aspnetcore/src/Microsoft.AspNet.Http.Exten.../UseMiddlewareExtensions.cs

59 lines
2.7 KiB
C#

// Copyright (c) Microsoft Open Technologies, Inc. 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.Framework.DependencyInjection;
using System.Threading.Tasks;
using Microsoft.AspNet.Http;
namespace Microsoft.AspNet.Builder
{
public static class UseMiddlewareExtensions
{
public static IApplicationBuilder UseMiddleware<T>(this IApplicationBuilder builder, params object[] args)
{
return builder.UseMiddleware(typeof(T), args);
}
public static IApplicationBuilder UseMiddleware(this IApplicationBuilder builder, Type middleware, params object[] args)
{
var applicationServices = builder.ApplicationServices;
return builder.Use(next =>
{
var instance = ActivatorUtilities.CreateInstance(builder.ApplicationServices, middleware, new[] { next }.Concat(args).ToArray());
var methodinfo = middleware.GetMethod("Invoke", BindingFlags.Instance | BindingFlags.Public);
var parameters = methodinfo.GetParameters();
if (parameters[0].ParameterType != typeof(HttpContext))
{
throw new Exception("TODO: Middleware Invoke method must take first argument of HttpContext");
}
if (parameters.Length == 1)
{
return (RequestDelegate)methodinfo.CreateDelegate(typeof(RequestDelegate), instance);
}
return context =>
{
var serviceProvider = context.RequestServices ?? context.ApplicationServices ?? applicationServices;
if (serviceProvider == null)
{
throw new Exception("TODO: IServiceProvider is not available");
}
var arguments = new object[parameters.Length];
arguments[0] = context;
for(var index = 1; index != parameters.Length; ++index)
{
var serviceType = parameters[index].ParameterType;
arguments[index] = serviceProvider.GetService(serviceType);
if (arguments[index] == null)
{
throw new Exception(string.Format("TODO: No service for type '{0}' has been registered.", serviceType));
}
}
return (Task)methodinfo.Invoke(instance, arguments);
};
});
}
}
}