Add musician example for derived types deserialization

Controllers/MusiciansController.cs

@@ -0,0 +1,9 @@
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Mvc;
+
+[ApiController]
+[Route("musicians")]
+public class MusiciansController : ControllerBase
+{
+    public ActionResult Post(IEnumerable<Musician> musiciansToCreate) => Accepted(musiciansToCreate);
+}

DerivedTypesSerializationExample.csproj

@@ -1,7 +1,10 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
-
   <PropertyGroup>
     <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
-
-</Project>
+  <ItemGroup>
+    <PackageReference Include="Newtonsoft.Json" Version="12.0.3"/>
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.4"/>
+    <PackageReference Include="JsonSubTypes" Version="1.7.0"/>
+  </ItemGroup>
+</Project>

Models/Musician.cs

@@ -0,0 +1,27 @@
+using JsonSubTypes;
+using Newtonsoft.Json;
+
+// one possible solution is to use JsonSubTypes attributes
+// [JsonConverter(typeof(JsonSubtypes), nameof(Musician.InstrumentType))]
+// [JsonSubtypes.KnownSubType(typeof(Guitarist), "Guitar")]
+// [JsonSubtypes.KnownSubType(typeof(Pianist), "Piano")]
+public abstract class Musician
+{
+    public abstract string InstrumentType { get; }
+    public string FirstName { get; set; }
+    public string LastName { get; set; }
+
+    public class Guitarist : Musician
+    {
+        public override string InstrumentType { get; } = "Guitar";
+        public int StringCount { get; set; }
+        public bool CanPlayWonderwall { get; set; }
+    }
+
+    public class Pianist : Musician
+    {
+        public override string InstrumentType { get; } = "Piano";
+        public int HandSpanRating { get; set; }
+    }
+}
+

MusicianCustomConverterExample.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
+
+// You could write a custom JsonConverter to tell the serializer how to act.
+public class MusicianConverter : JsonConverter<Musician>
+{
+    public override Musician ReadJson(JsonReader reader, Type objectType, [AllowNull] Musician existingValue, bool hasExistingValue, JsonSerializer serializer)
+    {
+        var jObject = JObject.Load(reader);
+        var typeDiscriminator = jObject["instrumentType"].Value<string>();
+        switch (typeDiscriminator)
+        {
+            case "Guitar":
+                return serializer.Deserialize<Musician.Guitarist>(reader);              
+            case "Piano":
+                return serializer.Deserialize<Musician.Pianist>(reader);    
+            default:
+                throw new NotSupportedException();
+        }   
+    }
+
+    public override void WriteJson(JsonWriter writer, [AllowNull] Musician value, JsonSerializer serializer)
+    {
+        throw new NotImplementedException();
+    }
+}

Program.cs

@@ -1,12 +1,5 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Hosting;
-using Microsoft.Extensions.Logging;
-
 namespace DerivedTypesSerializationExample
 {
     public class Program
@@ -20,7 +13,7 @@ public static IHostBuilder CreateHostBuilder(string[] args) =>
             Host.CreateDefaultBuilder(args)
                 .ConfigureWebHostDefaults(webBuilder =>
                 {
-                    webBuilder.UseStartup<Startup>();
+                    webBuilder.UseStartup<Startup>();    
                 });
     }
 }

Startup.cs

@@ -1,12 +1,9 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
+using JsonSubTypes;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Hosting;
-using Microsoft.AspNetCore.Http;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
+using Newtonsoft.Json;
 
 namespace DerivedTypesSerializationExample
 {
@@ -16,6 +13,19 @@ public class Startup
         // For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
         public void ConfigureServices(IServiceCollection services)
         {
+            services
+                .AddControllers()
+                .AddNewtonsoftJson(options =>
+                {
+                    options.SerializerSettings.Converters.Add(
+                        JsonSubtypesConverterBuilder
+                        .Of(typeof(Musician), nameof(Musician.InstrumentType))
+                        .RegisterSubtype(typeof(Musician.Guitarist), "Guitar")
+                        .RegisterSubtype(typeof(Musician.Pianist), "Piano")
+                        .SerializeDiscriminatorProperty()
+                        .Build()
+                    );
+                });
         }
 
         // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
@@ -27,14 +37,7 @@ public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
             }
 
             app.UseRouting();
-
-            app.UseEndpoints(endpoints =>
-            {
-                endpoints.MapGet("/", async context =>
-                {
-                    await context.Response.WriteAsync("Hello World!");
-                });
-            });
+            app.UseEndpoints(e => e.MapControllers());
         }
     }
 }

example-http-requests/post-musicians.http

@@ -0,0 +1,18 @@
+POST http://localhost:5000/musicians HTTP/1.1
+Content-Type: application/json
+
+[
+  {
+    "instrumentType": "Guitar",
+    "stringCount": 6,
+    "canPlayWonderwall": true,
+    "firstName": "Noel",
+    "lastName": "Gallagher"
+  },
+  {
+    "instrumentType": "Piano",
+    "handSpanRating": 15,
+    "firstName": "Claude",
+    "lastName": "Debussy"
+  }
+]