Improve connecting socket

Enyim.Caching/Configuration/ConfigurationHelper.cs

@@ -73,7 +73,7 @@ public static void CheckForInterface(Type type, Type interfaceType)
             //	throw new System.Configuration.ConfigurationErrorsException("The type " + type.AssemblyQualifiedName + " must implement " + interfaceType.AssemblyQualifiedName);
         }
 
-        public static EndPoint ResolveToEndPoint(string value)
+        public static DnsEndPoint ResolveToEndPoint(string value)
         {
             if (String.IsNullOrEmpty(value))
                 throw new ArgumentNullException("value");
@@ -86,25 +86,8 @@ public static EndPoint ResolveToEndPoint(string value)
             if (!Int32.TryParse(parts[1], out port))
                 throw new ArgumentException("Cannot parse port: " + parts[1], "value");
 
-            return ResolveToEndPoint(parts[0], port);
-        }
-
-        public static EndPoint ResolveToEndPoint(string host, int port)
-        {
-            if (String.IsNullOrEmpty(host))
-                throw new ArgumentNullException("host");
-
-            IPAddress address;
-            // parse as an IP address
-            if (!IPAddress.TryParse(host, out address))
-            {
-                var addresses = Dns.GetHostAddresses(host);
-                address = addresses.FirstOrDefault(ip => ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork);
-                if (address == null)
-                    throw new ArgumentException(String.Format("Could not resolve host '{0}'.", host));
-            }
-            return new IPEndPoint(address, port);
-        }
+            return new DnsEndPoint(parts[0], port);
+        }        
     }
 }
 

Enyim.Caching/Configuration/IMemcachedClientConfiguration.cs

@@ -13,7 +13,7 @@ public interface IMemcachedClientConfiguration
 		/// <summary>
 		/// Gets a list of <see cref="T:IPEndPoint"/> each representing a Memcached server in the pool.
 		/// </summary>
-		IList<EndPoint> Servers { get; }
+		IList<DnsEndPoint> Servers { get; }
 
 		/// <summary>
 		/// Gets the configuration of the socket pool.

Enyim.Caching/Configuration/MemcachedClientConfiguration.cs

@@ -41,21 +41,22 @@ public MemcachedClientConfiguration(
             var options = optionsAccessor.Value;
             if ((options == null || options.Servers.Count == 0) && configuration != null)
             {
-                configuration.GetSection("enyimMemcached").Bind(options);
-            }
-
-            Servers = new List<EndPoint>();
-            foreach (var server in options.Servers)
-            {
-                IPAddress address;
-                if (IPAddress.TryParse(server.Address, out address))
+                var section = configuration.GetSection("enyimMemcached");                
+                if (section.Exists())
                 {
-                    Servers.Add(new IPEndPoint(address, server.Port));
+                    section.Bind(options);                    
                 }
                 else
                 {
-                    Servers.Add(new DnsEndPoint(server.Address, server.Port));
-                }
+                    _logger.LogWarning($"No enyimMemcached setting in appsetting.json. Use default configuration");
+                    options.AddDefaultServer();
+                }                
+            }
+
+            Servers = new List<DnsEndPoint>();
+            foreach (var server in options.Servers)
+            {
+                Servers.Add(new DnsEndPoint(server.Address, server.Port));
             }
 
             SocketPool = new SocketPoolConfiguration();
@@ -187,13 +188,13 @@ public void AddServer(string address)
         /// <param name="port">The port number of the memcached instance.</param>
         public void AddServer(string host, int port)
         {
-            this.Servers.Add(ConfigurationHelper.ResolveToEndPoint(host, port));
+            this.Servers.Add(new DnsEndPoint(host, port));
         }
 
         /// <summary>
         /// Gets a list of <see cref="T:IPEndPoint"/> each representing a Memcached server in the pool.
         /// </summary>
-        public IList<EndPoint> Servers { get; private set; }
+        public IList<DnsEndPoint> Servers { get; private set; }
 
         /// <summary>
         /// Gets the configuration of the socket pool.
@@ -250,7 +251,7 @@ public ITranscoder Transcoder
 
         #region [ interface                     ]
 
-        IList<System.Net.EndPoint> IMemcachedClientConfiguration.Servers
+        IList<System.Net.DnsEndPoint> IMemcachedClientConfiguration.Servers
         {
             get { return this.Servers; }
         }

Enyim.Caching/Configuration/MemcachedClientOptions.cs

@@ -30,6 +30,8 @@ public void AddServer(string address, int port)
             Servers.Add(new Server { Address = address, Port = port });
         }
 
+        public void AddDefaultServer() => AddServer("memcached", 11211);    
+
         public void AddPlainTextAuthenticator(string zone, string userName, string password)
         {
             Authentication = new Authentication

Enyim.Caching/Enyim.Caching.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <Description>EnyimMemcachedCore is a Memcached client library for .NET Core. Usage: Add services.AddEnyimMemcached(...) and app.UseEnyimMemcached() in Startup. Add IMemcachedClient into constructor.</Description>
-    <VersionPrefix>2.1.6</VersionPrefix>
+    <VersionPrefix>2.1.7</VersionPrefix>
     <Authors>cnblogs.com</Authors>
     <TargetFramework>netstandard2.0</TargetFramework>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>

Enyim.Caching/EnyimMemcachedServiceCollectionExtensions.cs

@@ -49,6 +49,11 @@ public static IServiceCollection AddEnyimMemcached(this IServiceCollection servi
                 throw new ArgumentNullException(nameof(configurationSection));
             }
 
+            if(!configurationSection.Exists())
+            {
+                throw new ArgumentNullException($"{configurationSection.Key} in appsettings.json");
+            }
+
             return AddEnyimMemcachedInternal(services, s => s.Configure<MemcachedClientOptions>(configurationSection));
         }
 
@@ -64,7 +69,13 @@ public static IServiceCollection AddEnyimMemcached(this IServiceCollection servi
                 throw new ArgumentNullException(nameof(configuration));
             }
 
-            return AddEnyimMemcachedInternal(services, s => s.Configure<MemcachedClientOptions>(configuration.GetSection(sectionKey)));
+            var section = configuration.GetSection(sectionKey);
+            if (!section.Exists())
+            {
+                throw new ArgumentNullException($"{sectionKey} in appsettings.json");
+            }
+
+            return AddEnyimMemcachedInternal(services, s => s.Configure<MemcachedClientOptions>(section));
         }
 
         private static IServiceCollection AddEnyimMemcachedInternal(IServiceCollection services, Action<IServiceCollection> configure)
@@ -81,6 +92,6 @@ private static IServiceCollection AddEnyimMemcachedInternal(IServiceCollection s
             services.AddSingleton<IDistributedCache>(factory => factory.GetService<MemcachedClient>());
 
             return services;
-        }
+        }        
     }
 }