipe pages to ground it in, best first; the list may be empty. They
+// replace the dinner's earlier candidates: one not offered again no longer
+// grounds it. A search that fails wraps recipes.ErrSearchFailed.
 func (s *Service) Candidates(ctx context.Context, id string) ([]Candidate, error) {
 	row, err := s.get(ctx, id)
 	if err != nil {
@@ -304,16 +310,47 @@ func (s *Service) Candidates(ctx context.Context, id string) ([]Candidate, error
 		return nil, err
 	}
 	out := make([]Candidate, len(offers))
+	urls := make(map[string]string, len(offers))
 	for i, o := range offers {
-		out[i] = Candidate{CandidateID: o.URL, Title: o.Title, SiteName: o.SiteName, Minutes: o.Minutes}
+		cid := s.candidateID(row.ID, o.URL)
+		urls[cid] = o.URL
+		out[i] = Candidate{CandidateID: cid, Title: o.Title, SiteName: o.SiteName, Minutes: o.Minutes}
 		if o.PhotoID != "" {
 			u := PhotoURL(o.PhotoID)
 			out[i].PhotoURL = &u
 		}
 	}
+	s.offersMu.Lock()
+	s.offers[row.ID] = urls
+	s.offersMu.Unlock()
 	return out, nil
 }
 
+// candidateID is the opaque id of the page at rawURL as a candidate for
+// dinner id: the same page is offered under the same id until the service
+// restarts, and the id reveals nothing of the URL.
+func (s *Service) candidateID(id, rawURL string) string {
+	mac := hmac.New(sha256.New, s.offerKey)
+	mac.Write([]byte(id + "\x00" + rawURL))
+	return base64.RawURLEncoding.EncodeToString(mac.Sum(nil)[:16])
+}
+
+// candidateURL is the page URL of candidate cid last offered for dinner id.
+// A cid not among the dinner's candidates last offered since the service
+// started, or whose page is not a valid recipe link, is a
+// *ValidationError.
+func (s *Service) candidateURL(id, cid string) (string, error) {
+	s.offersMu.Lock()
+	raw, ok := s.offers[id][cid]
+	s.offersMu.Unlock()
+	if ok {
+		if u, err := checkRecipeURL(raw); err == nil {
+			return u.String(), nil
+		}
+	}
+	return "", invalid("candidate_id", "is not a candidate from recipe-candidates; reload the candidates")
+}
+
 // Fix grounds a dinner by hand: exactly one of a candidate from
 // Candidates, a pasted recipe link or a recipe typed in.
 type Fix struct {
@@ -367,6 +404,11 @@ func (s *Service) Ground(ctx context.Context, id string, f Fix, updatedBy string
 	if cur.Status == StatusArchived {
 		return Dinner{}, ErrArchived
 	}
+	if f.CandidateID != nil {
+		if link, err = s.candidateURL(cur.ID, *f.CandidateID); err != nil {
+			return Dinner{}, err
+		}
+	}
 	groundCtx, cancel := context.WithTimeout(ctx, groundTimeout)
 	defer cancel()
 	gr, err := s.grounder.GroundURL(groundCtx, link)
@@ -401,6 +443,9 @@ func (s *Service) Ground(ctx context.Context, id string, f Fix, updatedBy string
 	if err != nil {
 		return Dinner{}, fmt.Errorf("%w: dinner %s: record: %w", ErrGroundFailed, id, err)
 	}
+	s.offersMu.Lock()
+	delete(s.offers, cur.ID)
+	s.offersMu.Unlock()
 	return fromRow(row), nil
 }
 
@@ -550,11 +595,8 @@ func (f Fix) validate() (link string, manual *ManualRecipe, err error) {
 	}
 	switch {
 	case f.CandidateID != nil:
-		u, err := checkRecipeURL(*f.CandidateID)
-		if err != nil {
-			return "", nil, invalid("candidate_id", "is not a candidate from recipe-candidates")
-		}
-		return u.String(), nil, nil
+		// Ground resolves the candidate to its page.
+		return "", nil, nil
 	case f.RecipeURL != nil:
 		u, err := checkRecipeURL(*f.RecipeURL)
 		if err != nil {

internal/dinners/grounding_test.go

@@ -9,6 +9,7 @@ import (
 	"io/fs"
 	"log/slog"
 	"slices"
+	"strings"
 	"testing"
 	"testing/fstest"
 	"time"
@@ -214,6 +215,39 @@ func TestCreateByRecipeURLGroundsThatURL(t *testing.T) {
 	}
 }
 
