Open relay subscriptions for a filter request

2 files changed, 67 insertions, 3 deletions

diff --git a/include/nostr.hpp b/include/nostr.hpp
index 8041efe..22d9956 100644
--- a/include/nostr.hpp
+++ b/include/nostr.hpp
@@ -142,12 +142,22 @@ public:
     */
     std::tuple<RelayList, RelayList> publishEvent(Event event);
 
-    // TODO: Add methods for reading events from relays.
+    /**
+     * @brief Queries all open relay connections for events matching the given set of filters.
+     * @returns A tuple of `RelayList` objects, of the form `<successes, failures>`, indicating
+     * to which relays the request was successfully sent, and which relays did not successfully
+     * receive the request.
+     */
+    std::tuple<RelayList, RelayList> queryRelays(Filters filters);
+
+    // TODO: Write a method that receives events for an active subscription.
+    // TODO: Write a method that closes active subscriptions.
 
 private:
     std::mutex _propertyMutex;
     RelayList _defaultRelays;
     RelayList _activeRelays;
+    std::unordered_map<std::string, std::vector<std::string>> _subscriptionIds;
     client::IWebSocketClient* _client;
 
     /**
@@ -182,5 +192,11 @@ private:
      * @brief Closes the connection from the client to the given relay.
      */
     void disconnect(std::string relay);
+
+    /**
+     * @brief Generates a unique subscription ID that may be used to identify event requests.
+     * @returns A stringified UUID.
+     */
+    std::string generateSubscriptionId();
 };
 } // namespace nostr
diff --git a/src/nostr_service.cpp b/src/nostr_service.cpp
index 4f4aadc..3025b96 100644
--- a/src/nostr_service.cpp
+++ b/src/nostr_service.cpp
@@ -1,3 +1,6 @@
+#include <boost/uuid/uuid.hpp>
+#include <boost/uuid/uuid_generators.hpp>
+#include <boost/uuid/uuid_io.hpp>
 #include <plog/Init.h>
 #include <plog/Log.h>
 #include <websocketpp/client.hpp>
@@ -7,6 +10,9 @@
 #include "client/web_socket_client.hpp"
 
 using std::async;
+using boost::uuids::random_generator;
+using boost::uuids::to_string;
+using boost::uuids::uuid;
 using std::future;
 using std::lock_guard;
 using std::make_tuple;
@@ -104,8 +110,6 @@ void NostrService::closeRelayConnections(RelayList relays)
 
 tuple<RelayList, RelayList> NostrService::publishEvent(Event event)
 {
-    // TODO: Add validation function.
-
     RelayList successfulRelays;
     RelayList failedRelays;
 
@@ -141,6 +145,44 @@ tuple<RelayList, RelayList> NostrService::publishEvent(Event event)
     return make_tuple(successfulRelays, failedRelays);
 };
 
+tuple<RelayList, RelayList> NostrService::queryRelays(Filters filters)
+{
+    RelayList successfulRelays;
+    RelayList failedRelays;
+
+    vector<future<tuple<string, bool>>> requestFutures;
+    for (const string relay : this->_activeRelays)
+    {
+        string subscriptionId = this->generateSubscriptionId();
+        this->_subscriptionIds[relay].push_back(subscriptionId);
+        string request = filters.serialize(subscriptionId);
+
+        future<tuple<string, bool>> requestFuture = async([this, &relay, &request]() {
+            return this->_client->send(request, relay);
+        });
+        requestFutures.push_back(move(requestFuture));
+    }
+
+    for (auto& publishFuture : requestFutures)
+    {
+        auto [relay, isSuccess] = publishFuture.get();
+        if (isSuccess)
+        {
+            successfulRelays.push_back(relay);
+        }
+        else
+        {
+            failedRelays.push_back(relay);
+        }
+    }
+
+    size_t targetCount = this->_activeRelays.size();
+    size_t successfulCount = successfulRelays.size();
+    PLOG_INFO << "Published event to " << successfulCount << "/" << targetCount << " target relays.";
+
+    return make_tuple(successfulRelays, failedRelays);
+};
+
 RelayList NostrService::getConnectedRelays(RelayList relays)
 {
     PLOG_VERBOSE << "Identifying connected relays.";
@@ -245,4 +287,10 @@ void NostrService::disconnect(string relay)
     lock_guard<mutex> lock(this->_propertyMutex);
     this->eraseActiveRelay(relay);
 };
+
+string NostrService::generateSubscriptionId()
+{
+    uuid uuid = random_generator()();
+    return to_string(uuid);
+};
 } // namespace nostr