Remove UseServer(string) overload

- Removed the overload that takes a string because it's broken

#731

samples/SampleStartups/StartupExternallyControlled.cs

@@ -29,7 +29,7 @@ namespace SampleStartups
         public void Start()
         {
             _host = new WebHostBuilder()
-                .UseServer("Microsoft.AspNetCore.Server.Kestrel")
+                //.UseKestrel()
                 .UseStartup<StartupExternallyControlled>()
                 .Start(_urls.ToArray());
         }

samples/SampleStartups/StartupFullControl.cs

@@ -22,7 +22,7 @@ namespace SampleStartups
 
             var host = new WebHostBuilder()
                 .UseConfiguration(config) // Default set of configurations to use, may be subsequently overridden 
-                .UseServer("Microsoft.AspNetCore.Server.Kestrel") // Set the server manually
+              //.UseKestrel()
                 .UseContentRoot(Directory.GetCurrentDirectory()) // Override the content root with the current directory
                 .UseUrls("http://*:1000", "https://*:902")
                 .UseEnvironment("Development")

samples/SampleStartups/StartupHelloWorld.cs

@@ -21,7 +21,7 @@ namespace SampleStartups
         public static void Main(string[] args)
         {
             var host = new WebHostBuilder()
-                .UseServer("Microsoft.AspNetCore.Server.Kestrel")
+              //.UseKestrel()
                 .UseStartup<StartupHelloWorld>()
                 .Build();
 

src/Microsoft.AspNetCore.Hosting.Abstractions/WebHostDefaults.cs

@@ -10,7 +10,6 @@ namespace Microsoft.AspNetCore.Hosting
         
         public static readonly string DetailedErrorsKey = "detailedErrors";
         public static readonly string EnvironmentKey = "environment";
-        public static readonly string ServerKey = "server";
         public static readonly string WebRootKey = "webroot";
         public static readonly string CaptureStartupErrorsKey = "captureStartupErrors";
         public static readonly string ServerUrlsKey = "server.urls";

src/Microsoft.AspNetCore.Hosting/Internal/WebHostOptions.cs

@@ -24,7 +24,6 @@ namespace Microsoft.AspNetCore.Hosting.Internal
             DetailedErrors = ParseBool(configuration, WebHostDefaults.DetailedErrorsKey);
             CaptureStartupErrors = ParseBool(configuration, WebHostDefaults.CaptureStartupErrorsKey);
             Environment = configuration[WebHostDefaults.EnvironmentKey];
-            ServerAssembly = configuration[WebHostDefaults.ServerKey];
             WebRoot = configuration[WebHostDefaults.WebRootKey];
             ContentRootPath = configuration[WebHostDefaults.ContentRootKey];
         }
@@ -37,8 +36,6 @@ namespace Microsoft.AspNetCore.Hosting.Internal
 
         public string Environment { get; set; }
         
-        public string ServerAssembly { get; set; }
-        
         public string StartupAssembly { get; set; }
 
         public string WebRoot { get; set; }

src/Microsoft.AspNetCore.Hosting/WebHostBuilder.cs

@@ -187,25 +187,6 @@ namespace Microsoft.AspNetCore.Hosting
             // Ensure object pooling is available everywhere.
             services.AddSingleton<ObjectPoolProvider, DefaultObjectPoolProvider>();
 
-            if (!string.IsNullOrEmpty(_options.ServerAssembly))
-            {
-                // Add the server
-                try
-                {
-                    var serverType = ServerLoader.ResolveServerType(_options.ServerAssembly);
-                    services.AddSingleton(typeof(IServer), serverType);
-                }
-                catch (Exception ex)
-                {
-                    var capture = ExceptionDispatchInfo.Capture(ex);
-                    services.AddSingleton<IServer>(_ =>
-                    {
-                        capture.Throw();
-                        return null;
-                    });
-                }
-            }
-
             if (!string.IsNullOrEmpty(_options.StartupAssembly))
             {
                 try

src/Microsoft.AspNetCore.Hosting/WebHostBuilderExtensions.cs

@@ -125,22 +125,6 @@ namespace Microsoft.AspNetCore.Hosting
                     .UseSetting(WebHostDefaults.StartupAssemblyKey, startupAssemblyName);
         }
 
