Merge branch 'feat/get_transport' into 'master'

feat: Allow users to get the transport in use

See merge request espressif/esp-mqtt!216

Author: euripedesrocha

include/mqtt_client.h

@@ -29,6 +29,11 @@ typedef void *esp_event_handler_t;
 
 typedef struct esp_mqtt_client *esp_mqtt_client_handle_t;
 
+#define MQTT_OVER_TCP_SCHEME "mqtt"
+#define MQTT_OVER_SSL_SCHEME "mqtts"
+#define MQTT_OVER_WS_SCHEME  "ws"
+#define MQTT_OVER_WSS_SCHEME "wss"
+
 /**
  * @brief *MQTT* event types.
  *
@@ -661,6 +666,27 @@ int esp_mqtt_client_get_outbox_size(esp_mqtt_client_handle_t client);
  */
 esp_err_t esp_mqtt_dispatch_custom_event(esp_mqtt_client_handle_t client, esp_mqtt_event_t *event);
 
+/**
+ * @brief Get a transport from the scheme
+ *
+ * Allows extra settings to be made on the selected transport,
+ * for convenience the scheme used by the mqtt client are defined as
+ * MQTT_OVER_TCP_SCHEME, MQTT_OVER_SSL_SCHEME, MQTT_OVER_WS_SCHEME and MQTT_OVER_WSS_SCHEME
+ * If the transport_scheme is NULL and the client was set with a custom transport the custom transport will be returned.
+ *
+ * Notes:
+ * - This function should be called only on MQTT_EVENT_BEFORE_CONNECT.
+ * - The intetion is to provide a way to set different configurations than the ones available from client config.
+ * - If esp_mqtt_client_destroy is called the returned pointer will be invalidated.
+ * - All the required settings should be made in the MQTT_EVENT_BEFORE_CONNECT event handler
+ *
+ * @param client            *MQTT* client handle
+ * @param transport_scheme  Transport handle to search for.
+ * @return the transport handle
+ *         NULL in case of error
+ *
+*/
+esp_transport_handle_t esp_mqtt_client_get_transport(esp_mqtt_client_handle_t client, char *transport_scheme);
 #ifdef __cplusplus
 }
 #endif //__cplusplus

mqtt_client.c

@@ -24,11 +24,6 @@ static const char *TAG = "mqtt_client";
 ESP_EVENT_DEFINE_BASE(MQTT_EVENTS);
 #endif
 
-#define MQTT_OVER_TCP_SCHEME "mqtt"
-#define MQTT_OVER_SSL_SCHEME "mqtts"
-#define MQTT_OVER_WS_SCHEME  "ws"
-#define MQTT_OVER_WSS_SCHEME "wss"
-
 const static int STOPPED_BIT = (1 << 0);
 const static int RECONNECT_BIT = (1 << 1);
 const static int DISCONNECT_BIT = (1 << 2);
@@ -1587,9 +1582,6 @@ static void esp_mqtt_task(void *pv)
             break;
         case MQTT_STATE_INIT:
             xEventGroupClearBits(client->status_bits, RECONNECT_BIT | DISCONNECT_BIT);
-            client->event.event_id = MQTT_EVENT_BEFORE_CONNECT;
-            esp_mqtt_dispatch_event_with_msgid(client);
-
 
             client->transport = client->config->transport;
             if (!client->transport) {
@@ -1617,6 +1609,9 @@ static void esp_mqtt_task(void *pv)
             esp_mqtt_set_ssl_transport_properties(client->transport_list, client->config);
 #endif
 
+            client->event.event_id = MQTT_EVENT_BEFORE_CONNECT;
+            esp_mqtt_dispatch_event_with_msgid(client);
+
             if (esp_transport_connect(client->transport,
                                       client->config->host,
                                       client->config->port,
@@ -2282,3 +2277,13 @@ int esp_mqtt_client_get_outbox_size(esp_mqtt_client_handle_t client)
 
     return outbox_size;
 }
+
+esp_transport_handle_t esp_mqtt_client_get_transport(esp_mqtt_client_handle_t client, char *transport_scheme){
+    if (client == NULL || (transport_scheme == NULL && client->config->transport == NULL)) {
+        return NULL;
+    }
+    if (transport_scheme == NULL && client->config->transport != NULL) {
+        return client->config->transport;
+    }
+    return esp_transport_list_get_transport(client->transport_list, transport_scheme);
+}