fix GetAsync's return IGetOperation with correct Cas value

Author: shenke

Enyim.Caching.Tests/MemcachedClientCasTests.cs

@@ -1,14 +1,13 @@
 using Enyim.Caching.Memcached;
+using Newtonsoft.Json.Linq;
 using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Text;
+using System.Threading.Tasks;
 using Xunit;
 
 namespace Enyim.Caching.Tests
 {
 
-	public class MemcachedClientCasTests : MemcachedClientTestsBase
+    public class MemcachedClientCasTests : MemcachedClientTestsBase
 	{
 
 		[Fact]
@@ -35,7 +34,72 @@ public void When_Storing_Item_With_Invalid_Cas_Result_Is_Not_Successful()
 			StoreAssertFail(casResult);
 		}
 
-	}
+
+        [Fact]
+        public async Task When_Storing_Item_With_Valid_Cas_Result_Is_Successful_Async()
+        {
+            var key = GetUniqueKey("cas");
+            var value = GetRandomString();
+            var comment = new Comment
+            {
+                Author = key,
+                Text = value
+            };
+
+            var storeResult = Store(StoreMode.Add, key, comment);
+            StoreAssertPass(storeResult);
+
+            var casResult1 = await _client.GetAsync(key);
+            GetAssertPass(casResult1, comment);
+
+            var casResult2 = await _client.GetAsync<Comment>(key);
+            GetAssertPass(casResult2, comment);
+        }
+
+        /// <summary>
+        /// comment
+        /// because <see cref="IMemcachedClient"/> use <see cref="Newtonsoft"/> as default serialization tool,
+        /// so <see cref="IMemcachedClient.GetAsync(string)"/> will return <see cref="IGetOperation"/> with <see cref="JObject"/> as <see cref="IGetOperation.Result"/>'s type.
+        /// </summary>
+        public class Comment : IEquatable<Comment>, IEquatable<JObject>
+        {
+            public string Author { get; set; }
+
+            public string Text { get; set; }
+
+            public bool Equals(Comment other)
+            {
+                return other != null && other.Author == Author && other.Text == Text;
+            }
+
+            public bool Equals(JObject other)
+            {
+                return Equals(other?.ToObject<Comment>());
+            }
+
+            public override bool Equals(object obj)
+            {
+                if (obj == null)
+                {
+                    return false;
+                }
+                if (obj is Comment comment)
+                {
+                    return Equals(comment);
+                }
+                if (obj is JObject jObject)
+                {
+                    return Equals(jObject);
+                }
+                return false;
+            }
+
+            public override int GetHashCode()
+            {
+                return HashCode.Combine(Author, Text);
+            }
+        }
+    }
 }
 
 #region [ License information          ]

Enyim.Caching.Tests/MemcachedClientMutateTests.cs

@@ -36,12 +36,16 @@ public async Task When_Touch_Item_Result_Is_Successful()
         {
             var key = GetUniqueKey("touch");
             await _client.AddAsync(key, "value", 1);
-            Assert.True((await _client.GetAsync<string>(key)).Success);
+            var operationResult = await _client.GetAsync<string>(key);
+            Assert.True(operationResult.Success);
+            Assert.NotEqual(0UL, operationResult.Cas);
             var result = await _client.TouchAsync(key, TimeSpan.FromSeconds(60));
             await Task.Delay(1010);
             Assert.True(result.Success, "Success was false");
             Assert.True((result.StatusCode ?? 0) == 0, "StatusCode was not null or 0");
-            Assert.True((await _client.GetAsync<string>(key)).Success);
+            operationResult = await _client.GetAsync<string>(key);
+            Assert.True(operationResult.Success);
+            Assert.NotEqual(0UL, operationResult.Cas);
         }
     }
 }

Enyim.Caching.Tests/MemcachedClientTestsBase.cs

@@ -105,6 +105,14 @@ protected void GetAssertPass(IGetOperationResult result, object expectedValue)
             Assert.Equal(expectedValue, result.Value);
         }
 
+        protected void GetAssertPass<T>(IGetOperationResult<T> result, T expectedValue)
+        {
+            Assert.True(result.Success, "Success was false");
+            Assert.True(result.Cas > 0, "Cas value was 0");
+            Assert.True((result.StatusCode ?? 0) == 0, "StatusCode was neither 0 nor null");
+            Assert.Equal(expectedValue, result.Value);
+        }
+
         protected void GetAssertFail(IGetOperationResult result)
         {
             Assert.False(result.Success, "Success was true");

