Add user-message client subsystem

backend/radiance.go

@@ -21,6 +21,7 @@ import (
 	"go.opentelemetry.io/otel/trace"
 
 	C "github.com/getlantern/common"
+	wire "github.com/getlantern/common/usermessage"
 	"github.com/getlantern/publicip"
 
 	"github.com/getlantern/radiance/account"
@@ -38,6 +39,7 @@ import (
 	"github.com/getlantern/radiance/telemetry"
 	"github.com/getlantern/radiance/traces"
 	"github.com/getlantern/radiance/unbounded"
+	clientmessage "github.com/getlantern/radiance/usermessage"
 	"github.com/getlantern/radiance/vpn"
 
 	lbA "github.com/getlantern/lantern-box/adapter"
@@ -57,6 +59,7 @@ type LocalBackend struct {
 	confHandler   *config.ConfigHandler
 	issueReporter *issue.IssueReporter
 	accountClient *account.Client
+	userMessages  *clientmessage.Service
 
 	srvManager     *servers.Manager
 	vpnClient      *vpn.VPNClient
@@ -227,13 +230,40 @@ func NewLocalBackend(ctx context.Context, opts Options) (*LocalBackend, error) {
 	}
 	r.sessionHistory = vpn.NewSessionHistory(slog.Default().With("service", "session_history"), r.sessionInfo())
 	r.shutdownFuncs = append(r.shutdownFuncs, func() error { r.sessionHistory.Close(); return nil })
+	userMessages, err := clientmessage.New(clientmessage.Options{
+		DataDir: dataDir,
+		Fetcher: clientmessage.NewHTTPFetcher(
+			kindling.HTTPClient(),
+			clientmessage.Endpoint(common.GetBaseURL()),
+		),
+		ContextProvider: func() clientmessage.ClientContext {
+			return clientmessage.ClientContext{
+				UserID:     settings.GetString(settings.UserIDKey),
+				ProToken:   settings.GetString(settings.TokenKey),
+				Locale:     clientmessage.NormalizeLocale(settings.GetString(settings.LocaleKey)),
+				Platform:   clientmessage.NormalizePlatform(common.Platform),
+				AppVersion: common.GetVersion(),
+			}
+		},
+	})
+	if err != nil {
+		slog.Error("Loading user-message state", "error", err)
+	} else {
+		r.userMessages = userMessages
+	}
 	r.clearSelectedIfMissing()
 	return r, nil
 }
 
 func (r *LocalBackend) Start() {
 	// eagerly start kindling so it's ready by the time we need to make network requests
 	kindling.Init()
+	if r.userMessages != nil {
+		events.SubscribeContext(r.ctx, func(account.UserChangeEvent) {
+			r.userMessages.Refresh()
+		})
+		r.userMessages.Start(r.ctx)
+	}
 	go func() {
 		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
 		result, err := publicip.Detect(ctx, &publicip.Config{
@@ -601,6 +631,9 @@ func (r *LocalBackend) PatchSettings(updates settings.Settings) error {
 	if err := settings.Patch(diff); err != nil {
 		return fmt.Errorf("failed to update settings: %w", err)
 	}
+	if _, ok := diff[settings.LocaleKey]; ok {
+		r.refreshUserMessages()
+	}
 	// telemetry settings
 	if _, ok := diff[settings.TelemetryKey]; ok {
 		if settings.GetBool(settings.TelemetryKey) {
@@ -1548,19 +1581,35 @@ func (r *LocalBackend) RemoveSplitTunnelItems(items vpn.SplitTunnelFilter) error
 /////////////
 
 func (r *LocalBackend) NewUser(ctx context.Context) (*account.UserData, error) {
-	return r.accountClient.NewUser(ctx)
+	userData, err := r.accountClient.NewUser(ctx)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) Login(ctx context.Context, email, password string) (*account.UserData, error) {
-	return r.accountClient.Login(ctx, email, password)
+	userData, err := r.accountClient.Login(ctx, email, password)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) Logout(ctx context.Context, email string) (*account.UserData, error) {
-	return r.accountClient.Logout(ctx, email)
+	userData, err := r.accountClient.Logout(ctx, email)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) FetchUserData(ctx context.Context) (*account.UserData, error) {
-	return r.accountClient.FetchUserData(ctx)
+	userData, err := r.accountClient.FetchUserData(ctx)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) VerifyPassword(ctx context.Context, email, password string) error {
@@ -1585,7 +1634,11 @@ func (r *LocalBackend) CompleteRecoveryByEmail(ctx context.Context, email, newPa
 }
 
