From 67ae716c60b95e9f184b14798d366ec8248fcb23 Mon Sep 17 00:00:00 2001
From: Blaz Kristan <blaz@kristan-sp.si>
Date: Tue, 12 Dec 2023 15:45:57 +0100
Subject: [PATCH] JSON HTTP error handling

---
 wled00/const.h         |  3 ++-
 wled00/fcn_declare.h   |  2 +-
 wled00/json.cpp        |  6 +++---
 wled00/wled_server.cpp | 16 ++++++++++++++--
 4 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/wled00/const.h b/wled00/const.h
index e47d57649..ef1b31c01 100644
--- a/wled00/const.h
+++ b/wled00/const.h
@@ -342,8 +342,9 @@
 // WLED Error modes
 #define ERR_NONE         0  // All good :)
 #define ERR_DENIED       1  // Permission denied
-#define ERR_EEP_COMMIT   2  // Could not commit to EEPROM (wrong flash layout?) OBSOLETE
+#define ERR_CONCURRENCY  2  // Conurrency (client active)
 #define ERR_NOBUF        3  // JSON buffer was not released in time, request cannot be handled at this time
+#define ERR_NOT_IMPL     4  // Not implemented
 #define ERR_JSON         9  // JSON parsing failed (input too large?)
 #define ERR_FS_BEGIN    10  // Could not init filesystem (no partition?)
 #define ERR_FS_QUOTA    11  // The FS is full or the maximum file size is reached
diff --git a/wled00/fcn_declare.h b/wled00/fcn_declare.h
index 810626d0c..ec7527269 100644
--- a/wled00/fcn_declare.h
+++ b/wled00/fcn_declare.h
@@ -399,10 +399,10 @@ bool isIp(String str);
 void createEditHandler(bool enable);
 bool captivePortal(AsyncWebServerRequest *request);
 void initServer();
-void serveIndexOrWelcome(AsyncWebServerRequest *request);
 void serveIndex(AsyncWebServerRequest* request);
 String msgProcessor(const String& var);
 void serveMessage(AsyncWebServerRequest* request, uint16_t code, const String& headl, const String& subl="", byte optionT=255);
+void serveJsonError(AsyncWebServerRequest* request, uint16_t code, uint16_t error);
 String dmxProcessor(const String& var);
 void serveSettings(AsyncWebServerRequest* request, bool post = false);
 void serveSettingsJS(AsyncWebServerRequest* request);
diff --git a/wled00/json.cpp b/wled00/json.cpp
index a91404cb2..bf274e3e0 100644
--- a/wled00/json.cpp
+++ b/wled00/json.cpp
@@ -1012,7 +1012,7 @@ static volatile bool servingClient = false;
 void serveJson(AsyncWebServerRequest* request)
 {
   if (servingClient) {
-    request->send(503, "application/json", F("{\"error\":2}")); // ERR_CONCURENCY
+    serveJsonError(request, 503, ERR_CONCURRENCY);
     return;
   }
   servingClient = true;
@@ -1044,13 +1044,13 @@ void serveJson(AsyncWebServerRequest* request)
     return;
   }
   else if (url.length() > 6) { //not just /json
-    request->send(501, "application/json", F("{\"error\":\"Not implemented\"}"));
+    serveJsonError(request, 501, ERR_NOT_IMPL);
     servingClient = false;
     return;
   }
 
   if (!requestJSONBufferLock(17)) {
-    request->send(503, "application/json", F("{\"error\":3}"));
+    serveJsonError(request, 503, ERR_NOBUF);
     servingClient = false;
     return;
   }
diff --git a/wled00/wled_server.cpp b/wled00/wled_server.cpp
index 4dbfa1909..db8eb4a02 100644
--- a/wled00/wled_server.cpp
+++ b/wled00/wled_server.cpp
@@ -183,7 +183,7 @@ void initServer()
     JsonObject root = doc.as<JsonObject>();
     if (error || root.isNull()) {
       releaseJSONBufferLock();
-      request->send(400, "application/json", F("{\"error\":9}")); // ERR_JSON
+      serveJsonError(request, 400, ERR_JSON);
       return;
     }
     if (root.containsKey("pin")) checkSettingsPIN(root["pin"].as<const char*>());
@@ -201,8 +201,8 @@ void initServer()
       verboseResponse = deserializeState(root);
     } else {
       if (!correctPIN && strlen(settingsPIN)>0) {
-        request->send(401, "application/json", F("{\"error\":1}")); // ERR_DENIED
         releaseJSONBufferLock();
+        serveJsonError(request, 401, ERR_DENIED);
         return;
       }
       verboseResponse = deserializeConfig(root); //use verboseResponse to determine whether cfg change should be saved immediately
@@ -509,6 +509,18 @@ void serveMessage(AsyncWebServerRequest* request, uint16_t code, const String& h
 }
 
 
+void serveJsonError(AsyncWebServerRequest* request, uint16_t code, uint16_t error)
+{
+    AsyncJsonResponse *response = new AsyncJsonResponse(64);
+    if (error < ERR_NOT_IMPL) response->addHeader("Retry-After", "1");
+    response->setContentType("application/json");
+    response->setCode(code);
+    JsonObject obj = response->getRoot();
+    obj[F("error")] = error;
+    response->setLength();
+    request->send(response);
+}
+
 #ifdef WLED_ENABLE_DMX
 String dmxProcessor(const String& var)
 {