aspnetcore/src/Microsoft.AspNetCore.Hosting/Internal/ConfigureServicesBuilder.cs

56 lines
2.0 KiB
C#

// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
using System;
using System.Linq;
using System.Reflection;
using Microsoft.Extensions.DependencyInjection;
namespace Microsoft.AspNetCore.Hosting.Internal
{
public class ConfigureServicesBuilder
{
public ConfigureServicesBuilder(MethodInfo configureServices)
{
MethodInfo = configureServices;
}
public MethodInfo MethodInfo { get; }
public Func<Func<IServiceCollection, IServiceProvider>, Func<IServiceCollection, IServiceProvider>> StartupServiceFilters { get; set; } = f => f;
public Func<IServiceCollection, IServiceProvider> Build(object instance) => services => Invoke(instance, services);
private IServiceProvider Invoke(object instance, IServiceCollection services)
{
return StartupServiceFilters(Startup)(services);
IServiceProvider Startup(IServiceCollection serviceCollection) => InvokeCore(instance, serviceCollection);
}
private IServiceProvider InvokeCore(object instance, IServiceCollection services)
{
if (MethodInfo == null)
{
return null;
}
// Only support IServiceCollection parameters
var parameters = MethodInfo.GetParameters();
if (parameters.Length > 1 ||
parameters.Any(p => p.ParameterType != typeof(IServiceCollection)))
{
throw new InvalidOperationException("The ConfigureServices method must either be parameterless or take only one parameter of type IServiceCollection.");
}
var arguments = new object[MethodInfo.GetParameters().Length];
if (parameters.Length > 0)
{
arguments[0] = services;
}
return MethodInfo.Invoke(instance, arguments) as IServiceProvider;
}
}
}