Library and client support for topic-alias.

client/client_props.c

@@ -112,6 +112,9 @@ int cfg_parse_property(struct mosq_config *cfg, int argc, char *argv[], int *idx
 			break;
 
 		case CMD_PUBLISH:
+			if(identifier == MQTT_PROP_TOPIC_ALIAS){
+				cfg->have_topic_alias = true;
+			}
 			if(identifier == MQTT_PROP_SUBSCRIPTION_IDENTIFIER){
 				fprintf(stderr, "Error: %s property not supported for %s in --property argument.\n\n", propname, cmdname);
 				return MOSQ_ERR_INVAL;

client/client_shared.h

@@ -98,6 +98,7 @@ struct mosq_config {
 	mosquitto_property *unsubscribe_props;
 	mosquitto_property *disconnect_props;
 	mosquitto_property *will_props;
+	bool have_topic_alias; /* pub */
 };
 
 int client_config_load(struct mosq_config *config, int pub_or_sub, int argc, char *argv[]);

client/pub_client.c

@@ -55,6 +55,18 @@ static char *password = NULL;
 static bool disconnect_sent = false;
 static bool quiet = false;
 static struct mosq_config cfg;
+static bool first_publish = true;
+
+int my_publish(struct mosquitto *mosq, int *mid, const char *topic, int payloadlen, void *payload, int qos, bool retain)
+{
+	if(cfg.protocol_version == MQTT_PROTOCOL_V5 && cfg.have_topic_alias && first_publish == false){
+		return mosquitto_publish_with_properties(mosq, mid, NULL, payloadlen, payload, qos, retain, cfg.publish_props);
+	}else{
+		first_publish = false;
+		return mosquitto_publish_with_properties(mosq, mid, topic, payloadlen, payload, qos, retain, cfg.publish_props);
+	}
+}
+
 
 void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
 {
@@ -65,10 +77,10 @@ void my_connect_callback(struct mosquitto *mosq, void *obj, int result)
 			case MSGMODE_CMD:
 			case MSGMODE_FILE:
 			case MSGMODE_STDIN_FILE:
-				rc = mosquitto_publish_with_properties(mosq, &mid_sent, topic, msglen, message, qos, retain, cfg.publish_props);
+				rc = my_publish(mosq, &mid_sent, topic, msglen, message, qos, retain);
 				break;
 			case MSGMODE_NULL:
-				rc = mosquitto_publish_with_properties(mosq, &mid_sent, topic, 0, NULL, qos, retain, cfg.publish_props);
+				rc = my_publish(mosq, &mid_sent, topic, 0, NULL, qos, retain);
 				break;
 			case MSGMODE_STDIN_LINE:
 				status = STATUS_CONNACK_RECVD;
@@ -416,7 +428,7 @@ int main(int argc, char *argv[])
 					buf_len_actual = strlen(buf);
 					if(buf[buf_len_actual-1] == '\n'){
 						buf[buf_len_actual-1] = '\0';
-						rc2 = mosquitto_publish_with_properties(mosq, &mid_sent, topic, buf_len_actual-1, buf, qos, retain, cfg.publish_props);
+						rc2 = my_publish(mosq, &mid_sent, topic, buf_len_actual-1, buf, qos, retain);
 						if(rc2){
 							if(!quiet) fprintf(stderr, "Error: Publish returned %d, disconnecting.\n", rc2);
 							mosquitto_disconnect_with_properties(mosq, cfg.disconnect_props);