+// TestCreateByRecipeURLClearsLink: once background grounding resolves a
+// pasted link, which may carry a personal token, the dinner no longer
+// stores it; the recipe it grounded in records the page.
+func TestCreateByRecipeURLClearsLink(t *testing.T) {
+	t.Parallel()
+	e := newEnv(t)
+	const link = "https://c.example/recipes/beef-stew?access_token=personal-token-abc123"
+	e.pages.Bodies[link] = recipestest.RecipePage("Beef Stew", "Stew Co", "https://c.example/stew.jpg", 150)
+	e.model.QueueGenerate(recipestest.NormalizedReply("oven", 150))
+
+	c, err := e.svc.CreateRegular(t.Context(), dinners.NewRegular{Name: ptr("Beef stew"), RecipeURL: ptr(link)}, member)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if job := e.waitJob(t, *c.GroundingJobID); job.Status != jobs.StatusSucceeded {
+		t.Fatalf("job = %+v", job)
+	}
+	row := e.dinner(t, c.ID)
+	if row.GroundingStatus != "grounded" || !row.RecipeID.Valid {
+		t.Fatalf("dinner = %+v, want grounded", row)
+	}
+	if row.RecipeUrl.Valid {
+		t.Errorf("recipe_url = %q after grounding, want cleared", row.RecipeUrl.String)
+	}
+	rec, err := db.New(e.st.Reader).GetRecipe(t.Context(), row.RecipeID.String)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if rec.SourceUrl != link {
+		t.Errorf("recipe source = %q, want %q", rec.SourceUrl, link)
+	}
+}
+
 func TestCreateGroundingFailureRecordsReason(t *testing.T) {
 	t.Parallel()
 	tests := []struct {
@@ -642,6 +676,26 @@ func failedDinner(t *testing.T, e *env, name string) string {
 	return c.ID
 }
 
+// candidateID returns the candidate_id Candidates offers dinner id for the
+// page titled title.
+func candidateID(t *testing.T, e *env, id, title string) string {
+	t.Helper()
+	got, err := e.svc.Candidates(t.Context(), id)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, c := range got {
+		if c.Title == title {
+			if strings.Contains(c.CandidateID, "://") {
+				t.Fatalf("candidate_id = %q, want an opaque id, not the page URL", c.CandidateID)
+			}
+			return c.CandidateID
+		}
+	}
+	t.Fatalf("candidates = %+v, want one titled %q", got, title)
+	return ""
+}
+
 func TestCandidates(t *testing.T) {
 	t.Parallel()
 	e := newEnv(t)
@@ -664,14 +718,25 @@ func TestCandidates(t *testing.T) {
 	}
 	first, second := got[0], got[1]
 	wantPhoto := dinners.PhotoURL(e.dinner(t, c.ID).PhotoID.String)
-	if first.CandidateID != curryA || first.Title != "Chicken Curry" || first.SiteName != "Curry House" ||
+	if first.Title != "Chicken Curry" || first.SiteName != "Curry House" ||
 		first.PhotoURL == nil || *first.PhotoURL != wantPhoto || first.Minutes == nil || *first.Minutes != 40 {
 		t.Errorf("first = %+v, want the stored curryA with photo %s", first, wantPhoto)
 	}
-	if second.CandidateID != curryB || second.Title != "Easy Weeknight Curry" || second.SiteName != "B Kitchen" ||
+	if second.Title != "Easy Weeknight Curry" || second.SiteName != "B Kitchen" ||
 		second.PhotoURL != nil || second.Minutes == nil || *second.Minutes != 25 {
 		t.Errorf("second = %+v, want curryB without a photo", second)
 	}
+	if first.CandidateID == "" || first.CandidateID == second.CandidateID ||
+		first.CandidateID == curryA || second.CandidateID == curryB {
+		t.Errorf("candidate ids = %q, %q, want distinct opaque ids", first.CandidateID, second.CandidateID)
+	}
+	again, err := e.svc.Candidates(t.Context(), c.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(again) != 2 || again[0].CandidateID != first.CandidateID || again[1].CandidateID != second.CandidateID {
+		t.Errorf("candidates again = %+v, want the same ids", again)
+	}
 
