move to new skeleton

tutorials/mqtt/mqtt-client-aws-iot/Makefile

@@ -0,0 +1,32 @@
+PROG ?= example                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+OUT ?= -o $(PROG)                 # Compiler argument for output file
+SOURCES = main.c mongoose.c  packed_fs.c      # Source code files, packed_fs.c contains ca.pem, which contains CA certs for TLS
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1 -DMG_ENABLE_PACKED_FS=1
+
+ifeq ($(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
+  CC = gcc                      # Use MinGW gcc compiler
+  CFLAGS += -lws2_32            # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S  # Command prompt command to delete files
+  OUT ?= -o $(PROG)             # Build output
+  MAKE += WINDOWS=1 CC=$(CC)
+endif
+
+all: $(PROG)              # Default target. Build and run program
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): $(SOURCES)       # Build program from sources
+	$(CC) $(SOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(OUT)
+
+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-aws-iot/README.md

@@ -0,0 +1,2 @@
+- This example requires generating AWS and user credentials and downloading certificates
+- This example requires building with TLS support; before running, see detailed tutorial at https://mongoose.ws/tutorials/mqtt/mqtt-client-aws-iot/

tutorials/mqtt/mqtt-client-aws-iot/main.c

@@ -0,0 +1,101 @@
+// Copyright (c) 2020 Cesanta Software Limited
+// All rights reserved
+//
+// Example MQTT client. It performs the following steps:
+//    1. Connects to the AWS IoT MQTT server
+//    2. When connected, subscribes to the topic `s_rx_topic`
+//    3. Publishes message `hello` to the `s_tx_topic` periodically
+//
+// This example requires TLS support. By default, it is built with mbedTLS,
+// therefore make sure mbedTLS is installed. To build with OpenSSL, execute:
+//    make clean all CFLAGS="-W -Wall -DMG_ENABLE_OPENSSL=1 -lssl"
+
+// In order to get MQTT URL, login to AWS IoT, click on "Settings" on the left
+// bar, copy the "Endpoint" URL.
+static const char *s_url =
+    "mqtts://a1pjwh2bop1ojt-ats.iot.eu-west-1.amazonaws.com";
+
+// To create certificates:
+// 1. Click Policies -> Create, fill fields:
+//               Name        : Policy1
+//               Action      : iot:*
+//               Resource ARN: *
+//               Effect      : allow
+//        then, click "Create"
+// 2. Click Manage -> Things -> Create things -> Create single thing -> Next
+//      Thing name: t1, no shadow, Next
+//      Auto-generate new certificate, Next
+//      Select policy Policy1, Create thing
+// 3. From the dialog box that appears, download:
+//      xxx-certificate.pem.crt as cert.pem to the example directory
+//      xxx-private.pem.key as key.pem to the example directory
+// static const char *s_cert = "cert.pem";
+// static const char *s_key = "key.pem";
+
+static const char *s_rx_topic = "d/rx";
+static const char *s_tx_topic = "d/tx";
+static int s_qos = 1;
+
+#include "mongoose.h"
+
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_OPEN) {
+    // c->is_hexdumping = 1;
+  } else if (ev == MG_EV_CONNECT) {
+    if (mg_url_is_ssl(s_url)) {
+      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(("%p %s", c->fd, (char *) ev_data));
+  } else if (ev == MG_EV_MQTT_OPEN) {
+    // MQTT connect is successful
+    struct mg_str topic = mg_str(s_rx_topic);
+    MG_INFO(("Connected to %s", s_url));
+    MG_INFO(("Subscribing to %s", s_rx_topic));
+    struct mg_mqtt_opts sub_opts;
+    memset(&sub_opts, 0, sizeof(sub_opts));
+    sub_opts.topic = topic;
+    sub_opts.qos = s_qos;
+    mg_mqtt_sub(c, &sub_opts);
+    c->data[0] = 'X';  // Set a label that we're logged in
+  } else if (ev == MG_EV_MQTT_MSG) {
+    // When we receive MQTT message, print it
+    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
+    MG_INFO(("Received on %.*s : %.*s", (int) mm->topic.len, mm->topic.buf,
+             (int) mm->data.len, mm->data.buf));
+  } else if (ev == MG_EV_POLL && c->data[0] == 'X') {
+    static unsigned long prev_second;
+    unsigned long now_second = (*(unsigned long *) ev_data) / 1000;
+    if (now_second != prev_second) {
+      struct mg_str topic = mg_str(s_tx_topic), data = mg_str("{\"a\":123}");
+      MG_INFO(("Publishing to %s", s_tx_topic));
+      struct mg_mqtt_opts pub_opts;
+      memset(&pub_opts, 0, sizeof(pub_opts));
+      pub_opts.topic = topic;
+      pub_opts.message = data;
+      pub_opts.qos = s_qos, pub_opts.retain = false;
+      mg_mqtt_pub(c, &pub_opts);
+      prev_second = now_second;
+    }
+  }
+
+  if (ev == MG_EV_ERROR || ev == MG_EV_CLOSE) {
+    MG_INFO(("Got event %d, stopping...", ev));
+    *(bool *) c->fn_data = true;  // Signal that we're done
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;
+  struct mg_mqtt_opts opts = {.clean = true};
+  bool done = false;
+  mg_mgr_init(&mgr);                               // Initialise event manager
+  MG_INFO(("Connecting to %s", s_url));            // Inform that we're starting
+  mg_mqtt_connect(&mgr, s_url, &opts, fn, &done);  // Create client connection
+  while (!done) mg_mgr_poll(&mgr, 1000);           // Loop until done
+  mg_mgr_free(&mgr);                               // Finished, cleanup
+  return 0;
+}

