Add API to fetch all subscribed topics along with a list of clients with their qos for each fo the topics as std::map<std::string, std::list<std::pair<std::string, uint8_t>>

std::map<topic, std::list<std::pair<ClientId, QoS>>

Author: VolkerChristian

src/iot/mqtt/server/broker/Broker.cpp

@@ -183,6 +183,10 @@ namespace iot::mqtt::server::broker {
         return subscribtionTree.getSubscriptions(clientId);
     }
 
+    std::map<std::string, std::list<std::pair<std::string, uint8_t>>> Broker::getSubscriptionTree() const {
+        return subscribtionTree.getSubscriptionTree();
+    }
+
     bool Broker::hasSession(const std::string& clientId) {
         return sessionStore.contains(clientId);
     }

src/iot/mqtt/server/broker/Broker.h

@@ -57,6 +57,9 @@ namespace iot::mqtt::server {
 #include <map>
 #include <memory>
 #include <string>
+#include <utility>
+
+// IWYU pragma: no_include <iterator>
 
 #endif // DOXYGEN_SHOULD_SKIP_THIS
 
@@ -83,6 +86,7 @@ namespace iot::mqtt::server::broker {
         void unsubscribe(const std::string& clientId, const std::string& topic);
 
         std::list<std::string> getSubscriptions(const std::string& clientId) const;
+        std::map<std::string, std::list<std::pair<std::string, uint8_t>>> getSubscriptionTree() const;
 
         bool hasSession(const std::string& clientId);
         bool hasActiveSession(const std::string& clientId);

src/iot/mqtt/server/broker/SubscribtionTree.cpp

@@ -51,7 +51,6 @@
 #include <algorithm>
 #include <nlohmann/json.hpp>
 #include <string>
-#include <utility>
 
 // IWYU pragma: no_include <nlohmann/detail/iterators/iteration_proxy.hpp>
 
@@ -110,6 +109,10 @@ namespace iot::mqtt::server::broker {
         return subscriptions;
     }
 
+    std::map<std::string, std::list<std::pair<std::string, uint8_t>>> SubscribtionTree::getSubscriptionTree() const {
+        return head.getSubscriptionTree();
+    }
+
     void SubscribtionTree::fromJson(const nlohmann::json& json) {
         if (!json.empty()) {
             head.fromJson(json);
@@ -281,6 +284,10 @@ namespace iot::mqtt::server::broker {
         return getSubscriptions("", clientId);
     }
 
+    std::map<std::string, std::list<std::pair<std::string, uint8_t>>> SubscribtionTree::TopicLevel::getSubscriptionTree() const {
+        return getSubscriptionTree("");
+    }
+
     std::list<std::string> SubscribtionTree::TopicLevel::getSubscriptions(const std::string& absoluteTopicLevel,
                                                                           const std::string& clientId) const {
         std::list<std::string> topicLevelList;
@@ -298,6 +305,26 @@ namespace iot::mqtt::server::broker {
         return topicLevelList;
     }
 
+    std::map<std::string, std::list<std::pair<std::string, uint8_t>>>
+    SubscribtionTree::TopicLevel::getSubscriptionTree(const std::string& absoluteTopicLevel) const {
+        std::map<std::string, std::list<std::pair<std::string, uint8_t>>> topicLevelTree;
+
+        for (const auto& [topicLevelName, nextTopicLevel] : topicLevels) {
+            const std::string composedAbsoluteTopicLevelName = absoluteTopicLevel + topicLevelName;
+
+            for (const auto& clientId : nextTopicLevel.clientIds) {
+                topicLevelTree[composedAbsoluteTopicLevelName].emplace_back(clientId);
+            }
+
+            std::map<std::string, std::list<std::pair<std::string, uint8_t>>> subSubscriptionTree =
+                nextTopicLevel.getSubscriptionTree(composedAbsoluteTopicLevelName + "/");
+
+            topicLevelTree.insert(subSubscriptionTree.begin(), subSubscriptionTree.end());
+        }
+
+        return topicLevelTree;
+    }
+
     SubscribtionTree::TopicLevel& SubscribtionTree::TopicLevel::fromJson(const nlohmann::json& json) {
         clientIds.clear();
         topicLevels.clear();

src/iot/mqtt/server/broker/SubscribtionTree.h

@@ -54,6 +54,9 @@ namespace iot::mqtt::server::broker {
 #include <map>
 #include <nlohmann/json_fwd.hpp>
 #include <string>
+#include <utility>
+
+// IWYU pragma: no_include <iterator>
 
 #endif // DOXYGEN_SHOULD_SKIP_THIS
 
@@ -76,6 +79,7 @@ namespace iot::mqtt::server::broker {
         void fromJson(const nlohmann::json& json);
 
         std::list<std::string> getSubscriptions(const std::string& clientId) const;
+        std::map<std::string, std::list<std::pair<std::string, uint8_t>>> getSubscriptionTree() const;
 
         void clear();
 
@@ -95,13 +99,17 @@ namespace iot::mqtt::server::broker {
 
             std::list<std::string> getSubscriptions(const std::string& clientId) const;
 
+            std::map<std::string, std::list<std::pair<std::string, uint8_t>>> getSubscriptionTree() const;
+
             TopicLevel& fromJson(const nlohmann::json& json);
             nlohmann::json toJson() const;
 
             void clear();
 
         private:
             std::list<std::string> getSubscriptions(const std::string& absoluteTopicLevel, const std::string& clientId) const;
+            std::map<std::string, std::list<std::pair<std::string, uint8_t>>>
+            getSubscriptionTree(const std::string& absoluteTopicLevel) const;
 
             iot::mqtt::server::broker::Broker* broker;