api/v1: build responses from view accessors, not AsStruct

Serialize node, user and pre-auth-key responses through the NodeView,
UserView and PreAuthKeyView accessors instead of AsStruct(), which clones
the whole record on every read. Document the convention in AGENTS.md.

AGENTS.md

@@ -275,6 +275,11 @@ Key reminders:
   `e = e.Str("k", v)`. Forgetting to reassign silently drops the field.
 - **Tests**: prefer `hscontrol/servertest/` for server-level tests that
   don't need Docker — faster than full integration tests.
+- **View types in read paths**: response serializers must read through
+  `NodeView`/`UserView`/`PreAuthKeyView` accessors. `AsStruct()` clones the
+  whole record on every read — it is only for DB-write/merge clones and mutable
+  working copies, never to build an API response. `grep AsStruct hscontrol/api`
+  must come back empty.
 
 ## Gotchas
 

hscontrol/api/v1/nodes.go

@@ -223,7 +223,7 @@ func registerNodeReadOps(api huma.API, b Backend) {
 			// Tags-as-identity: tagged nodes are presented as the special
 			// TaggedDevices user.
 			if node.IsTagged() {
-				user := userFromState(&types.TaggedDevices)
+				user := userFromView(types.TaggedDevices.View())
 				n.User = &user
 			}
 
@@ -583,74 +583,73 @@ func registerNodeAdminOps(api huma.API, b Backend) {
 	})
 }
 
-// nodeFromView builds the Node response from a NodeView. SubnetRoutes is left
-// empty; callers that serve routes set it explicitly.
+// nodeFromView builds the Node response from a NodeView, reading through the
+// view accessors. SubnetRoutes is left empty; callers that serve routes set it
+// explicitly.
 func nodeFromView(view types.NodeView) Node {
-	node := view.AsStruct()
-
 	n := Node{
-		ID:              formatID(uint64(node.ID)),
-		MachineKey:      node.MachineKey.String(),
-		NodeKey:         node.NodeKey.String(),
-		DiscoKey:        node.DiscoKey.String(),
-		IPAddresses:     nonNilStrings(node.IPsAsString()),
-		Name:            node.Hostname,
-		CreatedAt:       node.CreatedAt,
-		RegisterMethod:  registerMethodEnum(node.RegisterMethod),
-		GivenName:       node.GivenName,
-		Online:          node.IsOnline != nil && *node.IsOnline,
-		ApprovedRoutes:  nonNilStrings(util.PrefixesToString(node.ApprovedRoutes)),
-		AvailableRoutes: nonNilStrings(util.PrefixesToString(node.AnnouncedRoutes())),
+		ID:              view.StringID(),
+		MachineKey:      view.MachineKey().String(),
+		NodeKey:         view.NodeKey().String(),
+		DiscoKey:        view.DiscoKey().String(),
+		IPAddresses:     nonNilStrings(view.IPsAsString()),
+		Name:            view.Hostname(),
+		CreatedAt:       view.CreatedAt(),
+		RegisterMethod:  registerMethodEnum(view.RegisterMethod()),
+		GivenName:       view.GivenName(),
+		Online:          view.IsOnline().Valid() && view.IsOnline().Get(),
+		ApprovedRoutes:  nonNilStrings(util.PrefixesToString(view.ApprovedRoutes().AsSlice())),
+		AvailableRoutes: nonNilStrings(util.PrefixesToString(view.AnnouncedRoutes())),
 		SubnetRoutes:    []string{},
-		Tags:            nonNilStrings(node.Tags),
+		Tags:            nonNilStrings(view.Tags().AsSlice()),
 	}
 
-	if node.User != nil {
-		user := userFromState(node.User)
+	if view.User().Valid() {
+		user := userFromView(view.User())
 		n.User = &user
 	}
 
-	if node.AuthKey != nil {
-		n.PreAuthKey = nodePreAuthKeyFromState(node.AuthKey)
+	if view.AuthKey().Valid() {
+		n.PreAuthKey = nodePreAuthKeyFromView(view.AuthKey())
 	}
 
-	if node.LastSeen != nil {
-		ls := *node.LastSeen
+	if view.LastSeen().Valid() {
+		ls := view.LastSeen().Get()
 		n.LastSeen = &ls
 	}
 
-	if node.Expiry != nil {
-		exp := *node.Expiry
+	if view.Expiry().Valid() {
+		exp := view.Expiry().Get()
 		n.Expiry = &exp
 	}
 
 	return n
 }
 
-// nodePreAuthKeyFromState builds the embedded NodePreAuthKey, masking the key to
+// nodePreAuthKeyFromView builds the embedded NodePreAuthKey, masking the key to
 // its prefix (legacy plaintext keys are shown in full).
-func nodePreAuthKeyFromState(key *types.PreAuthKey) *NodePreAuthKey {
+func nodePreAuthKeyFromView(key types.PreAuthKeyView) *NodePreAuthKey {
 	pak := &NodePreAuthKey{
-		ID:        formatID(key.ID),
+		ID:        formatID(key.ID()),
 		Key:       maskedPreAuthKey(key),
-		Reusable:  key.Reusable,
-		Ephemeral: key.Ephemeral,
-		Used:      key.Used,
-		AclTags:   nonNilStrings(key.Tags),
+		Reusable:  key.Reusable(),
+		Ephemeral: key.Ephemeral(),
+		Used:      key.Used(),
+		AclTags:   nonNilStrings(key.Tags().AsSlice()),
 	}
 