tutorials/mqtt/mqtt-client-aws-iot/mongoose.c

@@ -0,0 +1 @@
+../../../mongoose.c

tutorials/mqtt/mqtt-client-aws-iot/mongoose.h

@@ -0,0 +1 @@
+../../../mongoose.h

tutorials/mqtt/mqtt-client-aws-iot/packed_fs.c

@@ -0,0 +1 @@
+../../http/http-client/packed_fs.c

tutorials/mqtt/mqtt-client/Makefile

@@ -0,0 +1,32 @@
+PROG ?= example                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+OUT ?= -o $(PROG)                 # Compiler argument for output file
+SOURCES = main.c mongoose.c  packed_fs.c      # Source code files, packed_fs.c contains ca.pem, which contains CA certs for TLS
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1 -DMG_ENABLE_PACKED_FS=1
+
+ifeq ($(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
+  CC = gcc                      # Use MinGW gcc compiler
+  CFLAGS += -lws2_32            # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S  # Command prompt command to delete files
+  OUT ?= -o $(PROG)             # Build output
+  MAKE += WINDOWS=1 CC=$(CC)
+endif
+
+all: $(PROG)              # Default target. Build and run program
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): $(SOURCES)       # Build program from sources
+	$(CC) $(SOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(OUT)
+
+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/README.md

@@ -0,0 +1 @@
+See detailed tutorial at https://mongoose.ws/tutorials/mqtt/mqtt-client/

