Add MQTT module to STM32 pack

mongoose.h

@@ -3412,9 +3412,12 @@ static inline void mg_dash_ev_handler(struct mg_connection *c, int ev,
   }
 }
 
+// Helper forward declarations for Mongoose CMSIS pack modules
 extern struct mg_mgr g_mgr;
 extern void mg_dash_init(struct mg_mgr *);
 extern void mg_dash_poll(struct mg_mgr *);
+extern void mg_mqtt_init(struct mg_mgr *);
+extern void mg_mqtt_poll(struct mg_mgr *);
 // Copyright (c) 2023 Cesanta Software Limited
 // All rights reserved
 

resources/I-CUBE-Mongoose/Cesanta.I-CUBE-Mongoose.pdsc

@@ -2,12 +2,13 @@
 <package schemaVersion="1.7.40" xmlns:xs="http://www.w3.org/2001/XMLSchema-instance" xs:noNamespaceSchemaLocation="PACK.xsd">
   <vendor>Cesanta</vendor>
   <name>I-CUBE-Mongoose</name>
-  <description>Mongoose - TCP/IP stack + TLS + HTTP + WebSocket + MQTT + Firmware OTA</description>
-  <url>https://mongoose.ws/</url>
+  <description>Mongoose - a lightweight networking library providing TCP/IP stack, TLS, HTTP (Embedded Web Server), WebSocket, MQTT, and Firmware OTA updates. Build production-ready web device dashboards and MQTT cloud connectivity without stitching multiple components together.
+  </description>
+  <url>https://mongoose.ws/downloads/stm32pack/</url>
   <license>License.txt</license>
   <supportContact>https://mongoose.ws/contact/</supportContact>
   <releases>
-    <release date="2026-04-22" version="7.21.3">See https://github.com/cesanta/mongoose/releases/tag/7.21</release>
+    <release date="2026-04-24" version="7.21.4">See https://github.com/cesanta/mongoose/releases/tag/7.21</release>
     <release date="2026-04-08" version="7.21.0">See https://github.com/cesanta/mongoose/releases/tag/7.21</release>
     <release date="2024-03-01" version="7.13.0">See https://github.com/cesanta/mongoose/releases/tag/7.13</release>
   </releases>
@@ -21,7 +22,7 @@
     </condition>
   </conditions>
   <components>
-    <component Cclass="Mongoose" Cgroup="Networking Core" Cversion="7.21.3" maxInstances="1">
+    <component Cclass="Mongoose" Cgroup="Networking Core" Cversion="7.21.4" maxInstances="1">
       <description>Networking Core</description>
       <files>
         <file category="header" name="mongoose.h" />
@@ -29,12 +30,18 @@
         <file category="header" name="mongoose_config.h"/>
       </files>
     </component>
-    <component Cclass="Mongoose" Cgroup="Web Device Dashboard" Cversion="7.21.3" condition="MongooseCore" maxInstances="1">
+    <component Cclass="Mongoose" Cgroup="Web Device Dashboard" Cversion="7.21.4" condition="MongooseCore" maxInstances="1">
       <description>Web Device Dashboard</description>
       <files>
         <file category="sourceC" name="mongoose_dashboard.c"/>
         <file category="sourceC" name="dashboard.html.c"/>
       </files>
     </component>
+    <component Cclass="Mongoose" Cgroup="MQTT Client" Cversion="7.21.4" condition="MongooseCore" maxInstances="1">
+      <description>MQTT Client</description>
+      <files>
+        <file category="sourceC" name="mongoose_mqtt.c"/>
+      </files>
+    </component>
   </components>
 </package>

resources/I-CUBE-Mongoose/Makefile

@@ -1,11 +1,10 @@
-VERSION = 7.21.3
+VERSION = 7.21.4
 REPO_ROOT = ../..
 FILES = Cesanta.I-CUBE-Mongoose.pdsc Release_Notes.html mongoose_config.h README.md
 GENERATED = License.txt \
             mongoose.h mongoose.c \
-            mongoose_dashboard.c dashboard.html.c
-        # STM32CubeMX/Cesanta.I-CUBE-Mongoose.$(VERSION)_Configs.xml \
-        # STM32CubeMX/Cesanta.I-CUBE-Mongoose.$(VERSION)_Modes.xml
+            mongoose_dashboard.c dashboard.html.c \
+            mongoose_mqtt.c dashboard.html.c
 
 all: Cesanta.I-CUBE-Mongoose.$(VERSION).pack
 
@@ -27,6 +26,9 @@ Mongoose:
 mongoose_dashboard.c:
 	cp $(REPO_ROOT)/tutorials/device-dashboard/mongoose_dashboard.c $@
 
