92 lines
3.5 KiB
C#
92 lines
3.5 KiB
C#
// Copyright (c) .NET Foundation. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using System.Threading.Tasks;
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using Microsoft.AspNet.Builder;
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using Microsoft.AspNet.Http;
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using Microsoft.AspNet.Http.Features;
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using Microsoft.Framework.Logging;
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using Microsoft.Net.Http.Headers;
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namespace Microsoft.AspNet.Diagnostics
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{
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public class ExceptionHandlerMiddleware
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{
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private readonly RequestDelegate _next;
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private readonly ExceptionHandlerOptions _options;
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private readonly ILogger _logger;
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private readonly Func<object, Task> _clearCacheHeadersDelegate;
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public ExceptionHandlerMiddleware(RequestDelegate next, ILoggerFactory loggerFactory, ExceptionHandlerOptions options)
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{
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_next = next;
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_options = options;
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_logger = loggerFactory.CreateLogger<ExceptionHandlerMiddleware>();
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if (_options.ExceptionHandler == null)
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{
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_options.ExceptionHandler = _next;
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}
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_clearCacheHeadersDelegate = ClearCacheHeaders;
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}
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public async Task Invoke(HttpContext context)
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{
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try
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{
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await _next(context);
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}
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catch (Exception ex)
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{
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_logger.LogError("An unhandled exception has occurred: " + ex.Message, ex);
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// We can't do anything if the response has already started, just abort.
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if (context.Response.HasStarted)
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{
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_logger.LogWarning("The response has already started, the error handler will not be executed.");
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throw;
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}
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PathString originalPath = context.Request.Path;
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if (_options.ExceptionHandlingPath.HasValue)
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{
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context.Request.Path = _options.ExceptionHandlingPath;
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}
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try
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{
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context.Response.Clear();
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var exceptionHandlerFeature = new ExceptionHandlerFeature()
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{
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Error = ex,
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};
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context.Features.Set<IExceptionHandlerFeature>(exceptionHandlerFeature);
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context.Response.StatusCode = 500;
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context.Response.OnStarting(_clearCacheHeadersDelegate, context.Response);
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await _options.ExceptionHandler(context);
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// TODO: Optional re-throw? We'll re-throw the original exception by default if the error handler throws.
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return;
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}
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catch (Exception ex2)
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{
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// Suppress secondary exceptions, re-throw the original.
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_logger.LogError("An exception was thrown attempting to execute the error handler.", ex2);
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}
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finally
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{
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context.Request.Path = originalPath;
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}
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throw; // Re-throw the original if we couldn't handle it
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}
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}
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private Task ClearCacheHeaders(object state)
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{
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var response = (HttpResponse)state;
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response.Headers[HeaderNames.CacheControl] = "no-cache";
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response.Headers[HeaderNames.Pragma] = "no-cache";
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response.Headers[HeaderNames.Expires] = "-1";
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response.Headers.Remove(HeaderNames.ETag);
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return Task.FromResult(0);
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}
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}
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} |