tutorials/mqtt/mqtt-client/main.c

@@ -0,0 +1,114 @@
+// Copyright (c) 2023 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. Publishes message `hello` to the `s_pub_topic`
+//    4. Receives that message back from the subscribed topic and closes
+//    5. Timer-based reconnection logic revives the connection when it is down
+//
+// 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/+/test";     // Publish topic
+static const char *s_pub_topic = "mg/clnt/test";  // Subscribe topic
+static int s_qos = 1;                             // MQTT QoS
+static struct mg_connection *s_conn;              // Client connection
+
+// Handle interrupts, like Ctrl-C
+static int s_signo;
+static void signal_handler(int signo) {
+  s_signo = signo;
+}
+
+static void fn(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 (mg_url_is_ssl(s_url)) {
+      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
+    struct mg_str subt = mg_str(s_sub_topic);
+    struct mg_str pubt = mg_str(s_pub_topic), data = mg_str("hello");
+    MG_INFO(("%lu CONNECTED to %s", c->id, s_url));
+    struct mg_mqtt_opts sub_opts;
+    memset(&sub_opts, 0, sizeof(sub_opts));
+    sub_opts.topic = subt;
+    sub_opts.qos = s_qos;
+    mg_mqtt_sub(c, &sub_opts);
+    MG_INFO(("%lu SUBSCRIBED to %.*s", c->id, (int) subt.len, subt.buf));
+    struct mg_mqtt_opts pub_opts;
+    memset(&pub_opts, 0, sizeof(pub_opts));
+    pub_opts.topic = pubt;
+    pub_opts.message = data;
+    pub_opts.qos = s_qos, pub_opts.retain = false;
+    mg_mqtt_pub(c, &pub_opts);
+    MG_INFO(("%lu PUBLISHED %.*s -> %.*s", c->id, (int) data.len, data.buf,
+             (int) pubt.len, pubt.buf));
+  } else if (ev == MG_EV_MQTT_MSG) {
+    // When we get echo response, print it
+    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
+    MG_INFO(("%lu RECEIVED %.*s <- %.*s", c->id, (int) mm->data.len,
+             mm->data.buf, (int) mm->topic.len, mm->topic.buf));
+  } else if (ev == MG_EV_CLOSE) {
+    MG_INFO(("%lu CLOSED", c->id));
+    s_conn = NULL;  // Mark that we're closed
+  }
+}
+
+// Timer function - recreate client connection if it is closed
+static void timer_fn(void *arg) {
+  struct mg_mgr *mgr = (struct mg_mgr *) arg;
+  struct mg_mqtt_opts opts = {.clean = true,
+                              .qos = s_qos,
+                              .topic = mg_str(s_pub_topic),
+                              .version = 4,
+                              .message = mg_str("bye")};
+  if (s_conn == NULL) s_conn = mg_mqtt_connect(mgr, s_url, &opts, fn, NULL);
+}
+
+int main(int argc, char *argv[]) {
+  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;
+    }
+  }
+
+  signal(SIGINT, signal_handler);   // Setup signal handlers - exist event
+  signal(SIGTERM, signal_handler);  // manager loop on SIGINT and SIGTERM
+
+  mg_mgr_init(&mgr);
+  mg_timer_add(&mgr, 3000, MG_TIMER_REPEAT | MG_TIMER_RUN_NOW, timer_fn, &mgr);
+  while (s_signo == 0) mg_mgr_poll(&mgr, 1000);  // Event loop, 1s timeout
+  mg_mgr_free(&mgr);                             // Finished, cleanup
+
+  return 0;
+}

tutorials/mqtt/mqtt-client/mongoose.c

@@ -0,0 +1 @@
+../../../mongoose.c

tutorials/mqtt/mqtt-client/mongoose.h

@@ -0,0 +1 @@
+../../../mongoose.h

tutorials/mqtt/mqtt-client/packed_fs.c

@@ -0,0 +1 @@
+../../http/http-client/packed_fs.c

tutorials/mqtt/mqtt-over-ws-client/Makefile

@@ -0,0 +1,32 @@
+PROG ?= example                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+OUT ?= -o $(PROG)                 # Compiler argument for output file
+SOURCES = main.c mongoose.c  packed_fs.c      # Source code files, packed_fs.c contains ca.pem, which contains CA certs for TLS
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES=1 -DMG_ENABLE_PACKED_FS=1
+
+ifeq ($(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
+  CC = gcc                      # Use MinGW gcc compiler
+  CFLAGS += -lws2_32            # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S  # Command prompt command to delete files
+  OUT ?= -o $(PROG)             # Build output
+  MAKE += WINDOWS=1 CC=$(CC)
+endif
+
+all: $(PROG)              # Default target. Build and run program
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): $(SOURCES)       # Build program from sources
+	$(CC) $(SOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(OUT)
+
+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-over-ws-client/README.md

@@ -0,0 +1 @@
+See detailed tutorial at https://mongoose.ws/tutorials/mqtt/mqtt-over-ws-client/

