From b4f9302d4c87836ce19ca659dd9ee7ba8b37a93b Mon Sep 17 00:00:00 2001
From: MichaelDvP <github@mdvp.de>
Date: Mon, 10 Jan 2022 08:48:50 +0100
Subject: [PATCH] fix #282, check received status before toggling fetch-flag on
 empty telegrams.

---
 src/emsdevice.cpp | 14 +++++++-------
 src/emsdevice.h   |  4 +++-
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/emsdevice.cpp b/src/emsdevice.cpp
index 55d8698bb..d288c3fc4 100644
--- a/src/emsdevice.cpp
+++ b/src/emsdevice.cpp
@@ -452,7 +452,7 @@ void EMSdevice::show_mqtt_handlers(uuid::console::Shell & shell) {
 
 // register a callback function for a specific telegram type
 void EMSdevice::register_telegram_type(const uint16_t telegram_type_id, const __FlashStringHelper * telegram_type_name, bool fetch, const process_function_p f) {
-    telegram_functions_.emplace_back(telegram_type_id, telegram_type_name, fetch, f);
+    telegram_functions_.emplace_back(telegram_type_id, telegram_type_name, fetch, false, f);
 }
 
 // add to device value library, also know now as a "device entity"
@@ -1339,17 +1339,17 @@ const std::string EMSdevice::telegram_type_name(std::shared_ptr<const Telegram>
 // take a telegram_type_id and call the matching handler
 // return true if match found
 bool EMSdevice::handle_telegram(std::shared_ptr<const Telegram> telegram) {
-    for (const auto & tf : telegram_functions_) {
+    for (auto & tf : telegram_functions_) {
         if (tf.telegram_type_id_ == telegram->type_id) {
-            // if the data block is empty, assume that this telegram is not recognized by the bus master
-            // so remove it from the automatic fetch list
-            if (telegram->message_length == 0 && telegram->offset == 0) {
+            // if the data block is empty and we have not received data before, assume that this telegram
+            // is not recognized by the bus master. So remove it from the automatic fetch list
+            if (telegram->message_length == 0 && telegram->offset == 0 && !tf.received_) {
                 EMSESP::logger().debug(F("This telegram (%s) is not recognized by the EMS bus"), read_flash_string(tf.telegram_type_name_).c_str());
-                toggle_fetch(tf.telegram_type_id_, false);
+                tf.fetch_ = false;
                 return false;
             }
-
             if (telegram->message_length > 0) {
+                tf.received_ = true;
                 tf.process_function_(telegram);
             }
 
diff --git a/src/emsdevice.h b/src/emsdevice.h
index b96d81d6b..5326efa0b 100644
--- a/src/emsdevice.h
+++ b/src/emsdevice.h
@@ -379,12 +379,14 @@ class EMSdevice {
         uint16_t                    telegram_type_id_;   // it's type_id
         const __FlashStringHelper * telegram_type_name_; // e.g. RC20Message
         bool                        fetch_;              // if this type_id be queried automatically
+        bool                        received_;
         process_function_p          process_function_;
 
-        TelegramFunction(uint16_t telegram_type_id, const __FlashStringHelper * telegram_type_name, bool fetch, const process_function_p process_function)
+        TelegramFunction(uint16_t telegram_type_id, const __FlashStringHelper * telegram_type_name, bool fetch, bool received, const process_function_p process_function)
             : telegram_type_id_(telegram_type_id)
             , telegram_type_name_(telegram_type_name)
             , fetch_(fetch)
+            , received_(received)
             , process_function_(process_function) {
         }
     };