Bug #409267 - add multiple server list to the connectOptions

src/MQTTAsync.h

@@ -13,6 +13,7 @@
  * Contributors:
  *    Ian Craggs - initial API and implementation 
  *    Ian Craggs, Allan Stockdill-Mander - SSL connections
+ *    Ian Craggs - multiple server connection support
  *******************************************************************************/
 
 /********************************************************************/
@@ -541,7 +542,10 @@ typedef struct
 {
 	/** The eyecatcher for this structure.  must be MQTC. */
 	char struct_id[4];
-	/** The version number of this structure.  Must be 0 or 1.  0 signifies no SSL options */
+	/** The version number of this structure.  Must be 0, 1 or 2.  
+	  * 0 signifies no SSL options and no serverURIs
+	  * 1 signifies no serverURIs 
+	  */
 	int struct_version;
 	/** The "keep alive" interval, measured in seconds, defines the maximum time
       * that should pass without communication between the client and the server
@@ -629,10 +633,23 @@ typedef struct
       * provide access to the context information in the callback.
       */
 	void* context;
+	/**
+	  * The number of entries in the serverURIs array.
+	  */
+	int serverURIcount;
+	/**
+	  * An array of null-terminated strings specifying the servers to
+      * which the client will connect. Each string takes the form <i>protocol://host:port</i>.
+      * <i>protocol</i> must be <i>tcp</i> or <i>ssl</i>. For <i>host</i>, you can 
+      * specify either an IP address or a domain name. For instance, to connect to
+      * a server running on the local machines with the default MQTT port, specify
+      * <i>tcp://localhost:1883</i>.
+      */    
+	char** serverURIs;
 } MQTTAsync_connectOptions;
 
 
-#define MQTTAsync_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 1, 60, 1, 10, NULL, NULL, NULL, 30, 20, NULL, NULL }
+#define MQTTAsync_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 2, 60, 1, 10, NULL, NULL, NULL, 30, 20, NULL, NULL, 0, NULL}
 
 /**
   * This function attempts to connect a previously-created client (see

src/MQTTClient.c

@@ -15,6 +15,7 @@
  *    Ian Craggs - bug 384016 - segv setting will message
  *    Ian Craggs - bug 384053 - v1.0.0.7 - stop MQTTClient_receive on socket error 
  *    Ian Craggs, Allan Stockdill-Mander - add ability to connect with SSL
+ *    Ian Craggs - multiple server connection support
  *******************************************************************************/
 
 #include <stdlib.h>
@@ -704,55 +705,14 @@ void Protocol_processPublication(Publish* publish, Clients* client)
 }
 
 
-int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions* options)
+int MQTTClient_connectURI(MQTTClient handle, MQTTClient_connectOptions* options, char* serverURI)
 {
 	MQTTClients* m = handle;
-	int rc = SOCKET_ERROR;
 	START_TIME_TYPE start;
 	long millisecsTimeout = 30000L;
+	int rc = SOCKET_ERROR;
 
 	FUNC_ENTRY;
-	Thread_lock_mutex(mqttclient_mutex);
-
-	if (options == NULL)
-	{
-		rc = MQTTCLIENT_NULL_PARAMETER;
-		goto exit;
-	}
-
-	if (strncmp(options->struct_id, "MQTC", 4) != 0 || (options->struct_version != 0 && options->struct_version != 1))
-	{
-		rc = MQTTCLIENT_BAD_STRUCTURE;
-		goto exit;
-	}
-
-	if (options->will) /* check validity of will options structure */
-	{
-		if (strncmp(options->will->struct_id, "MQTW", 4) != 0 || options->will->struct_version != 0)
-		{
-			rc = MQTTCLIENT_BAD_STRUCTURE;
-			goto exit;
-		}
-	}
-	
-#if defined(OPENSSL)
-	if (options->struct_version != 0 && options->ssl) /* check validity of SSL options structure */
-	{
-		if (strncmp(options->ssl->struct_id, "MQTS", 4) != 0 || options->ssl->struct_version != 0)
-		{
-			rc = MQTTCLIENT_BAD_STRUCTURE;
-			goto exit;
-		}
-	}
-#endif
-
-	if ((options->username && !UTF8_validateString(options->username)) ||
-		(options->password && !UTF8_validateString(options->password)))
-	{
-		rc = MQTTCLIENT_BAD_UTF8_STRING;
-		goto exit;
-	}
-
 	millisecsTimeout = options->connectTimeout * 1000;
 	start = MQTTClient_start_clock();
 	if (m->ma && !running)
@@ -788,11 +748,11 @@ int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions* options)
 	m->c->password = options->password;
 	m->c->retryInterval = options->retryInterval;
 
