From fdd9844dc1bb4b81876ed6f144134f34ccc950fb Mon Sep 17 00:00:00 2001
From: dfahlander <david.fahlander@gmail.com>
Date: Wed, 29 May 2024 15:31:13 +0200
Subject: [PATCH] Dexie-cloud addon websocket client-side rate-limits: Decrease
 pause period from 10 to 1 second when more than 10 WebSocket messages per 10
 seconds limit is reached. + simplify the loop + make it confifurable with
 const variables in top of the module. Remove the panic pause of one minute if
 getting into the limit over and over. Instead let it do it but at most 10
 messages per second. If we see this becoming a problem we could enforce a
 limit on the server instead.

---
 .../src/sync/messagesFromServerQueue.ts       | 23 ++++++++-----------
 1 file changed, 9 insertions(+), 14 deletions(-)

diff --git a/addons/dexie-cloud/src/sync/messagesFromServerQueue.ts b/addons/dexie-cloud/src/sync/messagesFromServerQueue.ts
index d95ea5903..3000cb355 100644
--- a/addons/dexie-cloud/src/sync/messagesFromServerQueue.ts
+++ b/addons/dexie-cloud/src/sync/messagesFromServerQueue.ts
@@ -15,6 +15,10 @@ import { updateBaseRevs } from './updateBaseRevs';
 import { getLatestRevisionsPerTable } from './getLatestRevisionsPerTable';
 import { refreshAccessToken } from '../authentication/authenticate';
 
+const LIMIT_NUM_MESSAGES_PER_TIME = 10; // Allow a maximum of 10 messages per...
+const TIME_WINDOW = 10_000;             // ...10 seconds.
+const PAUSE_PERIOD = 1_000;             // Pause for 1 second if reached
+
 export type MessagesFromServerConsumer = ReturnType<
   typeof MessagesFromServerConsumer
 >;
@@ -25,8 +29,7 @@ export function MessagesFromServerConsumer(db: DexieCloudDB) {
   const event = new BehaviorSubject(null);
   let isWorking = false;
 
-  let loopWarning = 0;
-  let loopDetection = [0, 0, 0, 0, 0, 0, 0, 0, 0, Date.now()];
+  let loopDetection = new Array(LIMIT_NUM_MESSAGES_PER_TIME).fill(0);
 
   event.subscribe(async () => {
     if (isWorking) return;
@@ -40,20 +43,12 @@ export function MessagesFromServerConsumer(db: DexieCloudDB) {
       } finally {
         if (
           loopDetection[loopDetection.length - 1] - loopDetection[0] <
-          10000
+          TIME_WINDOW
         ) {
           // Ten loops within 10 seconds. Slow down!
-          if (Date.now() - loopWarning < 5000) {
-            // Last time we did this, we ended up here too. Wait for a minute.
-            console.warn(`Slowing down websocket loop for one minute`);
-            loopWarning = Date.now() + 60000;
-            await new Promise((resolve) => setTimeout(resolve, 60000));
-          } else {
-            // This is a one-time event. Just pause 10 seconds.
-            console.warn(`Slowing down websocket loop for 10 seconds`);
-            loopWarning = Date.now() + 10000;
-            await new Promise((resolve) => setTimeout(resolve, 10000));
-          }
+          // This is a one-time event. Just pause 10 seconds.
+          console.warn(`Slowing down websocket loop for ${PAUSE_PERIOD} milliseconds`);
+          await new Promise((resolve) => setTimeout(resolve, PAUSE_PERIOD));
         }
         isWorking = false;
         readyToServe.next(true);