feat[auth, client-id]: support username/password authentication; support

custom mqtt client ids

Author: fridayy

examples/mqtt_client_example/src/mqtt_client_example.erl

@@ -27,7 +27,10 @@ start() ->
     %% Start the MQTT client.
     %%
     Config = #{
-        url => "mqtt://mqtt.eclipseprojects.io",
+        url => "mqtt://broker.hivemq.com",
+        % username => "some-user", % optional
+        % password => "some-password", % optional)
+        % client_id => "atomvm-client", % optional (generated if missing)
         connected_handler => fun handle_connected/1
     },
     {ok, _MQTT} = mqtt_client:start(Config),

markdown/mqtt_client.md

@@ -63,7 +63,7 @@ The input parameter to the `start/1` function is an Erlang `map` structure, cont
 
     %% erlang
     Config = #{
-        url => "mqtt://mqtt.eclipseprojects.io",
+        url => "mqtt://broker.hivemq.com",
         connected_handler => fun handle_connected/1,
         disconnected_handler => fun handle_disconnected/1,
         error_handler => handle_error/2

ports/atomvm_mqtt_client.c

@@ -61,6 +61,7 @@ static const char *const unsubscribe_failed_atom =        ATOM_STR("\x12", "unsu
 static const char *const unsubscribed_atom =            ATOM_STR("\xC", "unsubscribed");
 static const char *const url_atom =                     ATOM_STR("\x3", "url");
 static const char *const username_atom =                ATOM_STR("\x8", "username");
+static const char *const client_id_atom =                ATOM_STR("\x9", "client_id");
 
 // error codes
 static const char *const bad_username_atom =            ATOM_STR("\x0C", "bad_username");
@@ -700,12 +701,11 @@ void atomvm_mqtt_client_init(GlobalContext *global)
     esp_log_level_set("MQTT_CLIENT", ESP_LOG_VERBOSE);
 }
 
-// NB. Caller assumes ownership of returned string
-static char *maybe_get_string(term kv, AtomString key, GlobalContext *global)
+static char* maybe_get_string_or_default(term kv, AtomString key, char* default_value, GlobalContext *global)
 {
     term value_term = interop_kv_get_value(kv, key, global);
     if (!term_is_string(value_term) && !term_is_binary(value_term)) {
-        return NULL;
+        return default_value;
     }
 
     int ok;
@@ -717,6 +717,12 @@ static char *maybe_get_string(term kv, AtomString key, GlobalContext *global)
     return value_str;
 }
 
+// NB. Caller assumes ownership of returned string
+static char *maybe_get_string(term kv, AtomString key, GlobalContext *global)
+{
+   return maybe_get_string_or_default(kv, key, NULL, global);
+}
+
 // NB. Caller assumes ownership of returned string
 // static char *get_string_default(term kv, AtomString key, AtomString default_value, GlobalContext *global)
 // {
@@ -785,16 +791,23 @@ Context *atomvm_mqtt_client_create_port(GlobalContext *global, term opts)
     UNUSED(port);
     char *username_str = maybe_get_string(opts, username_atom, global);
     char *password_str = maybe_get_string(opts, password_atom, global);
-    // char *cert_str = maybe_get_string(opts, cert_atom, global);
+    char *client_id = maybe_get_string_or_default(opts, client_id_atom, get_default_client_id(), global);
 
     // Note that char * values passed into this struct are copied into the MQTT state
-    const char *client_id = get_default_client_id();
     esp_mqtt_client_config_t mqtt_cfg = {
 #if ESP_IDF_VERSION_MAJOR >= 5
         .broker.address.uri = url_str,
-        .credentials.client_id = client_id
+        .credentials = {
+            .username = username_str,
+            .client_id = client_id,
+            .authentication = {
+                .password = password_str
+            }
+        },
 #else
         .uri = url_str,
+        .username = username_str,
+        .password = password_str
         .client_id = client_id,
         .user_context = (void *) ctx
 #endif
@@ -805,6 +818,7 @@ Context *atomvm_mqtt_client_create_port(GlobalContext *global, term opts)
     free(host_str);
     free(username_str);
     free(password_str);
+    free(client_id);
 
     if (UNLIKELY(IS_NULL_PTR(client))) {
         ESP_LOGE(TAG, "Error: Unable to initialize MQTT client.\n");

src/mqtt_client.erl

@@ -92,8 +92,7 @@
     error_handler => fun((mqtt(), error()) -> any()),
     username => binary_or_string(),
     password => binary_or_string(),
-    client_id => binary_or_string(),
-    trusted_cert => binary_or_string()
+    client_id => binary_or_string()
 }.
 
 -type error_type() :: esp_tls | connection_refused | undefined.
@@ -494,7 +493,11 @@ init(Config) ->
     try
         Self = self(),
         Port = erlang:open_port({spawn, "atomvm_mqtt_client"}, [
-            {receiver, Self}, {url, maps:get(url, Config)}
+            {receiver, Self}, 
+            {url, maps:get(url, Config)},
+            {username, maps:get(username, Config)},
+            {password, maps:get(password, Config)},
+            {client_id, maps:get(client_id, Config)}
         ]),
         {ok, #state{
             port = Port,