+mongoose_mqtt.c:
+	cp $(REPO_ROOT)/tutorials/mqtt/mqtt-client/mongoose_mqtt.c $@
+
 dashboard.html.c:
 	make -C $(REPO_ROOT)/tutorials/device-dashboard dashboard.html.c
 	cp $(REPO_ROOT)/tutorials/device-dashboard/dashboard.html.c $@
@@ -37,11 +39,5 @@ mongoose.h: Mongoose
 mongoose.c: Mongoose
 	cp $(REPO_ROOT)/mongoose.c $@
 
-STM32CubeMX/Cesanta.I-CUBE-Mongoose.${VERSION}_Modes.xml:	STM32CubeMX/m.xml
-	sed s,__VERSION__,$(VERSION),g $^ > $@
-
-STM32CubeMX/Cesanta.I-CUBE-Mongoose.${VERSION}_Configs.xml:	STM32CubeMX/c.xml
-	sed s,__VERSION__,$(VERSION),g $^ > $@
-
 clean:
 	rm -rf *.pack STM32CubeMX/*.$(VERSION)_*.xml $(GENERATED)

resources/I-CUBE-Mongoose/README.md

@@ -101,6 +101,8 @@ Hi from Mongoose! Tick 38187
 
 ## Add full device dashboard
 
+Enable "Mongoose Web Device Dashboard" component in CubeMX. Regenerate code.
+
 Remove the hello world server if you added it. Modify your while loop
 to look like this:
 
@@ -119,3 +121,27 @@ while (1)
 
 Rebuild, reflash your board and enjoy the fully functional device dashboard
 that you can tailor to your firmware.
+
+## Add MQTT Client
+
+Enable "Mongoose MQTT Client" component in CubeMX. Regenerate code.
+
+Add MQTT init and poll to your while loop:
+
+```c
+/* USER CODE BEGIN WHILE */
+struct mg_mgr mgr;
+mg_mgr_init(&mgr);
+mg_mqtt_init(&mgr);
+
+while (1)
+{
+  mg_mgr_poll(&mgr, 1);
+  mg_mqtt_poll(&mgr);
+/* USER CODE END WHILE */
+```
+
+Rebuild, reflash your board. This MQTT Client connects to the
+HiveMQ public MQTT broker - see `mongoose_mqtt.c` file for details.
+Also it add a JSON-RPC "ota.update" function via MQTT, so you can
+update your firmware over MQTT, see https://mongoose.ws/mqtt/

src/dash.h

@@ -267,6 +267,9 @@ static inline void mg_dash_ev_handler(struct mg_connection *c, int ev,
   }
 }
 
+// Helper forward declarations for Mongoose CMSIS pack modules
 extern struct mg_mgr g_mgr;
 extern void mg_dash_init(struct mg_mgr *);
 extern void mg_dash_poll(struct mg_mgr *);
+extern void mg_mqtt_init(struct mg_mgr *);
+extern void mg_mqtt_poll(struct mg_mgr *);

tutorials/mqtt/mqtt-client/Makefile

@@ -1,11 +1,11 @@
 PROG ?= example                   # Program we are building
 DELETE = rm -rf                   # Command to remove files
 OUT ?= -o $(PROG)                 # Compiler argument for output file
-SOURCES = main.c mongoose.c  packed_fs.c      # Source code files, packed_fs.c contains ca.pem, which contains CA certs for TLS
+SOURCES = main.c mongoose.c mongoose_mqtt.c packed_fs.c      # Source code files, packed_fs.c contains ca.pem, which contains CA certs for TLS
 CFLAGS = -W -Wall -Wextra -g -I.  # Build options
 
