Fix EF migrations in ASP.NET 2

Per this post: dotnet/aspnetcore#2213

Author: bradymholt

api/Models/DesignTimeDefaultDbContext.cs

@@ -0,0 +1,23 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Design;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.Extensions.Configuration;
+
+namespace aspnetCoreReactTemplate.Models
+{
+    public class BloggingContextFactory : IDesignTimeDbContextFactory<DefaultDbContext>
+    {
+        public DefaultDbContext CreateDbContext(string[] args)
+        {
+            var config = new ConfigurationBuilder()
+                  .SetBasePath(System.IO.Directory.GetCurrentDirectory())
+                  .AddJsonFile("appsettings.json")
+                  .Build();
+
+            var options = new DbContextOptionsBuilder<DefaultDbContext>();
+            options.UseNpgsql(config.GetConnectionString("defaultConnection"));
+
+            return new DefaultDbContext(options.Options);
+        }
+    }
+}

api/Program.cs

@@ -2,6 +2,7 @@
 using Microsoft.AspNetCore;
 using Microsoft.AspNetCore.Hosting;
 using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
 
 namespace aspnetCoreReactTemplate
 {
@@ -14,10 +15,24 @@ public static void Main(string[] args)
                   .AddJsonFile("appsettings.json")
                   .Build();
 
-            BuildWebHost(config["serverBindingUrl"], args).Run();
+            var host = BuildHost(config["serverBindingUrl"], args);
+            using (var scope = host.Services.CreateScope())
+            {
+                var dbInitializer = scope.ServiceProvider.GetRequiredService<Models.IDefaultDbContextInitializer>();
+                var env = scope.ServiceProvider.GetRequiredService<IHostingEnvironment>();
+                // Apply any pending migrations
+                dbInitializer.Migrate();
+                if (env.IsDevelopment())
+                {
+                    // Seed the database in development mode
+                    dbInitializer.Seed().GetAwaiter().GetResult();
+                }
+            }
+
+            host.Run();
         }
 
-        public static IWebHost BuildWebHost(string serverBindingUrl, string[] args) =>
+        public static IWebHost BuildHost(string serverBindingUrl, string[] args) =>
             WebHost.CreateDefaultBuilder(args)
             .UseContentRoot(Directory.GetCurrentDirectory())
             .UseUrls(serverBindingUrl)

api/Startup.cs

@@ -50,7 +50,7 @@ public void ConfigureServices(IServiceCollection services)
                 options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
                 options.DefaultChallengeScheme = JwtBearerDefaults.AuthenticationScheme;
             })
-            
+
             .AddJwtBearer(config =>
             {
                 config.RequireHttpsMetadata = false;
@@ -76,27 +76,21 @@ public void ConfigureServices(IServiceCollection services)
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
-        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IDefaultDbContextInitializer databaseInitializer)
+        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
         {
             // Log to console (stdout) - in production stdout will be written to /var/log/{{app_name}}.out.log
             loggerFactory.AddConsole(Configuration.GetSection("logging"));
             loggerFactory.AddDebug();
 
-            // Apply any pending migrations
-            // Do not call EnsureCreated() b/c it does not log to _EFMigrationsHistory table (Ref: https://github.com/aspnet/EntityFramework/issues/3875)
-            databaseInitializer.Migrate();
-
             if (env.IsDevelopment())
             {
-                databaseInitializer.Seed().GetAwaiter().GetResult();
-
                 // Configure Webpack Middleware (Ref: http://blog.stevensanderson.com/2016/05/02/angular2-react-knockout-apps-on-aspnet-core/)
                 //  - Intercepts requests for webpack bundles and routes them through Webpack - this prevents needing to run Webpack file watcher separately
                 //  - Enables Hot module replacement (HMR)
                 app.UseWebpackDevMiddleware(new WebpackDevMiddlewareOptions
                 {
                     HotModuleReplacement = true,
-                    HotModuleReplacementClientOptions = new Dictionary<string, string> {{ "reload", "true" }}, 
+                    HotModuleReplacementClientOptions = new Dictionary<string, string> {{ "reload", "true" }},
                     ReactHotModuleReplacement = true,
                     ConfigFile = System.IO.Path.Combine(Configuration["webClientPath"], "webpack.config.js")
                 });