Added fields to show-case defer and stream

Author: michaelstaib

code/complete/GraphQL/GraphQL.csproj

@@ -12,9 +12,9 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="HotChocolate.AspNetCore" Version="12.0.0" />
-    <PackageReference Include="HotChocolate.Data.EntityFramework" Version="12.0.0" />
-    <PackageReference Include="HotChocolate.PersistedQueries.FileSystem" Version="12.0.0" />
+    <PackageReference Include="HotChocolate.AspNetCore" Version="12.0.1" />
+    <PackageReference Include="HotChocolate.Data.EntityFramework" Version="12.0.1" />
+    <PackageReference Include="HotChocolate.PersistedQueries.FileSystem" Version="12.0.1" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Sqlite" Version="6.0.0-preview.7.21378.4" />
     <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="6.0.0-preview.7.21378.4">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>

code/complete/GraphQL/Speakers/SpeakerNode.cs

@@ -1,11 +1,15 @@
+using System;
 using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
 using System.Threading;
 using System.Threading.Tasks;
 using ConferencePlanner.GraphQL.Data;
 using ConferencePlanner.GraphQL.DataLoader;
 using HotChocolate;
 using HotChocolate.Types;
 using HotChocolate.Types.Relay;
+using Microsoft.EntityFrameworkCore;
 
 namespace ConferencePlanner.GraphQL.Speakers
 {
@@ -26,5 +30,43 @@ public static Task<Speaker> GetSpeakerByIdAsync(
             SpeakerByIdDataLoader speakerById,
             CancellationToken cancellationToken)
             => speakerById.LoadAsync(id, cancellationToken);
+
+        public async Task<IEnumerable<Session>> GetSessionsExpensiveAsync(
+            [Parent] Speaker speaker,
+            SessionBySpeakerIdDataLoader sessionBySpeakerId,
+            CancellationToken cancellationToken)
+        {
+            await Task.Delay(new Random().Next(1000, 3000), cancellationToken);
+
+            return await sessionBySpeakerId.LoadAsync(speaker.Id, cancellationToken);
+        }
+
+        public async IAsyncEnumerable<Session> GetSessionsStreamAsync(
+            [Parent] Speaker speaker,
+            [Service] IDbContextFactory<ApplicationDbContext> contextFactory,
+            [EnumeratorCancellation] CancellationToken cancellationToken)
+        {
+            var random = new Random();
+
+            await Task.Delay(random.Next(500, 1000), cancellationToken);
+            
+            await using var context = contextFactory.CreateDbContext();
+
+            var stream = (IAsyncEnumerable<SessionSpeaker>)context.Speakers
+                .Where(s => s.Id == speaker.Id)
+                .Include(s => s.SessionSpeakers)
+                .SelectMany(s => s.SessionSpeakers)
+                .Include(s => s.Session);
+
+            await foreach (var item in stream.WithCancellation(cancellationToken))
+            {
+                if (item.Session is not null)
+                {
+                    yield return item.Session;
+                }
+
+                await Task.Delay(random.Next(100, 300), cancellationToken);
+            }
+        }
     }
 }