mirror of
https://github.com/MeshCore-Beacon/beacon-server.git
synced 2026-09-01 16:48:19 +00:00
245 lines
7.3 KiB
Go
245 lines
7.3 KiB
Go
// Copyright 2026 Beacon Contributors
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// SPDX-License-Identifier: AGPL-3.0-or-later
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// Package ws handles the WebSocket endpoint at GET /ws.
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//
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// Protocol (from design doc):
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//
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// On connect: server sends hello { v:1, type:"hello", serverTime:<ms>, connectionId:"uuid" }
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//
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// Client → Server:
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// subscribe { v, type, id, scope } → server replies subscribed { v, type, id, subscriptionId }
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// unsubscribe { v, type, id, subscriptionId }
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// ping { v, type, id } → server replies pong { v, type, id }
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//
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// Server → Client events (unsolicited):
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// packetObservation, observerStatus, nodeUpdate, channelMessage
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// lagged { v, type, droppedCount, since, lastObservationId }
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// error { v, type, code, message }
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//
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// Idle connections (no ping) closed after 90s.
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// Client should ping every 30s.
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package ws
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import (
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"context"
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"encoding/json"
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"log"
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"net"
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"net/http"
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"strconv"
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"time"
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"github.com/coder/websocket"
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"github.com/google/uuid"
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"github.com/MeshCore-Beacon/beacon-server/internal/api"
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"github.com/MeshCore-Beacon/beacon-server/internal/hub"
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)
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const (
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pingTimeout = 90 * time.Second // server closes connection if no message received within this window
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writeTimeout = 10 * time.Second // TODO: apply per-write deadline once nhooyr supports it cleanly
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)
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// Handler returns an http.HandlerFunc that requires the hub to be injected.
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// Wire it via router.New(h) so the hub is available at startup.
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func Handler(h *hub.Hub, reader api.Reader, maxConnsPerIP int) http.HandlerFunc {
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limiter := newIPLimiter(maxConnsPerIP)
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return func(w http.ResponseWriter, r *http.Request) {
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ip := r.RemoteAddr
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if host, _, err := net.SplitHostPort(ip); err == nil {
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ip = host
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}
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if !limiter.acquire(ip) {
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log.Printf("ws: connection limit reached for IP %s", ip)
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http.Error(w, "too many connections from this IP", http.StatusTooManyRequests)
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return
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}
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defer limiter.release(ip)
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conn, err := websocket.Accept(w, r, nil)
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if err != nil {
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log.Printf("ws: failed to accept connection: %v", err)
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return
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}
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connID := uuid.NewString()
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client := h.NewClient()
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defer h.Remove(client)
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ctx, cancel := context.WithCancel(r.Context())
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defer cancel()
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// Send hello
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hello := map[string]any{
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"v": 1,
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"type": "hello",
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"serverTime": time.Now().UnixMilli(),
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"connectionId": connID,
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}
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helloBytes, _ := json.Marshal(hello)
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log.Printf("ws[%s]: connected, hello: %s", connID, helloBytes)
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err = conn.Write(ctx, websocket.MessageText, helloBytes)
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if err != nil {
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log.Printf("ws[%s]: failed to send hello: %v", connID, err)
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return
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}
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// Write pump: forward hub events to the WS connection.
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go func() {
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for {
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select {
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case evt, ok := <-client.Send:
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if !ok {
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return
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}
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msg := map[string]any{
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"v": 1,
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"type": "event",
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"event": evt.Type,
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"data": json.RawMessage(evt.Payload),
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}
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msgBytes, _ := json.Marshal(msg)
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err = conn.Write(ctx, websocket.MessageText, msgBytes)
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if err != nil {
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log.Printf("ws[%s]: failed to write hub event: %v", connID, err)
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cancel()
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return
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}
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case lag, ok := <-client.LaggedCH():
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if !ok {
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return
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}
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lagged := map[string]any{
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"v": 1,
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"type": "lagged",
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"droppedCount": lag.DroppedCount,
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"since": time.Now().UnixMilli(),
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}
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lagBytes, _ := json.Marshal(lagged)
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if err := conn.Write(ctx, websocket.MessageText, lagBytes); err != nil {
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log.Printf("ws[%s]: failed to write lagged notice: %v", connID, err)
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cancel()
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return
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}
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case <-ctx.Done():
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return
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}
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}
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}()
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// Read pump: handle subscribe / unsubscribe / ping from the client.
