Bugfix: Implement last will correctly, fix some QoS handling and allow for clean session

Re #4

src/mqtt.c

@@ -214,13 +214,13 @@ MQTTStatus mqtt_reconnect(MQTTHandle *handle, MQTTEventHandler callback, void *c
     return MQTT_STATUS_OK;
 }
 
-MQTTStatus mqtt_subscribe(MQTTHandle *handle, char *topic, MQTTPublishEventHandler callback) {
+MQTTStatus mqtt_subscribe(MQTTHandle *handle, char *topic, MQTTQosLevel qos_level, MQTTPublishEventHandler callback) {
     if (!handle->reader_alive) {
         handle->error_handler(handle, MQTT_Error_Connection_Reset);
         return MQTT_STATUS_ERROR;
     }
-    add_subscription(handle, topic, callback);
-    return (send_subscribe_packet(handle, topic) ? MQTT_STATUS_OK : MQTT_STATUS_ERROR);
+    add_subscription(handle, topic, qos_level, callback);
+    return (send_subscribe_packet(handle, topic, qos_level) ? MQTT_STATUS_OK : MQTT_STATUS_ERROR);
 }
 
 MQTTStatus mqtt_unsubscribe(MQTTHandle *handle, char *topic) {

src/mqtt.h

@@ -11,9 +11,14 @@ typedef struct {
     uint16_t port;   /**< Port the broker listens on, set to 0 for 1883 default */
 
     char *client_id; /**< Client identification */
+    bool clean_session; /**< Set to true to reset the session on reconnect */
 
     char *username;  /**< User name, set to NULL to connect anonymously */
     char *password;  /**< Password, set to NULL to connect without password */
+
+    char *last_will_topic;   /**< last will topic that is automatically published on connection loss */
+    char *last_will_message; /**< last will message */
+    bool last_will_retain;   /**< tell server to retain last will message */
 } MQTTConfig;
 
 typedef enum {
@@ -84,10 +89,11 @@ MQTTStatus mqtt_reconnect(MQTTHandle *handle, MQTTEventHandler callback, void *c
  *
  * @param handle: MQTT Handle from `mqtt_connect`
  * @param topic: Topic to subscribe
+ * @param qos_level: Maximum qos level to subscribe to
  * @param callback: Callback function to call when receiving something for that topic
  * @returns: Status code
  */
-MQTTStatus mqtt_subscribe(MQTTHandle *handle, char *topic, MQTTPublishEventHandler callback);
+MQTTStatus mqtt_subscribe(MQTTHandle *handle, char *topic, MQTTQosLevel qos_level, MQTTPublishEventHandler callback);
 
 /**
  * Un-Subscribe from a topic

src/protocol.c

@@ -26,12 +26,12 @@ bool send_connect_packet(MQTTHandle *handle) {
     payload->client_id = handle->config->client_id;
     payload->protocol_level = 4;
     payload->keepalive_interval = 60;
+    payload->clean_session = handle->config->clean_session;
 
-    // TODO: support last will
-    // payload->will_topic = "test/lastwill";
-    // payload->will_message = "disconnected";
-    // payload->will_qos = MQTT_QOS_1;
-    // payload->retain_will = true;
+    payload->will_topic = handle->config->last_will_topic;
+    payload->will_message = handle->config->last_will_message;
+    payload->will_qos = MQTT_QOS_0;
+    payload->retain_will = handle->config->last_will_retain;
 
     payload->username = handle->config->username;
     payload->password = handle->config->password;

src/protocol.h

@@ -4,7 +4,7 @@
 #include "mqtt.h"
 
 bool send_connect_packet(MQTTHandle *handle);
-bool send_subscribe_packet(MQTTHandle *handle, char *topic);
+bool send_subscribe_packet(MQTTHandle *handle, char *topic, MQTTQosLevel qos);
 bool send_unsubscribe_packet(MQTTHandle *handle, char *topic);
 bool send_publish_packet(MQTTHandle *handle, char *topic, char *message, MQTTQosLevel qos);
 bool send_disconnect_packet(MQTTHandle *handle);

src/subscriptions.c

@@ -1,10 +1,11 @@
 #include "mqtt_internal.h"
 #include "subscriptions.h"
 
-void add_subscription(MQTTHandle *handle, char *topic, MQTTPublishEventHandler callback) {
+void add_subscription(MQTTHandle *handle, char *topic, MQTTQosLevel qos, MQTTPublishEventHandler callback) {
     SubscriptionItem *item = calloc(1, sizeof(SubscriptionItem));
 
     item->topic = topic;
+    item->qos = qos;
     item->handler = callback;
     item->pending = true;
 

src/subscriptions.h

@@ -7,6 +7,7 @@ typedef struct _SubscriptionItem {
     struct _SubscriptionItem *next;
 
     char *topic;
+    MQTTQosLevel qos;
     MQTTPublishEventHandler handler;
     bool pending;
 } SubscriptionItem;
@@ -15,7 +16,7 @@ typedef struct {
     SubscriptionItem *items;
 } Subscriptions;
 
-void add_subscription(MQTTHandle *handle, char *topic, MQTTPublishEventHandler callback);
+void add_subscription(MQTTHandle *handle, char *topic, MQTTQosLevel qos, MQTTPublishEventHandler callback);
 void remove_subscription(MQTTHandle *handle, char *topic);
 void subscription_set_pending(MQTTHandle *handle, char *topic, bool pending);
 

tests/connect_subscribe.c

@@ -37,13 +37,13 @@ void mqtt_connected(MQTTHandle *handle, void *context) {
     LOG("Connected!");
 
     LOG("Trying subscribe on testsuite/mqtt/test...");
-    MQTTStatus result = mqtt_subscribe(handle, "testsuite/mqtt/test", callback);
+    MQTTStatus result = mqtt_subscribe(handle, "testsuite/mqtt/test", MQTT_QOS_0, callback);
     if (result != MQTT_STATUS_OK) {
         LOG("Could not subscribe test");
         exit(1);
     }
 
-    result = mqtt_subscribe(handle, "testsuite/mqtt/test2", callback);
+    result = mqtt_subscribe(handle, "testsuite/mqtt/test2", MQTT_QOS_0, callback);
     if (result != MQTT_STATUS_OK) {
         LOG("Could not subscribe test 2");
         exit(1);
@@ -55,7 +55,7 @@ int main(int argc, char **argv) {
 
     config.client_id = "libmqtt_testsuite";
     config.hostname = "localhost";
-    config.port = 1883;
+    config.clean_session = true;
 
     LOG("Trying to connect to %s...", config.hostname);
     MQTTHandle *mqtt = mqtt_connect(&config, mqtt_connected, NULL, err_handler);