Enyim.Caching/IMemcachedClient.cs

@@ -17,6 +17,7 @@ public interface IMemcachedClient : IDisposable
         bool Replace(string key, object value, int cacheSeconds);
         Task<bool> ReplaceAsync(string key, object value, int cacheSeconds);
 
+        Task<IGetOperationResult> GetAsync(string key);
         Task<IGetOperationResult<T>> GetAsync<T>(string key);
         Task<T> GetValueAsync<T>(string key);
         Task<T> GetValueOrCreateAsync<T>(string key, int cacheSeconds, Func<Task<T>> generator);

Enyim.Caching/MemcachedClient.cs

@@ -160,6 +160,25 @@ public IGetOperationResult<T> PerformGet<T>(string key)
             }
         }
 
+        private bool CreateGetCommand(string key, out IGetOperationResult result, out IMemcachedNode node, out IGetOperation command)
+        {
+            result = new DefaultGetOperationResultFactory().Create();
+            var hashedKey = this.keyTransformer.Transform(key);
+
+            node = this.pool.Locate(hashedKey);
+            if (node == null)
+            {
+                var errorMessage = $"Unable to locate node with \"{key}\" key";
+                _logger.LogError(errorMessage);
+                result.Fail(errorMessage);
+                command = null;
+                return false;
+            }
+
+            command = this.pool.OperationFactory.Get(hashedKey);
+            return true;
+        }
+
         private bool CreateGetCommand<T>(string key, out IGetOperationResult<T> result, out IMemcachedNode node, out IGetOperation command)
         {
             result = new DefaultGetOperationResultFactory<T>().Create();
@@ -179,11 +198,28 @@ private bool CreateGetCommand<T>(string key, out IGetOperationResult<T> result,
             return true;
         }
 
+        private IGetOperationResult BuildGetCommandResult(IGetOperationResult result, IGetOperation command, IOperationResult commandResult)
+        {
+            if (commandResult.Success)
+            {
+                result.Value = transcoder.Deserialize(command.Result);
+                result.Cas = command.CasValue;
+                result.Pass();
+            }
+            else
+            {
+                commandResult.Combine(result);
+            }
+
+            return result;
+        }
+
         private IGetOperationResult<T> BuildGetCommandResult<T>(IGetOperationResult<T> result, IGetOperation command, IOperationResult commandResult)
         {
             if (commandResult.Success)
             {
                 result.Value = transcoder.Deserialize<T>(command.Result);
+                result.Cas = command.CasValue;
                 result.Pass();
             }
             else
@@ -194,6 +230,27 @@ private IGetOperationResult<T> BuildGetCommandResult<T>(IGetOperationResult<T> r
             return result;
         }
 
+        public async Task<IGetOperationResult> GetAsync(string key)
+        {
+            if (!CreateGetCommand(key, out var result, out var node, out var command))
+            {
+                _logger.LogInformation($"Failed to CreateGetCommand for '{key}' key");
+                return result;
+            }
+
+            try
+            {
+                var commandResult = await node.ExecuteAsync(command);
+                return BuildGetCommandResult(result, command, commandResult);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(0, ex, $"{nameof(GetAsync)}(\"{key}\")");
+                result.Fail(ex.Message, ex);
+                return result;
+            }
+        }
+
         public async Task<IGetOperationResult<T>> GetAsync<T>(string key)
         {
             if (!CreateGetCommand<T>(key, out var result, out var node, out var command))

Enyim.Caching/MemcachedClientT.cs

@@ -120,6 +120,11 @@ public IDictionary<string, T1> Get<T1>(IEnumerable<string> keys)
             return _memcachedClient.Get<T1>(keys);
         }
 
+        public Task<IGetOperationResult> GetAsync(string key)
+        {
+            return _memcachedClient.GetAsync(key);
+        }
+
         public Task<IGetOperationResult<T1>> GetAsync<T1>(string key)
         {
             return _memcachedClient.GetAsync<T1>(key);

Enyim.Caching/NullMemcachedClient.cs

@@ -1,8 +1,6 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
 using System.Net;
-using System.Text;
 using System.Threading.Tasks;
 using Enyim.Caching.Memcached;
 using Enyim.Caching.Memcached.Results;
@@ -104,6 +102,13 @@ public T Get<T>(string key)
             return default(T);
         }
 
+        public Task<IGetOperationResult> GetAsync(string key)
+        {
+            var result = new DefaultGetOperationResultFactory().Create();
+            result.Success = false;
+            return Task.FromResult(result);
+        }
+
         public async Task<IGetOperationResult<T>> GetAsync<T>(string key)
         {
             var result = new DefaultGetOperationResultFactory<T>().Create();