[overlays] Move replay into own HTTP request

as replaying through the socket takes ages for longer time ranges

Signed-off-by: Knut Ahlers <knut@ahlers.me>

internal/apimodules/overlays/default/eventclient.mjs

@@ -8,6 +8,8 @@
  * @prop {string} [token] - API access token to use to connect to the WebSocket
  */
 
+const HOUR = 3600 * 1000
+
 const initialSocketBackoff = 500
 const maxSocketBackoff = 10000
 const socketBackoffMultiplier = 1.25
@@ -34,6 +36,14 @@ export default class EventClient {
     this.socketBackoff = initialSocketBackoff
 
     this.connect()
+
+    // If reply is enabled and channel is provided, fetch the replay
+    if (this.paramOptionFallback('replay', false) && this.paramOptionFallback('channel')) {
+      this.fetchReplayForChannel(
+        this.paramOptionFallback('channel'),
+        Number(this.paramOptionFallback('maxReplayAge', -1)),
+      )
+    }
   }
 
   /**
@@ -69,18 +79,6 @@ export default class EventClient {
       if (data.type === '_auth') {
         // Special handling for auth confirmation
         this.socketBackoff = initialSocketBackoff
-
-        // Auth was confirmed, request replay if wanted by client
-        if (this.paramOptionFallback('replay', false) && this.paramOptionFallback('channel')) {
-          this.socket.send(JSON.stringify({
-            fields: {
-              channel: this.paramOptionFallback('channel'),
-              maxage: Number(this.paramOptionFallback('maxReplayAge', -1)),
-            },
-            type: '_replay',
-          }))
-        }
-
         return
       }
 
@@ -102,6 +100,38 @@ export default class EventClient {
     }
   }
 
+  /*
+   * Requests past events from the API and feed them through the registered handlers
+   *
+   * @params {string} channel The channel to fetch the events for
+   * @params {number} hours The amount of hours to fetch into the past (-1 = infinite)
+   * @returns {Promise} Can be listened for failures using `.catch`
+   */
+  fetchReplayForChannel(channel, hours = -1) {
+    const params = new URLSearchParams()
+    if (hours > -1) {
+      params.set('since', new Date(new Date().getTime() - hours * HOUR).toISOString())
+    }
+
+    return fetch(`${this.apiBase()}/overlays/events/${encodeURIComponent(channel)}?${params.toString()}`, {
+      headers: {
+        authorization: this.paramOptionFallback('token'),
+      },
+    })
+      .then(resp => resp.json())
+      .then(data => {
+        const handlers = []
+
+        for (const msg of data) {
+          for (const fn of [this.handlers[msg.type], this.handlers._].filter(fn => fn)) {
+            handlers.push(fn(msg.type, msg.fields, new Date(msg.time), msg.is_live))
+          }
+        }
+
+        return Promise.all(handlers)
+      })
+  }
+
   /**
    * Resolves the given key through url hash parameters with fallback to constructor options
    *

internal/apimodules/overlays/overlays.go

@@ -5,10 +5,13 @@ import (
 	"encoding/json"
 	"net/http"
 	"os"
+	"sort"
+	"strings"
 	"sync"
 	"time"
 
 	"github.com/gofrs/uuid"
+	"github.com/gorilla/mux"
 	"github.com/gorilla/websocket"
 	"github.com/pkg/errors"
 	log "github.com/sirupsen/logrus"
@@ -24,8 +27,7 @@ const (
 
 	moduleUUID = "f9ca2b3a-baf6-45ea-a347-c626168665e8"
 
-	msgTypeRequestAuth   = "_auth"
-	msgTypeRequestReplay = "_replay"
+	msgTypeRequestAuth = "_auth"
 )
 
 type (
@@ -49,7 +51,6 @@ var (
 
 	fsStack httpFSStack
 
-	ptrIntMinusOne = func(v int64) *int64 { return &v }(-1)
 	ptrStringEmpty = func(v string) *string { return &v }("")
 
 	store          plugins.StorageManager
@@ -83,6 +84,31 @@ func Register(args plugins.RegistrationArguments) error {
 		ResponseType: plugins.HTTPRouteResponseTypeMultiple,
 	})
 
+	args.RegisterAPIRoute(plugins.HTTPRouteRegistrationArgs{
+		Description: "Fetch past events for the given channel",
+		HandlerFunc: handleEventsReplay,
+		Method:      http.MethodGet,
+		Module:      "overlays",
+		Name:        "Replay",
+		Path:        "/events/{channel}",
+		QueryParams: []plugins.HTTPRouteParamDocumentation{
+			{
+				Description: "ISO / RFC3339 timestamp to fetch the events after",
+				Name:        "since",
+				Required:    false,
+				Type:        "string",
+			},
+		},
+		RequiresWriteAuth: true,
+		ResponseType:      plugins.HTTPRouteResponseTypeJSON,
+		RouteParams: []plugins.HTTPRouteParamDocumentation{
+			{
+				Description: "Channel to fetch the events from",
+				Name:        "channel",
+			},
+		},
+	})
+
 	args.RegisterAPIRoute(plugins.HTTPRouteRegistrationArgs{
 		HandlerFunc:       handleServeOverlayAsset,
 		IsPrefix:          true,
@@ -135,6 +161,33 @@ func Register(args plugins.RegistrationArguments) error {
 	)
 }
 
+func handleEventsReplay(w http.ResponseWriter, r *http.Request) {
+	var (
+		channel = mux.Vars(r)["channel"]
+		msgs    []socketMessage
+		since   = time.Time{}
+	)
+
+	if s, err := time.Parse(time.RFC3339, r.URL.Query().Get("since")); err == nil {
+		since = s
+	}
+
+	for _, msg := range storedObject.GetChannelEvents("#" + strings.TrimLeft(channel, "#")) {
+		if msg.Time.Before(since) {
+			continue
+		}
+
+		msgs = append(msgs, msg)
+	}
+
+	sort.Slice(msgs, func(i, j int) bool { return msgs[i].Time.Before(msgs[j].Time) })
+
+	if err := json.NewEncoder(w).Encode(msgs); err != nil {
+		http.Error(w, errors.Wrap(err, "encoding response").Error(), http.StatusInternalServerError)
+		return
+	}
+}
+
 func handleServeOverlayAsset(w http.ResponseWriter, r *http.Request) {
 	http.StripPrefix("/overlays", http.FileServer(fsStack)).ServeHTTP(w, r)
 }
@@ -245,19 +298,6 @@ func handleSocketSubscription(w http.ResponseWriter, r *http.Request) {
 					Type:   msgTypeRequestAuth,
 				}
 
-			case msgTypeRequestReplay:
-				go func() {
-					maxAge := time.Duration(recvMsg.Fields.MustInt64("maxage", ptrIntMinusOne)) * time.Hour
-					log.Errorf("DEBUG %s %T", maxAge, recvMsg.Fields.Data()["maxage"])
-					for _, msg := range storedObject.GetChannelEvents(recvMsg.Fields.MustString("channel", ptrStringEmpty)) {
-						if maxAge > 0 && time.Since(msg.Time) > maxAge {
-							continue
-						}
-
-						sendMsgC <- msg
-					}
-				}()
-
 			default:
 				logger.WithField("type", recvMsg.Type).Warn("Got unexpected message type from frontend")
 			}