Add support for IDisposable

Directory.Build.props

@@ -24,6 +24,7 @@
     <AnalysisMode>Recommended</AnalysisMode>
     <GraphQLVersion>8.0.0</GraphQLVersion>
     <GraphQLAspNetCore3Version>6.0.0</GraphQLAspNetCore3Version>
+    <NuGetAuditMode>direct</NuGetAuditMode>
   </PropertyGroup>
 
   <ItemGroup>

src/GraphQL.DI/DIObjectGraphBase.cs

@@ -9,6 +9,12 @@ namespace GraphQL.DI;
 /// <summary>
 /// This is a required base type of all DI-created graph types. <see cref="DIObjectGraphBase"/> may be
 /// used if the <see cref="IResolveFieldContext.Source"/> type is <see cref="object"/>.
+/// <para>
+/// If the derived class implements <see cref="IDisposable"/>, the class must be registered within the DI container.
+/// </para>
+/// <para>
+/// When registered within the DI container, the service lifetime must be <see cref="Microsoft.Extensions.DependencyInjection.ServiceLifetime.Transient">Transient</see>.
+/// </para>
 /// </summary>
 public abstract class DIObjectGraphBase<TSource> : IDIObjectGraphBase<TSource>, IResolveFieldContext<TSource>
 {

src/GraphQL.DI/DIObjectGraphType.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics;
 using System.Linq.Expressions;
 using System.Reflection;
 using GraphQL.Types;
@@ -60,13 +61,36 @@ protected override IEnumerable<MemberInfo> GetRegisteredMembers()
     // each field resolver will build a new instance of DIObject
     /// <inheritdoc/>
     protected override LambdaExpression BuildMemberInstanceExpression(MemberInfo memberInfo)
-        => (Expression<Func<IResolveFieldContext, TDIGraph>>)((IResolveFieldContext context) => MemberInstanceFunc(context));
+    {
+        // use an explicit type here rather than simply LambdaExpression
+        Expression<Func<IResolveFieldContext, TDIGraph>> func;
+        if (typeof(IDisposable).IsAssignableFrom(typeof(TDIGraph))) {
+            func = (IResolveFieldContext context) => MemberInstanceDisposableFunc(context);
+        } else {
+            func = (IResolveFieldContext context) => MemberInstanceFunc(context);
+        }
+        return func;
+    }
 
     /// <inheritdoc/>
     private static TDIGraph MemberInstanceFunc(IResolveFieldContext context)
     {
         // create a new instance of DIObject, filling in any constructor arguments from DI
-        var graph = ActivatorUtilities.GetServiceOrCreateInstance<TDIGraph>(context.RequestServices ?? throw new MissingRequestServicesException());
+        var graph = ActivatorUtilities.GetServiceOrCreateInstance<TDIGraph>(context.RequestServices ?? ThrowMissingRequestServicesException());
+        // set the context
+        graph.Context = context;
+        // return the object
+        return graph;
+
+        static IServiceProvider ThrowMissingRequestServicesException() => throw new MissingRequestServicesException();
+    }
+
+    /// <inheritdoc/>
+    private static TDIGraph MemberInstanceDisposableFunc(IResolveFieldContext context)
+    {
+        // pull DIObject from dependency injection, as it is disposable and must be managed by DI
+        var graph = (context.RequestServices ?? throw new MissingRequestServicesException()).GetService<TDIGraph>()
+            ?? throw new InvalidOperationException($"Could not resolve an instance of {typeof(TDIGraph).Name} from the service provider. DI graph types that implement IDisposable must be registered in the service provider.");
         // set the context
         graph.Context = context;
         // return the object

src/GraphQL.DI/GraphQLBuilderExtensions.cs

@@ -18,6 +18,26 @@ public static IGraphQLBuilder AddDIGraphTypes(this IGraphQLBuilder builder)
         return builder;
     }
 