 func (r *LocalBackend) DeleteAccount(ctx context.Context, email, password string) (*account.UserData, error) {
-	return r.accountClient.DeleteAccount(ctx, email, password)
+	userData, err := r.accountClient.DeleteAccount(ctx, email, password)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) SignUp(ctx context.Context, email, password string) ([]byte, *account.SignupResponse, error) {
@@ -1652,7 +1705,11 @@ func (r *LocalBackend) RemoveDevice(ctx context.Context, deviceID string) (*acco
 }
 
 func (r *LocalBackend) OAuthLoginCallback(ctx context.Context, oAuthToken string) (*account.UserData, error) {
-	return r.accountClient.OAuthLoginCallback(ctx, oAuthToken)
+	userData, err := r.accountClient.OAuthLoginCallback(ctx, oAuthToken)
+	if err == nil {
+		r.refreshUserMessages()
+	}
+	return userData, err
 }
 
 func (r *LocalBackend) OAuthLoginURL(ctx context.Context, provider string) (string, error) {
@@ -1671,6 +1728,40 @@ func (r *LocalBackend) UserData() (*account.UserData, error) {
 	return &userData, nil
 }
 
+// CurrentUserMessage returns the current account's pending message.
+func (r *LocalBackend) CurrentUserMessage() (*wire.ResolvedUserMessage, error) {
+	if r.userMessages == nil {
+		return nil, nil
+	}
+	return r.userMessages.Current()
+}
+
+// RefreshUserMessages schedules an immediate eligibility refresh.
+func (r *LocalBackend) RefreshUserMessages() {
+	r.refreshUserMessages()
+}
+
+func (r *LocalBackend) refreshUserMessages() {
+	if r.userMessages != nil {
+		r.userMessages.Refresh()
+	}
+}
+
+// AcknowledgeUserMessage records that the UI displayed displayID.
+func (r *LocalBackend) AcknowledgeUserMessage(displayID string) error {
+	if r.userMessages == nil {
+		return clientmessage.ErrMessageNotPending
+	}
+	return r.userMessages.Acknowledge(displayID)
+}
+
+// SetUserMessageActivity adjusts polling for app and network lifecycle changes.
+func (r *LocalBackend) SetUserMessageActivity(active, online bool) {
+	if r.userMessages != nil {
+		r.userMessages.SetActivity(active, online)
+	}
+}
+
 ///////////////////
 // Subscriptions //
 ///////////////////

go.mod

@@ -40,7 +40,7 @@ require (
 	github.com/alitto/pond v1.9.2
 	github.com/getlantern/amp v0.0.0-20260606002220-a8629924577c
 	github.com/getlantern/broflake v0.0.0-20260810172605-bef5e5234952
-	github.com/getlantern/common v1.2.1-0.20260708083946-cc657b08792c
+	github.com/getlantern/common v1.2.1-0.20260818065623-10c2257aa54f
 	github.com/getlantern/dnstt v0.0.0-20260603191204-3b860502c0ac
 	github.com/getlantern/domainfront v0.0.0-20260722204513-8c1f8acfa715
 	github.com/getlantern/keepcurrent v0.0.0-20260616120552-f204338b01a3
@@ -67,6 +67,7 @@ require (
 	go.opentelemetry.io/otel/sdk v1.43.0
 	go.opentelemetry.io/otel/sdk/metric v1.43.0
 	golang.org/x/term v0.41.0
+	golang.org/x/text v0.35.0
 	golang.zx2c4.com/wireguard/wgctrl v0.0.0-20241231184526-a9ab2273dd10
 	google.golang.org/protobuf v1.36.11
 	gopkg.in/natefinch/lumberjack.v2 v2.2.1

