From bec7e54f7fc56abff2c90ccb66f6bab8f0a49ed5 Mon Sep 17 00:00:00 2001
From: Will Miles <will@willmiles.net>
Date: Sun, 4 Aug 2024 14:02:05 -0400
Subject: [PATCH] Defer web requests if JSON lock contended

Use the web server's queuing mechanism to call us back later.
---
 wled00/json.cpp        | 2 +-
 wled00/set.cpp         | 5 ++++-
 wled00/wled_server.cpp | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/wled00/json.cpp b/wled00/json.cpp
index 5fae9544e..d4f0d7771 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -1060,7 +1060,7 @@ void serveJson(AsyncWebServerRequest* request)
   }
 
   if (!requestJSONBufferLock(17)) {
-    serveJsonError(request, 503, ERR_NOBUF);
+    request->deferResponse();    
     return;
   }
   // releaseJSONBufferLock() will be called when "response" is destroyed (from AsyncWebServer)
diff --git a/wled00/set.cpp b/wled00/set.cpp
index 88249d3c4..c0977f262 100644
--- a/wled00/set.cpp
+++ b/wled00/set.cpp
@@ -628,7 +628,10 @@ void handleSettingsSet(AsyncWebServerRequest *request, byte subPage)
   //USERMODS
   if (subPage == SUBPAGE_UM)
   {
-    if (!requestJSONBufferLock(5)) return;
+    if (!requestJSONBufferLock(5)) {
+      request->deferResponse();
+      return;
+    }
 
     // global I2C & SPI pins
     int8_t hw_sda_pin  = !request->arg(F("SDA")).length() ? -1 : (int)request->arg(F("SDA")).toInt();
diff --git a/wled00/wled_server.cpp b/wled00/wled_server.cpp
index 8768b2b4e..da7fd2a3a 100644
--- a/wled00/wled_server.cpp
+++ b/wled00/wled_server.cpp
@@ -288,7 +288,7 @@ void initServer()
     bool isConfig = false;
 
     if (!requestJSONBufferLock(14)) {
-      serveJsonError(request, 503, ERR_NOBUF);
+      request->deferResponse();
       return;
     }