From 7a0a2dc3e5e2e028918db487ce87308a16199b7c Mon Sep 17 00:00:00 2001
From: Lorenz Stechauner <lorenz.stechauner@necronda.net>
Date: Mon, 29 Aug 2022 16:12:31 +0200
Subject: [PATCH] Add Session.genRequestNumDiscriminator()

---
 src/usimp.ts | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/usimp.ts b/src/usimp.ts
index b893887..6c3eaec 100644
--- a/src/usimp.ts
+++ b/src/usimp.ts
@@ -21,7 +21,7 @@ interface DomainServerJson {
 
 interface OutputEnvelopeJson {
     status: string,
-    requestNr: number,
+    request_nr: number,
     data: any,
     action: string | null | undefined,
     error: {
@@ -156,6 +156,7 @@ export class Session {
     httpBaseUrl: string | null;
     websocket: WebSocket | null;
     numRequests: number;
+    requestNumDiscriminator: number;
     subscriptions: {
         callback: (a: EventJson) => void,
         requestNr: number | undefined,
@@ -168,6 +169,7 @@ export class Session {
     constructor(domain: Domain) {
         this.domain = domain;
         this.numRequests = 0;
+        this.requestNumDiscriminator = Session.genRequestNumDiscriminator();
         this.server = null;
         this.token = null;
         this.httpBaseUrl = null;
@@ -176,6 +178,14 @@ export class Session {
         this.subscriptionEndpoints = [];
     }
 
+    private static genRequestNumDiscriminator(): number {
+        // JS uses 64-bit double precision floating point numbers.
+        // These can accurately represent integers up to 53 bit.
+        // In JS bitwise operators only operate on 32-bit integers.
+        // Here a 48-bit integer number is generated.
+        return Math.floor(Math.random() * 0x1000000) * 0x1000000;
+    }
+
     async close(keepEndpoints: boolean = false) {
         await this.unsubscribeAll(keepEndpoints);
         if (this.websocket && (this.websocket.readyState !== WebSocket.CLOSING && this.websocket.readyState !== WebSocket.CLOSED)) {
@@ -303,7 +313,7 @@ export class Session {
         while (true) {
             try {
                 if (!forceHttp && this.websocket !== null) {
-                    const req_nr = this.numRequests;
+                    const req_nr = this.numRequests + this.requestNumDiscriminator;
                     const startTime = performance.now();
 
                     await this.waitForWebSocket(timeout);
@@ -421,7 +431,6 @@ export class Session {
     }
 
     private async _subscribe(cb: (a: EventJson) => void) {
-        this.numRequests++;
         if (this.websocket !== null) {
             const subscription = await this.send('subscribe', {}, 60_000, false, undefined, (res) => {
                 if (res.action === 'push') {