go.sum

@@ -238,8 +238,8 @@ github.com/getlantern/amp v0.0.0-20260606002220-a8629924577c h1:ZzxuhIWO295y4eE6
 github.com/getlantern/amp v0.0.0-20260606002220-a8629924577c/go.mod h1:b5teAOFT+vpBqc2CHoz74QTEM15iOv1PLdQogwXcfrM=
 github.com/getlantern/broflake v0.0.0-20260810172605-bef5e5234952 h1:nD8iJ4IpaTq/09PhoOzmaGTwatOxsR41neSmbCY6RS8=
 github.com/getlantern/broflake v0.0.0-20260810172605-bef5e5234952/go.mod h1:1+1kCIg9Zj+2CgN+vl868AlAZVUItuN4wLhFur5QakA=
-github.com/getlantern/common v1.2.1-0.20260708083946-cc657b08792c h1:Hpxu12ORnAcyYuIqV2yAqrmDAnTaY1Cd3yL7TvFB6ME=
-github.com/getlantern/common v1.2.1-0.20260708083946-cc657b08792c/go.mod h1:eSSuV4bMPgQJnczBw+KWWqWNo1itzmVxC++qUBPRTt0=
+github.com/getlantern/common v1.2.1-0.20260818065623-10c2257aa54f h1:8iZqf4mUkFXKmUnDj2Iej0WySAzLuQmHOX736b4pCYU=
+github.com/getlantern/common v1.2.1-0.20260818065623-10c2257aa54f/go.mod h1:eSSuV4bMPgQJnczBw+KWWqWNo1itzmVxC++qUBPRTt0=
 github.com/getlantern/context v0.0.0-20220418194847-3d5e7a086201 h1:oEZYEpZo28Wdx+5FZo4aU7JFXu0WG/4wJWese5reQSA=
 github.com/getlantern/context v0.0.0-20220418194847-3d5e7a086201/go.mod h1:Y9WZUHEb+mpra02CbQ/QczLUe6f0Dezxaw5DCJlJQGo=
 github.com/getlantern/dnstt v0.0.0-20260603191204-3b860502c0ac h1:TMvkNgLVyIYAfu1dYrOuRPYMVY+cHEo1C0CYWhtSw2A=

ipc/client.go

@@ -16,6 +16,7 @@ import (
 	"syscall"
 	"time"
 
+	wire "github.com/getlantern/common/usermessage"
 	box "github.com/getlantern/lantern-box"
 
 	"github.com/getlantern/radiance/account"
@@ -205,6 +206,35 @@ func (c *Client) UpdateConfig(ctx context.Context) error {
 	return err
 }
 
+// CurrentUserMessage returns the pending message for the current account.
+func (c *Client) CurrentUserMessage(ctx context.Context) (*wire.ResolvedUserMessage, error) {
+	var response CurrentUserMessageResponse
+	if err := c.doJSON(ctx, http.MethodGet, userMessageEndpoint, nil, &response); err != nil {
+		return nil, err
+	}
+	return response.Message, nil
+}
+
+// RefreshUserMessages schedules an immediate server eligibility refresh.
+func (c *Client) RefreshUserMessages(ctx context.Context) error {
+	_, err := c.do(ctx, http.MethodPost, userMessageRefreshEndpoint, nil)
+	return err
+}
+
+// AcknowledgeUserMessage records that the UI displayed displayID.
+func (c *Client) AcknowledgeUserMessage(ctx context.Context, displayID string) error {
+	_, err := c.do(ctx, http.MethodPost, userMessageAcknowledgeEndpoint,
+		UserMessageAcknowledgeRequest{DisplayID: displayID})
+	return err
+}
+
+// SetUserMessageActivity updates the app and connectivity lifecycle used by polling.
+func (c *Client) SetUserMessageActivity(ctx context.Context, active, online bool) error {
+	_, err := c.do(ctx, http.MethodPatch, userMessageActivityEndpoint,
+		UserMessageActivityRequest{Active: active, Online: online})
+	return err
+}
+
 ///////////////////////
 // Server management //
 ///////////////////////

ipc/server.go

@@ -24,6 +24,7 @@ import (
 	rlog "github.com/getlantern/radiance/log"
 	"github.com/getlantern/radiance/peer"
 	"github.com/getlantern/radiance/unbounded"
+	clientmessage "github.com/getlantern/radiance/usermessage"
 	"github.com/getlantern/radiance/vpn"
 
 	sjson "github.com/sagernet/sing/common/json"
@@ -54,6 +55,11 @@ const (
 	configEventsEndpoint = "/config/events"
 	configUpdateEndpoint = "/config/update"
 
