From 16459b7c160c95902a2e870f463f16df15e327bc Mon Sep 17 00:00:00 2001
From: =?utf8?q?Rapha=C3=ABl=20Jakse?= <raphael.jakse@univ-grenoble-alpes.fr>
Date: Thu, 2 Apr 2020 19:10:07 +0200
Subject: [PATCH] better handling of xhr requests

---
 trivabble.js | 47 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/trivabble.js b/trivabble.js
index 2a8d669..b3ca064 100644
--- a/trivabble.js
+++ b/trivabble.js
@@ -455,6 +455,8 @@
     }
 
     var pollingServer = false;
+    var pollingReady = false;
+    var retriedImmediately = false;
 
     function fatalError(e) {
         console.error(e);
@@ -661,15 +663,21 @@
     }
 
     function send(data) {
-        var xhr = new XMLHttpRequest();
-
-        xhr.open("POST", "/:trivabble", true);
-        xhr.setRequestHeader("Content-Type", "text/plain");
-        xhr.send(JSON.stringify(data));
+        if (!pollingReady && ((data.cmds && data.cmds.length) && data.cmds[0].cmd !== "joinGame")) {
+            send([]);
+            setTimeout(send.bind(null, data), POLLING_DELAY);
+            return;
+        }
 
-        var thisRequestIsPolling = false, currentIndex = 0, expectedLength = 0;
+        var thisRequestIsPolling = false;
+        var currentIndex = 0;
+        var expectedLength = 0;
 
         if (!data.cmds || !data.cmds.length) {
+            if (pollingServer) {
+                return;
+            }
+
             pollingServer = true;
             thisRequestIsPolling = true;
         }
@@ -678,10 +686,19 @@
             blockMove++;
         }
 
+        var xhr = new XMLHttpRequest();
+
+        xhr.open("POST", "/:trivabble", true);
+        xhr.setRequestHeader("Content-Type", "text/plain");
+        xhr.send(JSON.stringify(data));
+
         xhr.onreadystatechange = function () {
             // TODO error handling
 
-            if (xhr.readyState === 3 && thisRequestIsPolling) {
+            if (xhr.readyState === 2 && thisRequestIsPolling) {
+                pollingReady = true;
+            } else if (xhr.readyState === 3 && thisRequestIsPolling) {
+                pollingReady = true;
                 while (true) {
                     if (!expectedLength) {
                         var i = currentIndex;
@@ -717,6 +734,8 @@
                             fatalError(e);
                         }
 
+                        retriedImmediately = false;
+
                         if (msgs instanceof Array) {
                             for (var i = 0; i < msgs.length; i++) {
                                 handleReceivedData(msgs[i]);
@@ -731,7 +750,19 @@
             } else if (xhr.readyState === 4) {
                 if (thisRequestIsPolling) {
                     pollingServer = false;
-                    setTimeout(sendCmds.bind(null, []), POLLING_DELAY);
+                    pollingReady = false;
+
+                    if (retriedImmediately) {
+                        setTimeout(sendCmds.bind(null, []), POLLING_DELAY);
+                    } else {
+                        retriedImmediately = true;
+                        sendCmds([])
+                    }
+                    return;
+                }
+
+                if (xhr.status === 0 || xhr.status >= 300) {
+                    setTimeout(send.bind(null, data), POLLING_DELAY);
                     return;
                 }
 
-- 
2.30.2