From 0e72b2fcc6f1b4b69d397adab6485988967806cd Mon Sep 17 00:00:00 2001
From: "Owen.Morgan-Jones" <owen.morganjones@hymans.co.uk>
Date: Sat, 21 Mar 2026 11:56:01 +0000
Subject: [PATCH] Adds caching to feature flag repository

---
 .../CachingFeatureFlagRepository.cs           | 23 +++++++++++++++++++
 .../Repositories/CachingMemberRepository.cs   | 16 +++++++------
 .../ServiceCollectionExtensions.cs            |  5 +++-
 3 files changed, 36 insertions(+), 8 deletions(-)
 create mode 100644 Bottomly/Repositories/CachingFeatureFlagRepository.cs

diff --git a/Bottomly/Repositories/CachingFeatureFlagRepository.cs b/Bottomly/Repositories/CachingFeatureFlagRepository.cs
new file mode 100644
index 0000000..beee094
--- /dev/null
+++ b/Bottomly/Repositories/CachingFeatureFlagRepository.cs
@@ -0,0 +1,23 @@
+using Microsoft.Extensions.Caching.Memory;
+
+namespace Bottomly.Repositories;
+
+public class CachingFeatureFlagRepository(IFeatureFlagRepository inner, IMemoryCache cache) : IFeatureFlagRepository
+{
+    private const string KeyPrefix = "feature_flag:";
+
+    public Task<bool> GetAsync(string flagId) =>
+        cache.GetOrCreateAsync(KeyPrefix + flagId, _ => inner.GetAsync(flagId));
+
+    public async Task SetAsync(string flagId, bool enabled)
+    {
+        await inner.SetAsync(flagId, enabled);
+        cache.Set(KeyPrefix + flagId, enabled);
+    }
+
+    public async Task SeedAsync(string flagId, bool defaultValue)
+    {
+        await inner.SeedAsync(flagId, defaultValue);
+        cache.Remove(KeyPrefix + flagId);
+    }
+}
\ No newline at end of file
diff --git a/Bottomly/Repositories/CachingMemberRepository.cs b/Bottomly/Repositories/CachingMemberRepository.cs
index 628cc1c..235e6c0 100644
--- a/Bottomly/Repositories/CachingMemberRepository.cs
+++ b/Bottomly/Repositories/CachingMemberRepository.cs
@@ -69,14 +69,16 @@ public async Task<List<Member>> GetBySlackIdsAsync(IEnumerable<string> slackIds)
             }
         }
 
-        if (misses.Count > 0)
+        if (misses.Count <= 0)
         {
-            var fetched = await inner.GetBySlackIdsAsync(misses);
-            foreach (var member in fetched)
-            {
-                CacheMember(member);
-                result.Add(member);
-            }
+            return result;
+        }
+
+        var fetched = await inner.GetBySlackIdsAsync(misses);
+        foreach (var member in fetched)
+        {
+            CacheMember(member);
+            result.Add(member);
         }
 
         return result;
diff --git a/Bottomly/Repositories/ServiceCollectionExtensions.cs b/Bottomly/Repositories/ServiceCollectionExtensions.cs
index a50d41b..ec40f77 100644
--- a/Bottomly/Repositories/ServiceCollectionExtensions.cs
+++ b/Bottomly/Repositories/ServiceCollectionExtensions.cs
@@ -14,7 +14,10 @@ public static IServiceCollection AddBottomlyRepositories(this IServiceCollection
             new CachingMemberRepository(
                 new MemberRepository(sp.GetRequiredService<IMongoDatabase>()),
                 sp.GetRequiredService<IMemoryCache>()));
-        services.AddSingleton<IFeatureFlagRepository, FeatureFlagRepository>();
+        services.AddSingleton<IFeatureFlagRepository>(sp =>
+            new CachingFeatureFlagRepository(
+                new FeatureFlagRepository(sp.GetRequiredService<IMongoDatabase>()),
+                sp.GetRequiredService<IMemoryCache>()));
 
         return services;
     }