-        /// <summary>
-        /// Specify the assembly containing the server to be used by the web host.
-        /// </summary>
-        /// <param name="hostBuilder">The <see cref="IWebHostBuilder"/> to configure.</param>
-        /// <param name="assemblyName">The name of the assembly containing the server to be used.</param>
-        /// <returns>The <see cref="IWebHostBuilder"/>.</returns>
-        public static IWebHostBuilder UseServer(this IWebHostBuilder hostBuilder, string assemblyName)
-        {
-            if (assemblyName == null)
-            {
-                throw new ArgumentNullException(nameof(assemblyName));
-            }
-
-            return hostBuilder.UseSetting(WebHostDefaults.ServerKey, assemblyName);
-        }
-
         /// <summary>
         /// Specify the server to be used by the web host.
         /// </summary>

test/Microsoft.AspNetCore.Hosting.Tests/WebHostConfigurationsTests.cs

@@ -16,7 +16,6 @@ namespace Microsoft.AspNetCore.Hosting.Tests
             var parameters = new Dictionary<string, string>()
             {
                 { "webroot", "wwwroot"},
-                { "server", "Microsoft.AspNetCore.Server.Kestrel"},
                 { "applicationName", "MyProjectReference"},
                 { "startupAssembly", "MyProjectReference" },
                 { "environment", "Development"},
@@ -27,7 +26,6 @@ namespace Microsoft.AspNetCore.Hosting.Tests
             var config = new WebHostOptions(new ConfigurationBuilder().AddInMemoryCollection(parameters).Build());
 
             Assert.Equal("wwwroot", config.WebRoot);
-            Assert.Equal("Microsoft.AspNetCore.Server.Kestrel", config.ServerAssembly);
             Assert.Equal("MyProjectReference", config.ApplicationName);
             Assert.Equal("MyProjectReference", config.StartupAssembly);
             Assert.Equal("Development", config.Environment);

test/Microsoft.AspNetCore.Hosting.Tests/WebHostTests.cs

@@ -71,13 +71,12 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var vals = new Dictionary<string, string>
             {
-                { "server", "Microsoft.AspNetCore.Hosting.Tests" }
             };
 
             var builder = new ConfigurationBuilder()
                 .AddInMemoryCollection(vals);
             var config = builder.Build();
-            var host = CreateBuilder(config).Build();
+            var host = CreateBuilder(config).UseServer(this).Build();
             host.Start();
             Assert.NotNull(host.Services.GetService<IHostingEnvironment>());
         }
@@ -87,13 +86,12 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var vals = new Dictionary<string, string>
             {
-                { "Server", "Microsoft.AspNetCore.Hosting.Tests" }
             };
 
             var builder = new ConfigurationBuilder()
                 .AddInMemoryCollection(vals);
             var config = builder.Build();
-            var host = CreateBuilder(config).Build();
+            var host = CreateBuilder(config).UseServer(this).Build();
             host.Start();
             Assert.NotNull(host.Services.GetService<IHostingEnvironment>());
         }
@@ -103,13 +101,12 @@ namespace Microsoft.AspNetCore.Hosting
         {
             var vals = new Dictionary<string, string>
             {
-                { "Server", "Microsoft.AspNetCore.Hosting.Tests" }
             };
 
             var builder = new ConfigurationBuilder()
                 .AddInMemoryCollection(vals);
             var config = builder.Build();
-            var host = CreateBuilder(config).Build();
+            var host = CreateBuilder(config).UseServer(this).Build();
             host.Start();
             Assert.NotNull(host.Services.GetService<IHostingEnvironment>());
             Assert.Equal("http://localhost:5000", host.ServerFeatures.Get<IServerAddressesFeature>().Addresses.First());