aspnetcore/src/Microsoft.AspNet.Diagnostics/ErrorHandlerMiddleware.cs

80 lines
3.1 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.Threading.Tasks;
using Microsoft.AspNet.Builder;
using Microsoft.AspNet.Http;
using Microsoft.Framework.Logging;
namespace Microsoft.AspNet.Diagnostics
{
public class ErrorHandlerMiddleware
{
private readonly RequestDelegate _next;
private readonly ErrorHandlerOptions _options;
private readonly ILogger _logger;
public ErrorHandlerMiddleware(RequestDelegate next, ILoggerFactory loggerFactory, ErrorHandlerOptions options)
{
_next = next;
_options = options;
_logger = loggerFactory.Create<ErrorHandlerMiddleware>();
if (_options.ErrorHandler == null)
{
_options.ErrorHandler = _next;
}
}
public async Task Invoke(HttpContext context)
{
var responseStarted = false;
try
{
context.Response.OnSendingHeaders(state => responseStarted = true, null);
await _next(context);
}
catch (Exception ex)
{
_logger.WriteError("An unhandled exception has occurred: " + ex.Message, ex);
// We can't do anything if the response has already started, just abort.
if (responseStarted)
{
_logger.WriteWarning("The response has already started, the error handler will not be executed.");
throw;
}
PathString originalPath = context.Request.Path;
if (_options.ErrorHandlingPath.HasValue)
{
context.Request.Path = _options.ErrorHandlingPath;
}
try
{
var errorHandlerFeature = new ErrorHandlerFeature()
{
Error = ex,
};
context.SetFeature<IErrorHandlerFeature>(errorHandlerFeature);
context.Response.StatusCode = 500;
context.Response.Headers.Clear();
// TODO: Try clearing any buffered data. The buffering feature/middleware has not been designed yet.
await _options.ErrorHandler(context);
// TODO: Optional re-throw? We'll re-throw the original exception by default if the error handler throws.
return;
}
catch (Exception ex2)
{
// Suppress secondary exceptions, re-throw the original.
_logger.WriteError("An exception was thrown attempting to execute the error handler.", ex2);
}
finally
{
context.Request.Path = originalPath;
}
throw; // Re-throw the original if we couldn't handle it
}
}
}
}