-# Mongoose build options. See https://mongoose.ws/documentation/#build-options
-CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1
+# Mongoose build options. See https://mongoose.ws/docs/getting-started/build-options/
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1 -DMG_TLS=MG_TLS_BUILTIN
 
 ifeq ($(OS),Windows_NT)   # Windows settings. Assume MinGW compiler. To use VC: make CC=cl CFLAGS=/MD OUT=/Feprog.exe
   PROG ?= example.exe           # Use .exe suffix for the binary
@@ -24,9 +24,3 @@ $(PROG): $(SOURCES)       # Build program from sources
 
 clean:                    # Cleanup. Delete built program and all build artifacts
 	$(DELETE) $(PROG) *.o *.obj *.exe *.dSYM mbedtls
-
-# see https://mongoose.ws/tutorials/tls/#how-to-build for TLS build options
-
-mbedtls:                  # Pull and build mbedTLS library
-	git clone --depth 1 -b v2.28.2 https://github.com/mbed-tls/mbedtls $@
-	$(MAKE) -C mbedtls/library

tutorials/mqtt/mqtt-client/main.c

@@ -1,122 +1,19 @@
 // Copyright (c) 2023-2025 Cesanta Software Limited
 // All rights reserved
-//
-// Example MQTT client. It performs the following steps:
-//    1. Connects to the MQTT server specified by `s_url` variable
-//    2. When connected, subscribes to the topic `s_sub_topic`
-//    3. When it receives a message, echoes it back to `s_pub_topic`
-//    4. Timer-based reconnection logic revives the connection when it is down
-//    5. Ping server periodically. When disconnected, a last will is published
-//
-// To enable SSL/TLS, see https://mongoose.ws/tutorials/tls/#how-to-build
 
 #include "mongoose.h"
 
-static const char *s_url = "mqtt://broker.hivemq.com:1883";
-static const char *s_sub_topic = "mg/123/rx";  // Subscribe topic
-static const char *s_pub_topic = "mg/123/tx";  // Publish topic
-static uint8_t s_qos = 1;                      // MQTT QoS
-static struct mg_connection *s_mqtt_conn;      // Client connection
-
-static void subscribe(struct mg_connection *c, struct mg_str topic) {
-  struct mg_mqtt_opts opts = {};
-  memset(&opts, 0, sizeof(opts));
-  opts.topic = topic;
-  opts.qos = s_qos;
-  mg_mqtt_sub(c, &opts);
-  MG_INFO(("%lu SUBSCRIBED to %.*s", c->id, topic.len, topic.buf));
-}
-
-static void publish(struct mg_connection *c, struct mg_str topic,
-                    struct mg_str message) {
-  struct mg_mqtt_opts opts = {};
-  memset(&opts, 0, sizeof(opts));
-  opts.topic = topic;
-  opts.message = message;
-  opts.qos = s_qos;
-  mg_mqtt_pub(c, &opts);
-  MG_INFO(("%lu PUBLISHED %.*s -> %.*s", c->id, topic.len, topic.buf,
-           message.len, message.buf));
-}
-
-static void mqtt_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
-  if (ev == MG_EV_OPEN) {
-    MG_INFO(("%lu CREATED", c->id));
-    // c->is_hexdumping = 1;
-  } else if (ev == MG_EV_CONNECT) {
-    if (c->is_tls) {
-      struct mg_tls_opts opts = {.ca = mg_unpacked("/certs/ca.pem"),
-                                 .name = mg_url_host(s_url)};
-      mg_tls_init(c, &opts);
-    }
-  } else if (ev == MG_EV_ERROR) {
-    // On error, log error message
-    MG_ERROR(("%lu ERROR %s", c->id, (char *) ev_data));
-  } else if (ev == MG_EV_MQTT_OPEN) {
-    // MQTT connect is successful
-    MG_INFO(("%lu CONNECTED to %s", c->id, s_url));
-    subscribe(c, mg_str(s_sub_topic));
-  } else if (ev == MG_EV_MQTT_MSG) {
-    // When we get echo response, print it
-    char response[100];
-    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
-    mg_snprintf(response, sizeof(response), "Got %.*s -> %.*s", mm->topic.len,
-                mm->topic.buf, mm->data.len, mm->data.buf);
-    publish(c, mg_str(s_pub_topic), mg_str(response));
-  } else if (ev == MG_EV_MQTT_CMD) {
-    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
-    if (mm->cmd == MQTT_CMD_PINGREQ) mg_mqtt_pong(c);
-  } else if (ev == MG_EV_CLOSE) {
-    MG_INFO(("%lu CLOSED", c->id));
-    s_mqtt_conn = NULL;  // Mark that we're closed
-  }
-}
-
-// Timer function - recreate client connection if it is closed
-static void timer_fn(void *arg) {
-  if (s_mqtt_conn == NULL) {
-    struct mg_mgr *mgr = (struct mg_mgr *) arg;
-    struct mg_mqtt_opts opts = {.clean = true,
-                                .qos = s_qos,
-                                .topic = mg_str(s_pub_topic),
-                                .keepalive = 5,
-                                .version = 4,
-                                .message = mg_str("bye")};
-    s_mqtt_conn = mg_mqtt_connect(mgr, s_url, &opts, mqtt_ev_handler, NULL);
-  } else {
-    mg_mqtt_ping(s_mqtt_conn);
-  }
-}
-
-int main(int argc, char *argv[]) {
+int main(void) {
   struct mg_mgr mgr;
-  int i;
-
-  // Parse command-line flags
-  for (i = 1; i < argc; i++) {
-    if (strcmp(argv[i], "-u") == 0 && argv[i + 1] != NULL) {
-      s_url = argv[++i];
-    } else if (strcmp(argv[i], "-p") == 0 && argv[i + 1] != NULL) {
-      s_pub_topic = argv[++i];
-    } else if (strcmp(argv[i], "-s") == 0 && argv[i + 1] != NULL) {
-      s_sub_topic = argv[++i];
-    } else if (strcmp(argv[i], "-v") == 0 && argv[i + 1] != NULL) {
-      mg_log_set(atoi(argv[++i]));
-    } else {
-      MG_ERROR(("Unknown option: %s. Usage:", argv[i]));
-      MG_ERROR(
-          ("%s [-u mqtts://SERVER:PORT] [-p PUB_TOPIC] [-s SUB_TOPIC] "
-           "[-v DEBUG_LEVEL]",
-           argv[0], argv[i]));
-      return 1;
-    }
-  }
 