tutorials/mqtt/mqtt-over-ws-client/main.c

@@ -0,0 +1,106 @@
+// Copyright (c) 2020 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_topic`
+//    3. Publishes message `hello` to the `s_topic`
+//    4. Receives that message back from the subscribed topic and exits
+//
+// To enable SSL/TLS, see https://mongoose.ws/tutorials/tls/#how-to-build
+
+#include "mongoose.h"
+
+static const char *s_url =
+#if MG_TLS
+    "wss://broker.hivemq.com:8884/mqtt";
+#else
+    "ws://broker.hivemq.com:8000/mqtt";
+#endif
+
+static const char *s_topic = "mg/test";
+
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_ERROR) {
+    // On error, log error message
+    MG_ERROR(("%p %s", c->fd, (char *) ev_data));
+  } else if (ev == MG_EV_CONNECT) {
+    if (mg_url_is_ssl(s_url)) {
+      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_WS_OPEN) {
+    // WS connection established. Perform MQTT login
+    MG_INFO(("Connected to WS. Logging in to MQTT..."));
+    struct mg_mqtt_opts opts = {
+        .qos = 1, .topic = mg_str(s_topic), .message = mg_str("goodbye")};
+    size_t len = c->send.len;
+    mg_mqtt_login(c, &opts);
+    mg_ws_wrap(c, c->send.len - len, WEBSOCKET_OP_BINARY);
+    c->is_hexdumping = 1;
+  } else if (ev == MG_EV_WS_MSG) {
+    struct mg_mqtt_message mm;
+    struct mg_ws_message *wm = (struct mg_ws_message *) ev_data;
+    uint8_t version = c->is_mqtt5 ? 5 : 4;
+    MG_INFO(("GOT %d bytes WS msg", (int) wm->data.len));
+    while ((mg_mqtt_parse((uint8_t *) wm->data.buf, wm->data.len, version,
+                          &mm)) == MQTT_OK) {
+      switch (mm.cmd) {
+        case MQTT_CMD_CONNACK:
+          mg_call(c, MG_EV_MQTT_OPEN, &mm.ack);
+          if (mm.ack == 0) {
+            struct mg_str topic = mg_str(s_topic), data = mg_str("hello");
+            size_t len = c->send.len;
+            MG_INFO(("CONNECTED to %s", s_url));
+            struct mg_mqtt_opts sub_opts;
+            memset(&sub_opts, 0, sizeof(sub_opts));
+            sub_opts.topic = topic;
+            sub_opts.qos = 1;
+            mg_mqtt_sub(c, &sub_opts);
+            len = mg_ws_wrap(c, c->send.len - len, WEBSOCKET_OP_BINARY);
+            MG_INFO(("SUBSCRIBED to %.*s", (int) topic.len, topic.buf));
+            struct mg_mqtt_opts pub_opts;
+            memset(&pub_opts, 0, sizeof(pub_opts));
+            pub_opts.topic = topic;
+            pub_opts.message = data;
+            pub_opts.qos = 1, pub_opts.retain = false;
+            mg_mqtt_pub(c, &pub_opts);
+            MG_INFO(("PUBLISHED %.*s -> %.*s", (int) data.len, data.buf,
+                     (int) topic.len, topic.buf));
+            len = mg_ws_wrap(c, c->send.len - len, WEBSOCKET_OP_BINARY);
+          } else {
+            MG_ERROR(("%lu MQTT auth failed, code %d", c->id, mm.ack));
+            c->is_draining = 1;
+          }
+          break;
+        case MQTT_CMD_PUBLISH: {
+          MG_DEBUG(("%lu [%.*s] -> [%.*s]", c->id, (int) mm.topic.len,
+                    mm.topic.buf, (int) mm.data.len, mm.data.buf));
+          MG_INFO(("RECEIVED %.*s <- %.*s", (int) mm.data.len, mm.data.buf,
+                   (int) mm.topic.len, mm.topic.buf));
+          c->is_draining = 1;
+          break;
+        }
+      }
+      wm->data.buf += mm.dgram.len;
+      wm->data.len -= mm.dgram.len;
+    }
+  }
+
+  if (ev == MG_EV_ERROR || ev == MG_EV_CLOSE) {
+    *(bool *) c->fn_data = true;  // Signal that we're done
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;        // Event manager
+  bool done = false;        // Event handler flips it to true when done
+  mg_mgr_init(&mgr);        // Initialise event manager
+  mg_log_set(MG_LL_DEBUG);  // Set log level
+  mg_ws_connect(&mgr, s_url, fn, &done, "%s",  // Create client connection
+                "Sec-Websocket-Protocol: mqtt\r\n");  // Request MQTT protocol
+  while (done == false) mg_mgr_poll(&mgr, 1000);      // Event loop
+  mg_mgr_free(&mgr);                                  // Finished, cleanup
+  return 0;
+}