lib/actions.c

@@ -38,14 +38,35 @@ int mosquitto_publish_with_properties(struct mosquitto *mosq, int *mid, const ch
 	struct mosquitto_message_all *message;
 	uint16_t local_mid;
 	int queue_status;
-
-	if(!mosq || !topic || qos<0 || qos>2) return MOSQ_ERR_INVAL;
-	if(STREMPTY(topic)) return MOSQ_ERR_INVAL;
-	if(mosquitto_validate_utf8(topic, strlen(topic))) return MOSQ_ERR_MALFORMED_UTF8;
-	if(payloadlen < 0 || payloadlen > MQTT_MAX_PAYLOAD) return MOSQ_ERR_PAYLOAD_SIZE;
-
-	if(mosquitto_pub_topic_check(topic) != MOSQ_ERR_SUCCESS){
-		return MOSQ_ERR_INVAL;
+	const mosquitto_property *p;
+	bool have_topic_alias;
+
+	if(!mosq || qos<0 || qos>2) return MOSQ_ERR_INVAL;
+	if(!topic || STREMPTY(topic)){
+		if(topic) topic = NULL;
+
+		if(mosq->protocol == mosq_p_mqtt5){
+			p = properties;
+			have_topic_alias = false;
+			while(p){
+				if(p->identifier == MQTT_PROP_TOPIC_ALIAS){
+					have_topic_alias = true;
+					break;
+				}
+				p = p->next;
+			}
+			if(have_topic_alias == false){
+				return MOSQ_ERR_INVAL;
+			}
+		}else{
+			return MOSQ_ERR_INVAL;
+		}
+	}else{
+		if(mosquitto_validate_utf8(topic, strlen(topic))) return MOSQ_ERR_MALFORMED_UTF8;
+		if(payloadlen < 0 || payloadlen > MQTT_MAX_PAYLOAD) return MOSQ_ERR_PAYLOAD_SIZE;
+		if(mosquitto_pub_topic_check(topic) != MOSQ_ERR_SUCCESS){
+			return MOSQ_ERR_INVAL;
+		}
 	}
 
 	local_mid = mosquitto__mid_generate(mosq);
@@ -62,10 +83,12 @@ int mosquitto_publish_with_properties(struct mosquitto *mosq, int *mid, const ch
 		message->next = NULL;
 		message->timestamp = mosquitto_time();
 		message->msg.mid = local_mid;
-		message->msg.topic = mosquitto__strdup(topic);
-		if(!message->msg.topic){
-			message__cleanup(&message);
-			return MOSQ_ERR_NOMEM;
+		if(topic){
+			message->msg.topic = mosquitto__strdup(topic);
+			if(!message->msg.topic){
+				message__cleanup(&message);
+				return MOSQ_ERR_NOMEM;
+			}
 		}
 		if(payloadlen){
 			message->msg.payloadlen = payloadlen;

lib/send_publish.c

@@ -51,7 +51,6 @@ int send__publish(struct mosquitto *mosq, uint16_t mid, const char *topic, uint3
 #endif
 #endif
 	assert(mosq);
-	assert(topic);
 
 #if defined(WITH_BROKER) && defined(WITH_WEBSOCKETS)
 	if(mosq->sock == INVALID_SOCKET && !mosq->wsi) return MOSQ_ERR_NO_CONN;
@@ -137,9 +136,12 @@ int send__real_publish(struct mosquitto *mosq, uint16_t mid, const char *topic,
 	int rc;
 
 	assert(mosq);
-	assert(topic);
 
-	packetlen = 2+strlen(topic) + payloadlen;
+	if(topic){
+		packetlen = 2+strlen(topic) + payloadlen;
+	}else{
+		packetlen = 2 + payloadlen;
+	}
 	if(qos > 0) packetlen += 2; /* For message id */
 	if(mosq->protocol == mosq_p_mqtt5){
 		proplen = property__get_length_all(properties);
@@ -163,7 +165,11 @@ int send__real_publish(struct mosquitto *mosq, uint16_t mid, const char *topic,
 		return rc;
 	}
 	/* Variable header (topic string) */
-	packet__write_string(packet, topic, strlen(topic));
+	if(topic){
+		packet__write_string(packet, topic, strlen(topic));
+	}else{
+		packet__write_uint16(packet, 0);
+	}
 	if(qos > 0){
 		packet__write_uint16(packet, mid);
 	}