   mg_mgr_init(&mgr);
-  mg_timer_add(&mgr, 3000, MG_TIMER_REPEAT | MG_TIMER_RUN_NOW, timer_fn, &mgr);
+  mg_mqtt_init(&mgr);
+
   for (;;) {
-    mg_mgr_poll(&mgr, 1000);
+    mg_mgr_poll(&mgr, 100);
+    mg_mqtt_poll(&mgr);
   }
+
   mg_mgr_free(&mgr);
 
   return 0;

tutorials/mqtt/mqtt-client/mongoose_mqtt.c

@@ -0,0 +1,123 @@
+// Copyright (c) 2026 Cesanta Software Limited
+// All rights reserved
+//
+// Example MQTT client. It performs the following steps:
+//    1. Connects to the MQTT server specified by MQTT_SERVER_URL
+//    2. When connected, subscribes to the topic MQTT_SUBSCRIBE_TOPIC
+//    3. When it receives a message, echoes it back to MQTT_PUBLISH_TOPIC
+//    4. Timer-based reconnection logic revives the connection when it is down
+//    5. Ping server periodically. When disconnected, a last will is published
+//    6. Implements "ota.update" for OTA updates, see https://mongoose.ws/mqtt/
+
+#include "mongoose.h"
+
+#define MQTT_SERVER_URL "mqtt://broker.hivemq.com:1883"
+#define MQTT_PUBLISH_TOPIC "mg/123/tx"
+#define MQTT_SUBSCRIBE_TOPIC "mg/123/rx"
+#define MQTT_QOS 1
+#define RECONNECT_PERIOD_MS 3000
+
+static struct mg_connection *s_mqtt_conn;  // Client connection
+static struct mg_rpc *s_rpc = NULL;        // List of registered RPC methods
+
+static void subscribe(struct mg_connection *c, struct mg_str topic) {
+  struct mg_mqtt_opts opts = {};
+  memset(&opts, 0, sizeof(opts));
+  opts.topic = topic;
+  opts.qos = MQTT_QOS;
+  mg_mqtt_sub(c, &opts);
+  MG_DEBUG(("%lu SUBSCRIBED to %.*s", c->id, topic.len, topic.buf));
+}
+
+static void publish(struct mg_connection *c, struct mg_str topic,
+                    struct mg_str message) {
+  struct mg_mqtt_opts opts = {};
+  memset(&opts, 0, sizeof(opts));
+  opts.topic = topic;
+  opts.message = message;
+  opts.qos = MQTT_QOS;
+  mg_mqtt_pub(c, &opts);
+  MG_DEBUG(("%lu PUBLISHED %.*s -> %.*s", c->id, topic.len, topic.buf,
+            message.len, message.buf));
+}
+
+static void rpc_ota_update(struct mg_rpc_req *r) {
+  long ofs = mg_json_get_long(r->frame, "$.params.offset", -1);
+  long tot = mg_json_get_long(r->frame, "$.params.total", -1);
+  int len = 0;
+  char *buf = mg_json_get_b64(r->frame, "$.params.chunk", &len);
+  if (buf == NULL) {
+    mg_rpc_err(r, 1, "%m", MG_ESC("Chunk decoding error"));
+  } else if (ofs < 0 || tot < 0) {
+    mg_rpc_err(r, 1, "%m", MG_ESC("offset and total not set"));
+  } else if (ofs == 0 && mg_ota_begin((size_t) tot) == false) {
+    mg_rpc_err(r, 1, "\"mg_ota_begin(%ld) failed\"", tot);
+  } else if (len > 0 && mg_ota_write(buf, len) == false) {