tutorials/mqtt/mqtt-over-ws-client/mongoose.c

@@ -0,0 +1 @@
+../../../mongoose.c

tutorials/mqtt/mqtt-over-ws-client/mongoose.h

@@ -0,0 +1 @@
+../../../mongoose.h

tutorials/mqtt/mqtt-over-ws-client/packed_fs.c

@@ -0,0 +1 @@
+../../http/http-client/packed_fs.c

tutorials/mqtt/mqtt-server/Makefile

@@ -0,0 +1,25 @@
+PROG ?= example                   # Program we are building
+DELETE = rm -rf                   # Command to remove files
+OUT ?= -o $(PROG)                 # Compiler argument for output file
+SOURCES = main.c mongoose.c       # Source code files
+CFLAGS = -W -Wall -Wextra -g -I.  # Build options
+
+# Mongoose build options. See https://mongoose.ws/documentation/#build-options
+CFLAGS_MONGOOSE += -DMG_ENABLE_LINES
+
+ifeq ($(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
+  CC = gcc                      # Use MinGW gcc compiler
+  CFLAGS += -lws2_32            # Link against Winsock library
+  DELETE = cmd /C del /Q /F /S  # Command prompt command to delete files
+  OUT ?= -o $(PROG)             # Build output
+endif
+
+all: $(PROG)              # Default target. Build and run program
+	$(RUN) ./$(PROG) $(ARGS)
+
+$(PROG): $(SOURCES)       # Build program from sources
+	$(CC) $(SOURCES) $(CFLAGS) $(CFLAGS_MONGOOSE) $(CFLAGS_EXTRA) $(OUT)
+
+clean:                    # Cleanup. Delete built program and all build artifacts
+	$(DELETE) $(PROG) *.o *.obj *.exe *.dSYM

tutorials/mqtt/mqtt-server/README.md

@@ -0,0 +1 @@
+See detailed tutorial at https://mongoose.ws/tutorials/mqtt/mqtt-server/