 	if _, err := e.svc.Candidates(t.Context(), "nope"); !errors.Is(err, dinners.ErrNotFound) {
 		t.Errorf("unknown dinner: err = %v, want ErrNotFound", err)
@@ -702,9 +767,11 @@ func TestFixViaCandidate(t *testing.T) {
 	t.Parallel()
 	e := newEnv(t)
 	id := failedDinner(t, e, "Mystery curry")
+	e.search.Results["Mystery curry"] = []recipes.Candidate{{URL: curryA}, {URL: curryB}}
+	cid := candidateID(t, e, id, "Easy Weeknight Curry")
 	e.model.QueueGenerate(recipestest.NormalizedReply("stovetop", 25))
 
-	d, err := e.svc.Ground(t.Context(), id, dinners.Fix{CandidateID: ptr(curryB)}, "member-2")
+	d, err := e.svc.Ground(t.Context(), id, dinners.Fix{CandidateID: ptr(cid)}, "member-2")
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -729,12 +796,18 @@ func TestFixReplacesPendingLink(t *testing.T) {
 	const lost = "https://gone.example/recipes/lamb-tagine"
 	tests := []struct {
 		name string
-		fix  dinners.Fix
+		// fix is the fix for dinner id.
+		fix func(t *testing.T, e *env, id string) dinners.Fix
 		// linkTaken is the recipe link the fixed dinner now has, if any.
 		linkTaken string
 	}{
-		{"candidate", dinners.Fix{CandidateID: ptr(curryB)}, curryB},
-		{"manual", dinners.Fix{Manual: &dinners.ManualRecipe{Ingredients: []string{"1 lamb"}, Minutes: ptr(90), Method: ptr("oven")}}, ""},
+		{"candidate", func(t *testing.T, e *env, id string) dinners.Fix {
+			e.search.Results["Weeknight dinner"] = []recipes.Candidate{{URL: curryB}}
+			return dinners.Fix{CandidateID: ptr(candidateID(t, e, id, "Easy Weeknight Curry"))}
+		}, curryB},
+		{"manual", func(*testing.T, *env, string) dinners.Fix {
+			return dinners.Fix{Manual: &dinners.ManualRecipe{Ingredients: []string{"1 lamb"}, Minutes: ptr(90), Method: ptr("oven")}}
+		}, ""},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -752,7 +825,7 @@ func TestFixReplacesPendingLink(t *testing.T) {
 				t.Fatal(err)
 			}
 			e.model.QueueGenerate(recipestest.NormalizedReply("stovetop", 25))
-			if _, err := e.svc.Ground(t.Context(), c.ID, tt.fix, member); err != nil {
+			if _, err := e.svc.Ground(t.Context(), c.ID, tt.fix(t, e, c.ID), member); err != nil {
 				t.Fatal(err)
 			}
 			row, err := db.New(e.st.Reader).GetDinner(t.Context(), c.ID)
@@ -855,7 +928,8 @@ func TestFixValidation(t *testing.T) {
 	tests := map[string]dinners.Fix{
 		"nothing":           {},
 		"two":               {CandidateID: ptr(curryA), RecipeURL: ptr(stew)},
-		"candidate not URL": {CandidateID: ptr("cand-1")},
+		"unknown candidate": {CandidateID: ptr("cand-1")},
+		"candidate a URL":   {CandidateID: ptr(curryA)},
 		"http link":         {RecipeURL: ptr("http://a.example/x")},
 		"no ingredients":    {Manual: &dinners.ManualRecipe{Minutes: ptr(20), Method: ptr("oven")}},
 		"blank ingredient":  {Manual: &dinners.ManualRecipe{Ingredients: []string{" "}, Minutes: ptr(20), Method: ptr("oven")}},