+    /// <summary>
+    /// Scans the calling assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/>
+    /// and registers them as transients within the DI container.
+    /// </summary>
+    public static IGraphQLBuilder AddDIGraphBases(this IGraphQLBuilder builder)
+        => AddDIGraphBases(builder, Assembly.GetCallingAssembly());
+
+    /// <summary>
+    /// Scans the specified assembly for classes that implement <see cref="IDIObjectGraphBase"/>
+    /// and registers them as transients within the DI container.
+    /// </summary>
+    public static IGraphQLBuilder AddDIGraphBases(this IGraphQLBuilder builder, Assembly assembly)
+    {
+        foreach (var type in assembly.GetTypes()
+            .Where(x => x.IsClass && !x.IsAbstract && typeof(IDIObjectGraphBase).IsAssignableFrom(x))) {
+            builder.Services.TryRegister(type, type, ServiceLifetime.Transient);
+        }
+        return builder;
+    }
+
     /// <summary>
     /// Scans the calling assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/> and
     /// registers clr type mappings on the schema between that <see cref="DIObjectGraphType{TDIGraph, TSource}"/>

src/GraphQL.DI/GraphQLDIBuilderExtensions.cs

@@ -0,0 +1,63 @@
+using System.Reflection;
+using GraphQL.DI;
+
+namespace GraphQL;
+
+/// <summary>
+/// Provides extension methods to configure GraphQL.NET services within a dependency injection framework.
+/// </summary>
+public static class GraphQLDIBuilderExtensions
+{
+    /// <summary>
+    /// Performs the following:
+    /// <list type="bullet">
+    /// <item>
+    /// Registers <see cref="DIObjectGraphType{TDIGraph}"/> and
+    /// <see cref="DIObjectGraphType{TDIGraph, TSource}"/> as generic types.
+    /// </item>
+    /// <item>
+    /// Scans the calling assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/>
+    /// and registers them as transients within the DI container.
+    /// </item>
+    /// <item>
+    /// Scans the calling assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/> and
+    /// registers clr type mappings on the schema between that <see cref="DIObjectGraphType{TDIGraph, TSource}"/>
+    /// (constructed from that class and its source type), and the source type.
+    /// Skips classes where the source type is <see cref="object"/>, or where the class is marked with
+    /// the <see cref="DoNotMapClrTypeAttribute"/>, or where another graph type would be automatically mapped
+    /// to the specified type, or where a graph type has already been registered to the specified clr type.
+    /// </item>
+    /// </list>
+    /// </summary>
+    public static IGraphQLBuilder AddDI(this IGraphQLBuilder builder)
+        => AddDI(builder, Assembly.GetCallingAssembly());
+
+    /// <summary>
+    /// Performs the following:
+    /// <list type="bullet">
+    /// <item>
+    /// Registers <see cref="DIObjectGraphType{TDIGraph}"/> and
+    /// <see cref="DIObjectGraphType{TDIGraph, TSource}"/> as generic types.
+    /// </item>
+    /// <item>
+    /// Scans the specified assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/>
+    /// and registers them as transients within the DI container.
+    /// </item>
+    /// <item>
+    /// Scans the specified assembly for classes that implement <see cref="IDIObjectGraphBase{TSource}"/> and
+    /// registers clr type mappings on the schema between that <see cref="DIObjectGraphType{TDIGraph, TSource}"/>
+    /// (constructed from that class and its source type), and the source type.
+    /// Skips classes where the source type is <see cref="object"/>, or where the class is marked with
+    /// the <see cref="DoNotMapClrTypeAttribute"/>, or where another graph type would be automatically mapped
+    /// to the specified type, or where a graph type has already been registered to the specified clr type.
+    /// </item>
+    /// </list>
+    /// </summary>
+    public static IGraphQLBuilder AddDI(this IGraphQLBuilder builder, Assembly assembly)
+    {
+        return builder
+            .AddDIGraphTypes()
+            .AddDIGraphBases(assembly)
+            .AddDIClrTypeMappings(assembly);
+    }
+}