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// Drives the idle timeout; any message resets the deadline.
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for {
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readCtx, readCancel := context.WithTimeout(ctx, pingTimeout)
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_, msgBytes, err := conn.Read(readCtx)
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readCancel()
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if err != nil {
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log.Printf("ws[%s]: read error: %v", connID, err)
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return
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}
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handleClientMessage(ctx, client, reader, h, conn, connID, msgBytes)
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}
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}
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}
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// clientMessage is the shape of every client → server message.
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type clientMessage struct {
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V int `json:"v"`
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Type string `json:"type"`
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ID string `json:"id"`
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SubscriptionID string `json:"subscriptionId,omitempty"`
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Scope *subscribeScope `json:"scope,omitempty"`
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}
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// subscribeScope mirrors the scope object in the subscribe message.
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type subscribeScope struct {
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IATAs []string `json:"iatas"`
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RegionIDs []string `json:"regionIds"`
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RegionSlugs []string `json:"regionSlugs"`
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PayloadTypes []uint8 `json:"payloadTypes"`
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RouteTypes []uint8 `json:"routeTypes"`
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ChannelHashes []string `json:"channelHashes"`
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ObserverIDs []string `json:"observerIds"`
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Events []hub.EventType `json:"events"`
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}
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// handleClientMessage dispatches a parsed client message.
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func handleClientMessage(ctx context.Context, client *hub.Client, reader api.Reader, h *hub.Hub, conn *websocket.Conn, connID string, raw []byte) {
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var msg clientMessage
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if err := json.Unmarshal(raw, &msg); err != nil {
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log.Printf("ws[%s]: bad message: %v", connID, err)
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return
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}
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switch msg.Type {
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case "subscribe":
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if msg.Scope == nil {
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return
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}
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iatas := msg.Scope.IATAs
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for _, ridStr := range msg.Scope.RegionIDs {
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rid, err := strconv.ParseInt(ridStr, 10, 32)
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if err != nil {
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log.Printf("ws[%s]: invalid regionId %q, skipping", connID, ridStr)
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continue
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}
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region, err := reader.GetRegion(ctx, int32(rid))
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if err != nil {
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log.Printf("ws[%s]: region %d not found, skipping: %v", connID, rid, err)
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continue
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}
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iatas = append(iatas, region.IATAs...)
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}
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for _, slug := range msg.Scope.RegionSlugs {
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region, err := reader.GetRegionBySlug(ctx, slug)
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if err != nil {
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log.Printf("ws[%s]: region slug %q not found, skipping: %v", connID, slug, err)
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continue
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}
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iatas = append(iatas, region.IATAs...)
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}
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scope := hub.Scope{
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IATAs: iatas,
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PayloadTypes: msg.Scope.PayloadTypes,
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ChannelHashes: msg.Scope.ChannelHashes,
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Events: msg.Scope.Events,
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}
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subID := uuid.NewString()
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h.AddScope(client, subID, scope)
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reply, _ := json.Marshal(map[string]any{
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"v": 1, "type": "subscribed", "id": msg.ID, "subscriptionId": subID,
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})
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log.Printf("ws[%s]: subscribed %s → %s", connID, msg.ID, subID)
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err := conn.Write(ctx, websocket.MessageText, reply)
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if err != nil {
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log.Printf("ws[%s]: failed to send subscribed reply: %v", connID, err)
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}
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case "unsubscribe":
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if msg.SubscriptionID == "" {
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return
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}
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h.RemoveScope(client, msg.SubscriptionID)
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reply, _ := json.Marshal(map[string]any{
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"v": 1, "type": "unsubscribed", "id": msg.ID, "subscriptionId": msg.SubscriptionID,
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})
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log.Printf("ws[%s]: unsubscribed %s", connID, msg.SubscriptionID)
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if err := conn.Write(ctx, websocket.MessageText, reply); err != nil {
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log.Printf("ws[%s]: failed to send unsubscribed reply: %v", connID, err)
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}
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case "ping":
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reply, _ := json.Marshal(map[string]any{"v": 1, "type": "pong", "id": msg.ID})
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err := conn.Write(ctx, websocket.MessageText, reply)
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if err != nil {
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log.Printf("ws[%s]: failed to send pong: %v", connID, err)
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}
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default:
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log.Printf("ws[%s]: unknown message type %q", connID, msg.Type)
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}
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}
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