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 => "some-client", % (optional - defaults to: atomvm-<DEVICE-MAC-ADDRESS>)
         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
@@ -113,7 +113,7 @@ You can publish a message using the `publish/4`
     %% erlang
     Topic = <<"atomvm/topic0">>,
     Message = <<"Hello!">>,
-    MsgId = mqtt_client:publish(MTQQ, Topic, Message).
+    MsgId = mqtt_client:publish(MQTT, Topic, Message).
 
 The above function call will publish a message to the specified topic using the MQTT QoS `at_most_once`.  Note that messages sent with `at_most_once` QoS are not subject to notification.
 
@@ -151,7 +151,7 @@ Subscribe to an MQTT topic by using the `subscribe/3` function.  Specify a topic
         subscribed_handler = fun handle_subscribed/2,
         data_handler = fun handle_data/3
     },
-    ok = mqtt_client:subscribe(MTQQ, Topic, SubscribeOptions).
+    ok = mqtt_client:subscribe(MQTT, Topic, SubscribeOptions).
 
 The `subscribe/3` function will return `{error, already_subscribed}` if the client application is already subscribed to the specified topic.
 
@@ -173,14 +173,14 @@ The `data_handler` will be passed the MQTT client instance, topic on which the m
 
 ### Unsubscribing from an MQTT topic
 
-Use the `unscibscribe/3` function to unsubscribe from a topic.
+Use the `unsubscribe/3` function to unsubscribe from a topic.
 
     %% erlang
     Topic = <<"atomvm/topic0">>,
     UnSubscribeOptions = #{
         unsubscribed_handler = fun handle_unsubscribed/2
     },
-    ok = mqtt_client:unsubscribe(MTQQ, Topic, UnSubscribeOptions).
+    ok = mqtt_client:unsubscribe(MQTT, Topic, UnSubscribeOptions).
 
 The `unsubscribe/3` function will return `{error, not_subscribed}` if the client application is not yet subscribed to the specified topic.
 
@@ -199,6 +199,21 @@ TODO
 
 #### Username/Password authentication
 
+The username and password can be specified either as parameters to `mqtt_client:start/1` in the configuration map or directly in the broker URL (if supported by the broker).
+
+    %% erlang
+    Config = #{
+        url => "mqtts://some-broker.io:8883"
+        username => <<"test">>,
+        password => <<"milkstout">>,
+        ...
+        }
+    % or
+    Config = #{
+        url => "mqtts://test:[email protected]:8883",
+        ...
+        }
+
 #### Connecting via TLS
 
 ##### Client TLS Authentication

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)
 // {
@@ -785,17 +791,26 @@ 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 *client_id_str = maybe_get_string_or_default(opts, client_id_atom, get_default_client_id(), global);
+    // todo: implement cert support
     // char *cert_str = maybe_get_string(opts, cert_atom, 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_str,
+            .authentication = {
+                .password = password_str
+            }
+        },
 #else
         .uri = url_str,
-        .client_id = client_id,
+        .username = username_str,
+        .password = password_str
+        .client_id = client_id_str,
         .user_context = (void *) ctx
 #endif
     };
@@ -805,6 +820,7 @@ Context *atomvm_mqtt_client_create_port(GlobalContext *global, term opts)
     free(host_str);
     free(username_str);
     free(password_str);
+    free(client_id_str);
 
     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,