-	Log(TRACE_MIN, -1, "Connecting to serverURI %s", m->serverURI);
+	Log(TRACE_MIN, -1, "Connecting to serverURI %s", serverURI);
 #if defined(OPENSSL)
-	rc = MQTTProtocol_connect(m->serverURI, m->c, m->ssl);
+	rc = MQTTProtocol_connect(serverURI, m->c, m->ssl);
 #else
-	rc = MQTTProtocol_connect(m->serverURI, m->c);
+	rc = MQTTProtocol_connect(serverURI, m->c);
 #endif
 	if (rc == SOCKET_ERROR)
 		goto exit;
@@ -919,7 +879,84 @@ exit:
 		MQTTClient_disconnect(handle, 0); /* not "internal" because we don't want to call connection lost */
 		Thread_lock_mutex(mqttclient_mutex);
 	}
+	FUNC_EXIT_RC(rc);
+	return rc;
+}
+
+
+int MQTTClient_connect(MQTTClient handle, MQTTClient_connectOptions* options)
+{
+	MQTTClients* m = handle;
+	int rc = SOCKET_ERROR;
+
+	FUNC_ENTRY;
+	Thread_lock_mutex(mqttclient_mutex);
+
+	if (options == NULL)
+	{
+		rc = MQTTCLIENT_NULL_PARAMETER;
+		goto exit;
+	}
+
+	if (strncmp(options->struct_id, "MQTC", 4) != 0 || 
+		(options->struct_version != 0 && options->struct_version != 1 && options->struct_version != 2))
+	{
+		rc = MQTTCLIENT_BAD_STRUCTURE;
+		goto exit;
+	}
+
+	if (options->will) /* check validity of will options structure */
+	{
+		if (strncmp(options->will->struct_id, "MQTW", 4) != 0 || options->will->struct_version != 0)
+		{
+			rc = MQTTCLIENT_BAD_STRUCTURE;
+			goto exit;
+		}
+	}
+	
+#if defined(OPENSSL)
+	if (options->struct_version != 0 && options->ssl) /* check validity of SSL options structure */
+	{
+		if (strncmp(options->ssl->struct_id, "MQTS", 4) != 0 || options->ssl->struct_version != 0)
+		{
+			rc = MQTTCLIENT_BAD_STRUCTURE;
+			goto exit;
+		}
+	}
+#endif
+
+	if ((options->username && !UTF8_validateString(options->username)) ||
+		(options->password && !UTF8_validateString(options->password)))
+	{
+		rc = MQTTCLIENT_BAD_UTF8_STRING;
+		goto exit;
+	}
+
+	if (options->struct_version < 2 || options->serverURIcount == 0)
+		rc = MQTTClient_connectURI(handle, options, m->serverURI);
+	else
+	{
+		int i;
+		
+		for (i = 0; i < options->serverURIcount; ++i)
+		{
+			char* serverURI = options->serverURIs[i];
 			
+			if (strncmp(URI_TCP, serverURI, strlen(URI_TCP)) == 0)
+				serverURI += strlen(URI_TCP);
+#if defined(OPENSSL)
+			else if (strncmp(URI_SSL, serverURI, strlen(URI_SSL)) == 0)
+			{
+				serverURI += strlen(URI_SSL);
+				m->ssl = 1;
+			}
+#endif
+			if ((rc = MQTTClient_connectURI(handle, options, serverURI)) == MQTTCLIENT_SUCCESS)
+				break;
+		}	
+	}
+
+exit:
     if (m->c->will)
     {
 		free(m->c->will);

src/MQTTClient.h

@@ -13,6 +13,7 @@
  * Contributors:
  *    Ian Craggs - initial API and implementation and/or initial documentation
  *    Ian Craggs, Allan Stockdill-Mander - SSL updates
+ *    Ian Craggs - multiple server connection support
  *******************************************************************************/
 
 /**
@@ -544,9 +545,22 @@ typedef struct
     * application does not make use of SSL, set this pointer to NULL.
     */
 	MQTTClient_SSLOptions* ssl;
+	/**
+	  * The number of entries in the serverURIs array.
+	  */
+	int serverURIcount;
+	/**
+	  * An array of null-terminated strings specifying the servers to
+      * which the client will connect. Each string takes the form <i>protocol://host:port</i>.
+      * <i>protocol</i> must be <i>tcp</i> or <i>ssl</i>. For <i>host</i>, you can 
+      * specify either an IP address or a domain name. For instance, to connect to
+      * a server running on the local machines with the default MQTT port, specify
+      * <i>tcp://localhost:1883</i>.
+      */    
+	char** serverURIs;
 } MQTTClient_connectOptions;
 
-#define MQTTClient_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 1, 60, 1, 1, NULL, NULL, NULL, 30, 20, NULL }
+#define MQTTClient_connectOptions_initializer { {'M', 'Q', 'T', 'C'}, 2, 60, 1, 1, NULL, NULL, NULL, 30, 20, NULL, 0, NULL }
 
 /**
   * MQTTClient_libraryInfo is used to store details relating to the currently used