Improves setting expirations on multiple cache keys

Ensures that setting expirations for multiple cache keys
correctly publishes invalidation messages and handles empty
expiration dictionaries efficiently. This prevents unnecessary
message bus calls when no expirations are set, and guarantees
invalidation messages are sent with the correct keys after
setting the expirations on the distributed cache.

Author: niemyjski

src/Foundatio/Caching/HybridAwareCacheClient.cs

@@ -199,13 +199,16 @@ public async Task SetExpirationAsync(string key, TimeSpan expiresIn)
         await _messagePublisher.PublishAsync(new HybridCacheClient.InvalidateCache { CacheId = _cacheId, Keys = [key] }).AnyContext();
     }
 
-    public Task SetAllExpirationAsync(IDictionary<string, TimeSpan?> expirations)
+    public async Task SetAllExpirationAsync(IDictionary<string, TimeSpan?> expirations)
     {
         if (expirations is null)
             throw new ArgumentNullException(nameof(expirations));
 
-        return _distributedCache.SetAllExpirationAsync(expirations);
-        // TODO: await _messagePublisher.PublishAsync(new HybridCacheClient.InvalidateCache { CacheId = _cacheId, Keys = [key] }).AnyContext();
+        if (expirations.Count is 0)
+            return;
+
+        await _distributedCache.SetAllExpirationAsync(expirations).AnyContext();
+        await _messagePublisher.PublishAsync(new HybridCacheClient.InvalidateCache { CacheId = _cacheId, Keys = expirations.Keys.ToArray() }).AnyContext();
     }
 
     public async Task<double> SetIfHigherAsync(string key, double value, TimeSpan? expiresIn = null)

src/Foundatio/Caching/HybridCacheClient.cs

@@ -420,13 +420,12 @@ public async Task SetAllExpirationAsync(IDictionary<string, TimeSpan?> expiratio
         if (expirations is null)
             throw new ArgumentNullException(nameof(expirations));
 
+        if (expirations.Count is 0)
+            return;
+
         await _localCache.SetAllExpirationAsync(expirations).AnyContext();
         await _distributedCache.SetAllExpirationAsync(expirations).AnyContext();
-
-        if (expirations.Count > 0)
-        {
-            await _messageBus.PublishAsync(new InvalidateCache { CacheId = _cacheId, Keys = expirations.Keys.ToArray() }).AnyContext();
-        }
+        await _messageBus.PublishAsync(new InvalidateCache { CacheId = _cacheId, Keys = expirations.Keys.ToArray() }).AnyContext();
     }
 
     public async Task<double> SetIfHigherAsync(string key, double value, TimeSpan? expiresIn = null)

src/Foundatio/Caching/InMemoryCacheClient.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Reflection;
 using System.Text.RegularExpressions;
@@ -953,8 +954,12 @@ public Task<bool> ExistsAsync(string key)
         if (keys is null)
             throw new ArgumentNullException(nameof(keys));
 
-        var result = new Dictionary<string, TimeSpan?>();
-        foreach (string key in keys)
+        string[] keysArray = keys.ToArray();
+        if (keysArray.Length is 0)
+            return Task.FromResult<IDictionary<string, TimeSpan?>>(ReadOnlyDictionary<string, TimeSpan?>.Empty);
+
+        var result = new Dictionary<string, TimeSpan?>(keysArray.Length);
+        foreach (string key in keysArray)
         {
             if (String.IsNullOrEmpty(key))
                 throw new ArgumentNullException(nameof(key), "Key cannot be null or empty");