-	if key.User != nil {
-		user := userFromState(key.User)
+	if key.User().Valid() {
+		user := userFromView(key.User())
 		pak.User = &user
 	}
 
-	if key.Expiration != nil {
-		exp := *key.Expiration
+	if key.Expiration().Valid() {
+		exp := key.Expiration().Get()
 		pak.Expiration = &exp
 	}
 
-	if key.CreatedAt != nil {
-		created := *key.CreatedAt
+	if key.CreatedAt().Valid() {
+		created := key.CreatedAt().Get()
 		pak.CreatedAt = &created
 	}
 

hscontrol/api/v1/preauthkeys.go

@@ -223,7 +223,7 @@ func preAuthKeyNewToResponse(key *types.PreAuthKeyNew) PreAuthKey {
 	}
 
 	if key.User != nil {
-		u := userFromState(key.User)
+		u := userFromView(key.User.View())
 		out.User = &u
 	}
 
@@ -243,7 +243,7 @@ func preAuthKeyNewToResponse(key *types.PreAuthKeyNew) PreAuthKey {
 func preAuthKeyToResponse(key *types.PreAuthKey) PreAuthKey {
 	out := PreAuthKey{
 		ID:        formatID(key.ID),
-		Key:       maskedPreAuthKey(key),
+		Key:       maskedPreAuthKey(key.View()),
 		Reusable:  key.Reusable,
 		Ephemeral: key.Ephemeral,
 		Used:      key.Used,
@@ -251,7 +251,7 @@ func preAuthKeyToResponse(key *types.PreAuthKey) PreAuthKey {
 	}
 
 	if key.User != nil {
-		u := userFromState(key.User)
+		u := userFromView(key.User.View())
 		out.User = &u
 	}
 
@@ -269,12 +269,12 @@ func preAuthKeyToResponse(key *types.PreAuthKey) PreAuthKey {
 // maskedPreAuthKey masks new keys (those with a stored prefix) so the secret is
 // never returned; legacy plaintext keys are returned in full for backwards
 // compatibility.
-func maskedPreAuthKey(key *types.PreAuthKey) string {
-	if key.Prefix != "" {
-		return "hskey-auth-" + key.Prefix + "-***"
+func maskedPreAuthKey(key types.PreAuthKeyView) string {
+	if key.Prefix() != "" {
+		return "hskey-auth-" + key.Prefix() + "-***"
 	}
 
-	return key.Key
+	return key.Key()
 }
 
 // nonNilTags ensures aclTags serializes as [] rather than null, matching

hscontrol/api/v1/types.go

@@ -29,23 +29,24 @@ type User struct {
 	ProfilePicURL string    `json:"profilePicUrl"`
 }
 
-// userFromState converts a domain user into the v1 response shape: Name falls
-// back to Username() (email/provider/id) when the stored Name is empty, so OIDC
-// users display their email.
-func userFromState(u *types.User) User {
-	name := u.Name
+// userFromView converts a domain user into the v1 response shape, reading
+// through the [types.UserView] accessors: Name falls back to Username()
+// (email/provider/id) when the stored Name is empty, so OIDC users display
+// their email.
+func userFromView(u types.UserView) User {
+	name := u.Name()
 	if name == "" {
 		name = u.Username()
 	}
 
 	return User{
-		ID:            formatID(u.ID),
+		ID:            formatID(u.ID()),
 		Name:          name,
-		CreatedAt:     u.CreatedAt,
-		DisplayName:   u.DisplayName,
-		Email:         u.Email,
-		ProviderID:    u.ProviderIdentifier.String,
-		Provider:      u.Provider,
-		ProfilePicURL: u.ProfilePicURL,
+		CreatedAt:     u.CreatedAt(),
+		DisplayName:   u.DisplayName(),
+		Email:         u.Email(),
+		ProviderID:    u.ProviderIdentifier().String,
+		Provider:      u.Provider(),
+		ProfilePicURL: u.ProfilePicURL(),
 	}
 }

hscontrol/api/v1/users.go

@@ -93,7 +93,7 @@ func registerUsers(api huma.API, b Backend) {
 		b.Change(policyChanged)
 
 		out := &userOutput{}
-		out.Body.User = userFromState(user)
+		out.Body.User = userFromView(user.View())
 
 		return out, nil
 	})
@@ -129,7 +129,7 @@ func registerUsers(api huma.API, b Backend) {
 		}
 
 		out := &userOutput{}
-		out.Body.User = userFromState(newUser)
+		out.Body.User = userFromView(newUser.View())
 
 		return out, nil
 	})
@@ -192,7 +192,7 @@ func registerUsers(api huma.API, b Backend) {
 
 		out.Body.Users = make([]User, len(users))
 		for i := range users {
-			out.Body.Users[i] = userFromState(&users[i])
+			out.Body.Users[i] = userFromView(users[i].View())
 		}
 
 		return out, nil