+    mg_rpc_err(r, 1, "\"mg_ota_write(%lu) @%ld failed\"", len, ofs);
+    mg_ota_end();
+  } else if (len == 0 && mg_ota_end() == false) {
+    mg_rpc_err(r, 1, "\"mg_ota_end() failed\"", tot);
+  } else {
+    mg_rpc_ok(r, "%m", MG_ESC("ok"));
+  }
+  mg_free(buf);
+}
+
+static void mqtt_ev_handler(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_OPEN) {
+    MG_DEBUG(("%lu CREATED, %s", c->id, ev_data));
+    // c->is_hexdumping = 1;
+  } else if (ev == MG_EV_CONNECT) {
+    if (c->is_tls) {
+      struct mg_tls_opts opts = {.ca = mg_unpacked("/certs/ca.pem"),
+                                 .name = mg_url_host(MQTT_SERVER_URL)};
+      mg_tls_init(c, &opts);
+    }
+  } else if (ev == MG_EV_ERROR) {
+    // On error, log error message
+    MG_ERROR(("%lu ERROR %s", c->id, (char *) ev_data));
+  } else if (ev == MG_EV_MQTT_OPEN) {
+    // MQTT connect is successful
+    MG_DEBUG(("%lu CONNECTED to %s", c->id, MQTT_SERVER_URL));
+    subscribe(c, mg_str(MQTT_SUBSCRIBE_TOPIC));
+  } else if (ev == MG_EV_MQTT_MSG) {
+    // When we get echo response, print it
+    char response[100];
+    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
+    mg_snprintf(response, sizeof(response), "Got %.*s -> %.*s", mm->topic.len,
+                mm->topic.buf, mm->data.len, mm->data.buf);
+    publish(c, mg_str(MQTT_PUBLISH_TOPIC), mg_str(response));
+  } else if (ev == MG_EV_MQTT_CMD) {
+    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
+    if (mm->cmd == MQTT_CMD_PINGREQ) mg_mqtt_pong(c);
+  } else if (ev == MG_EV_CLOSE) {
+    MG_ERROR(("%lu CLOSED", c->id));
+    s_mqtt_conn = NULL;  // Mark that we're closed
+  }
+}
+
+void mg_mqtt_init(struct mg_mgr *mgr) {
+  (void) mgr;
+  if (!s_rpc) mg_rpc_add(&s_rpc, mg_str("ota.update"), rpc_ota_update, NULL);
+}
+
+void mg_mqtt_poll(struct mg_mgr *mgr) {
+  static uint64_t timer = 1;  // 1 triggers expiration on first poll
+
+  // Reconnect if connection is closed, and send MQTT PINGs to keep
+  // the connection alive or to detect connection loss
+  if (mg_timer_expired(&timer, RECONNECT_PERIOD_MS, mg_now())) {
+    if (s_mqtt_conn == NULL) {
+      struct mg_mqtt_opts opts = {.clean = true,
+                                  .qos = MQTT_QOS,
+                                  .topic = mg_str(MQTT_PUBLISH_TOPIC),
+                                  .keepalive = 5,
+                                  .version = 4,
+                                  .message = mg_str("bye")};
+      s_mqtt_conn =
+          mg_mqtt_connect(mgr, MQTT_SERVER_URL, &opts, mqtt_ev_handler, NULL);
+    } else {
+      mg_mqtt_ping(s_mqtt_conn);
+    }
+  }
+}