From cc3b311ab045c13b32eda377d92b736179f16cdc Mon Sep 17 00:00:00 2001
From: "Sergio R. Caprile" <scaprile@cesanta.com>
Date: Tue, 20 Dec 2022 16:06:46 -0300
Subject: [PATCH] Fix MQTT server example

---
 examples/mqtt-server/main.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/examples/mqtt-server/main.c b/examples/mqtt-server/main.c
index e2b80ae8..651a696d 100644
--- a/examples/mqtt-server/main.c
+++ b/examples/mqtt-server/main.c
@@ -108,6 +108,12 @@ static void fn(struct mg_connection *c, int ev, void *ev_data, void *fn_data) {
         }
         break;
       }
+      case MQTT_CMD_PINGREQ: {
+        // The server must send a PINGRESP packet in response to a PINGREQ packet [MQTT-3.12.4-1]
+        MG_INFO(("PINGREQ %p -> PINGRESP", c->fd));
+        mg_mqtt_send_header(c, MQTT_CMD_PINGRESP, 0, 0);
+        break;
+      }
     }
   } else if (ev == MG_EV_ACCEPT) {
     // c->is_hexdumping = 1;