From 87ab420599d4910a5ecab86a3752f68ddb72e26d Mon Sep 17 00:00:00 2001
From: Daniel Wigton <daniel@stonecottageweb.com>
Date: Tue, 2 Jul 2024 07:11:37 -0500
Subject: deduplicate events in queryRelays

---
 src/nostr_service.cpp       | 17 +++++++++++------
 test/nostr_service_test.cpp |  4 ++--
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/nostr_service.cpp b/src/nostr_service.cpp
index 5adca3b..10d9fc6 100644
--- a/src/nostr_service.cpp
+++ b/src/nostr_service.cpp
@@ -1,5 +1,6 @@
 #include "nostr.hpp"
 #include "client/web_socket_client.hpp"
+#include <unordered_set>
 
 using namespace nlohmann;
 using namespace std;
@@ -213,8 +214,10 @@ vector<shared_ptr<Event>> NostrService::queryRelays(shared_ptr<Filters> filters)
 
     vector<future<tuple<string, bool>>> requestFutures;
 
+    unordered_set<string> uniqueEventIds;
+
     // Send the same query to each relay.  As events trickle in from each relay, they will be added
-    // to the events vector.  Multiple copies of an event may be received if the same event is
+    // to the events vector.  Duplicate copies of the same event will be ignored, as events are
     // stored on multiple relays.  The function will block until all of the relays send an EOSE or
     // CLOSE message.
     for (const string relay : this->_activeRelays)
@@ -225,13 +228,17 @@ vector<shared_ptr<Event>> NostrService::queryRelays(shared_ptr<Filters> filters)
         auto [uri, success] = this->_client->send(
             request,
             relay,
-            [this, &relay, &events, &eosePromise](string payload)
+            [this, &relay, &events, &eosePromise, &uniqueEventIds](string payload)
             {
                 this->onSubscriptionMessage(
                     payload,
-                    [&events](const string&, shared_ptr<Event> event)
+                    [&events, &uniqueEventIds](const string&, shared_ptr<Event> event)
                     {
-                        events.push_back(event);
+                        // Check if the event is unique before adding.
+                        if (uniqueEventIds.insert(event->id).second)
+                        {
+                            events.push_back(event);
+                        }
                     },
                     [relay, &eosePromise](const string&)
                     {
@@ -272,8 +279,6 @@ vector<shared_ptr<Event>> NostrService::queryRelays(shared_ptr<Filters> filters)
     }
     this->closeSubscription(subscriptionId);
 
-    // TODO: De-duplicate events in the vector before returning.
-
     return events;
 };
 
diff --git a/test/nostr_service_test.cpp b/test/nostr_service_test.cpp
index 5867e8e..4e29960 100644
--- a/test/nostr_service_test.cpp
+++ b/test/nostr_service_test.cpp
@@ -773,8 +773,8 @@ TEST_F(NostrServiceTest, QueryRelays_ReturnsEvents_UpToEOSE)
     auto filters = make_shared<nostr::Filters>(getKind0And1TestFilters());
     auto results = nostrService->queryRelays(filters);
 
-    // TODO: Check results size when the queryRelays method deduplicates results before returning.
-    // ASSERT_EQ(results.size(), testEvents.size());
+    // Check results size to ensure there are no duplicates.
+    ASSERT_EQ(results.size(), testEvents.size());
 
     // Check that the results contain the expected events.
     for (auto resultEvent : results)
-- 
cgit