+	userMessageEndpoint            = "/user-messages"
+	userMessageRefreshEndpoint     = "/user-messages/refresh"
+	userMessageAcknowledgeEndpoint = "/user-messages/acknowledge"
+	userMessageActivityEndpoint    = "/user-messages/activity"
+
 	// Server management endpoints
 	serversEndpoint              = "/servers"
 	serversAddEndpoint           = "/servers/add"
@@ -229,6 +235,11 @@ func newLocalAPI(b *backend.LocalBackend, withAuth bool) *localapi {
 	mux.HandleFunc("GET "+configEventsEndpoint, s.configEventsHandler)
 	mux.HandleFunc("POST "+configUpdateEndpoint, traced(s.configUpdateHandler))
 
+	mux.HandleFunc("GET "+userMessageEndpoint, traced(s.userMessageHandler))
+	mux.HandleFunc("POST "+userMessageRefreshEndpoint, traced(s.userMessageRefreshHandler))
+	mux.HandleFunc("POST "+userMessageAcknowledgeEndpoint, traced(s.userMessageAcknowledgeHandler))
+	mux.HandleFunc("PATCH "+userMessageActivityEndpoint, traced(s.userMessageActivityHandler))
+
 	// Server management
 	mux.HandleFunc("GET "+serversEndpoint, traced(s.serversHandler))
 	mux.HandleFunc("POST "+serversAddEndpoint, traced(s.serversAddHandler))
@@ -896,6 +907,47 @@ func (s *localapi) settingsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func (s *localapi) userMessageHandler(w http.ResponseWriter, r *http.Request) {
+	message, err := s.backend(r.Context()).CurrentUserMessage()
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusInternalServerError)
+		return
+	}
+	writeJSON(w, http.StatusOK, CurrentUserMessageResponse{Message: message})
+}
+
+func (s *localapi) userMessageRefreshHandler(w http.ResponseWriter, r *http.Request) {
+	s.backend(r.Context()).RefreshUserMessages()
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (s *localapi) userMessageAcknowledgeHandler(w http.ResponseWriter, r *http.Request) {
+	var request UserMessageAcknowledgeRequest
+	if err := decodeJSON(r, &request); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	if err := s.backend(r.Context()).AcknowledgeUserMessage(request.DisplayID); err != nil {
+		status := http.StatusInternalServerError
+		if errors.Is(err, clientmessage.ErrMessageNotPending) {
+			status = http.StatusConflict
+		}
+		http.Error(w, err.Error(), status)
+		return
+	}
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (s *localapi) userMessageActivityHandler(w http.ResponseWriter, r *http.Request) {
+	var request UserMessageActivityRequest
+	if err := decodeJSON(r, &request); err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+		return
+	}
+	s.backend(r.Context()).SetUserMessageActivity(request.Active, request.Online)
+	w.WriteHeader(http.StatusNoContent)
+}
+
 func (s *localapi) envHandler(w http.ResponseWriter, r *http.Request) {
 	switch r.Method {
 	case http.MethodPatch:

ipc/types.go

@@ -2,6 +2,7 @@ package ipc
 
 import (
 	"github.com/getlantern/common"
+	wire "github.com/getlantern/common/usermessage"
 
 	"github.com/getlantern/radiance/account"
 	"github.com/getlantern/radiance/issue"
@@ -116,6 +117,17 @@ type IssueReportRequest struct {
 	Attachments           []*issue.Attachment `json:"attachments"`
 }
 
+// UserMessageAcknowledgeRequest identifies the pending message displayed by the UI.
+type UserMessageAcknowledgeRequest struct {
+	DisplayID string `json:"displayID"`
+}
+
+// UserMessageActivityRequest reports whether foreground polling should run.
+type UserMessageActivityRequest struct {
+	Active bool `json:"active"`
+	Online bool `json:"online"`
+}
+
 // Shared response types used by both client and server.
 
 type SelectedServerResponse struct {
@@ -148,6 +160,11 @@ type PlansResponse struct {
 	Plans string `json:"plans"`
 }
 
+// CurrentUserMessageResponse contains the pending message, if one exists.
+type CurrentUserMessageResponse struct {
+	Message *wire.ResolvedUserMessage `json:"message,omitempty"`
+}
+
 type ResultResponse struct {
 	Result string `json:"result"`
 }