tutorials/mqtt/mqtt-server/main.c

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+// Copyright (c) 2020 Cesanta Software Limited
+// All rights reserved
+//
+// Example MQTT server. Usage:
+//  1. Start this server, type `make`
+//  2. Install mosquitto MQTT client
+//  3. In one terminal, run:   mosquitto_sub -h localhost -t foo -t bar
+//  4. In another, run:        mosquitto_pub -h localhost -t foo -m hi
+
+#include "mongoose.h"
+
+static const char *s_listen_on = "mqtt://0.0.0.0:1883";
+
+// A list of subscription, held in memory
+struct sub {
+  struct sub *next;
+  struct mg_connection *c;
+  struct mg_str topic;
+  uint8_t qos;
+};
+static struct sub *s_subs = NULL;
+
+// Handle interrupts, like Ctrl-C
+static int s_signo;
+static void signal_handler(int signo) {
+  s_signo = signo;
+}
+
+static size_t mg_mqtt_next_topic(struct mg_mqtt_message *msg,
+                                 struct mg_str *topic, uint8_t *qos,
+                                 size_t pos) {
+  unsigned char *buf = (unsigned char *) msg->dgram.buf + pos;
+  size_t new_pos;
+  if (pos >= msg->dgram.len) return 0;
+
+  topic->len = (size_t) (((unsigned) buf[0]) << 8 | buf[1]);
+  topic->buf = (char *) buf + 2;
+  new_pos = pos + 2 + topic->len + (qos == NULL ? 0 : 1);
+  if ((size_t) new_pos > msg->dgram.len) return 0;
+  if (qos != NULL) *qos = buf[2 + topic->len];
+  return new_pos;
+}
+
+size_t mg_mqtt_next_sub(struct mg_mqtt_message *msg, struct mg_str *topic,
+                        uint8_t *qos, size_t pos) {
+  uint8_t tmp;
+  return mg_mqtt_next_topic(msg, topic, qos == NULL ? &tmp : qos, pos);
+}
+
+size_t mg_mqtt_next_unsub(struct mg_mqtt_message *msg, struct mg_str *topic,
+                          size_t pos) {
+  return mg_mqtt_next_topic(msg, topic, NULL, pos);
+}
+
+// Event handler function
+static void fn(struct mg_connection *c, int ev, void *ev_data) {
+  if (ev == MG_EV_MQTT_CMD) {
+    struct mg_mqtt_message *mm = (struct mg_mqtt_message *) ev_data;
+    MG_DEBUG(("cmd %d qos %d", mm->cmd, mm->qos));
+    switch (mm->cmd) {
+      case MQTT_CMD_CONNECT: {
+        // Client connects
+        if (mm->dgram.len < 9) {
+          mg_error(c, "Malformed MQTT frame");
+        } else if (mm->dgram.buf[8] != 4) {
+          mg_error(c, "Unsupported MQTT version %d", mm->dgram.buf[8]);
+        } else {
+          uint8_t response[] = {0, 0};
+          mg_mqtt_send_header(c, MQTT_CMD_CONNACK, 0, sizeof(response));
+          mg_send(c, response, sizeof(response));
+        }
+        break;
+      }
+      case MQTT_CMD_SUBSCRIBE: {
+        // Client subscribes
+        size_t pos = 4;  // Initial topic offset, where ID ends
+        uint8_t qos, resp[256];
+        struct mg_str topic;
+        int num_topics = 0;
+        while ((pos = mg_mqtt_next_sub(mm, &topic, &qos, pos)) > 0) {
+          struct sub *sub = calloc(1, sizeof(*sub));
+          sub->c = c;
+          sub->topic = mg_strdup(topic);
+          sub->qos = qos;
+          LIST_ADD_HEAD(struct sub, &s_subs, sub);
+          MG_INFO(
+              ("SUB %p [%.*s]", c->fd, (int) sub->topic.len, sub->topic.buf));
+          // Change '+' to '*' for topic matching using mg_match
+          for (size_t i = 0; i < sub->topic.len; i++) {
+            if (sub->topic.buf[i] == '+') ((char *) sub->topic.buf)[i] = '*';
+          }
+          resp[num_topics++] = qos;
+        }
+        mg_mqtt_send_header(c, MQTT_CMD_SUBACK, 0, num_topics + 2);
+        uint16_t id = mg_htons(mm->id);
+        mg_send(c, &id, 2);
+        mg_send(c, resp, num_topics);
+        break;
+      }
+      case MQTT_CMD_PUBLISH: {
+        // Client published message. Push to all subscribed channels
+        MG_INFO(("PUB %p [%.*s] -> [%.*s]", c->fd, (int) mm->data.len,
+                 mm->data.buf, (int) mm->topic.len, mm->topic.buf));
+        for (struct sub *sub = s_subs; sub != NULL; sub = sub->next) {
+          if (mg_match(mm->topic, sub->topic, NULL)) {
+            struct mg_mqtt_opts pub_opts;
+            memset(&pub_opts, 0, sizeof(pub_opts));
+            pub_opts.topic = mm->topic;
+            pub_opts.message = mm->data;
+            pub_opts.qos = 1, pub_opts.retain = false;
+            mg_mqtt_pub(sub->c, &pub_opts);
+          }
+        }
+        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;
+  } else if (ev == MG_EV_CLOSE) {
+    // Client disconnects. Remove from the subscription list
+    for (struct sub *next, *sub = s_subs; sub != NULL; sub = next) {
+      next = sub->next;
+      if (c != sub->c) continue;
+      MG_INFO(("UNSUB %p [%.*s]", c->fd, (int) sub->topic.len, sub->topic.buf));
+      LIST_DELETE(struct sub, &s_subs, sub);
+    }
+  }
+}
+
+int main(void) {
+  struct mg_mgr mgr;                // Event manager
+  signal(SIGINT, signal_handler);   // Setup signal handlers - exist event
+  signal(SIGTERM, signal_handler);  // manager loop on SIGINT and SIGTERM
+  mg_mgr_init(&mgr);                // Initialise event manager
+  MG_INFO(("Starting on %s", s_listen_on));      // Inform that we're starting
+  mg_mqtt_listen(&mgr, s_listen_on, fn, NULL);   // Create MQTT listener
+  while (s_signo == 0) mg_mgr_poll(&mgr, 1000);  // Event loop, 1s timeout
+  mg_mgr_free(&mgr);                             // Cleanup
+  return 0;
+}

tutorials/mqtt/mqtt-server/mongoose.c

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+../../../mongoose.c

tutorials/mqtt/mqtt-server/mongoose.h

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+../../../mongoose.h