c# - IIS Express 8 - 最大允许长度

Question

万一以下内容太长，我的问题是 Visual Studio 2013 中的 IIS Express 8 是否遵守 maxAllowedContentLength 属性，或者它是否具有一些可防止大请求的覆盖值

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在针对 Visual Studio 2013 调试一些 webapi 调用时，我收到此错误:

超过最大请求长度。

我在网上搜索了一下，一切似乎都指向这两个配置条目:

IIS 6-: maxRequestLength
IIS 7+: maxAllowedContentLength

为了安全起见，我已将这两个配置条目添加到我的 web.config 中，值为 4294967295。当我尝试调用 Controller 时，我仍然收到错误。

这让我觉得我正在向服务器发送大量数据，但是 fiddler 告诉我:

Request Count:   1
Bytes Sent:      4,327,084      (headers:1,026; body:4,326,058)
Bytes Received:  3,808      (headers:434; body:3,374)

并且看到如何，4,327,084 < 4,294,967,295 我觉得这个请求应该没有任何问题。

我想到的下一个地方是我的服务器代码:

if (!Request.Content.IsMimeMultipartContent())
{
    throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType);
}

var provider = new MultipartFormDataStreamProvider(@"C:\tmp", Int32.MaxValue);

var task = Request.Content.ReadAsMultipartAsync(provider).ContinueWith(t =>
{
    if (t.IsFaulted || t.IsCanceled)
        throw t.Exception;   // <== This gets thrown

因此，请求的大小再次明显小于数据流提供程序的缓冲区大小。

总而言之，我不知道发生了什么。请求相当大，但据我所知，没有理由失败。这是由 VS13/IIS Exp8 引起的吗？还是我还缺少其他东西？

在此先感谢您提供的任何帮助。

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这是我说我会提供的配置条目

<requestLimits maxAllowedContentLength="4294967295" />

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这是完整的异常(exception)情况

System.IO.IOException: Error reading MIME multipart body part. ---> System.Web.HttpException: Maximum request length exceeded.
   at System.Web.HttpBufferlessInputStream.ValidateRequestEntityLength()
   at System.Web.HttpBufferlessInputStream.GetPreloadedContent(Byte[] buffer, Int32& offset, Int32& count)
   at System.Web.HttpBufferlessInputStream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state)
   at System.IO.Stream.<BeginEndReadAsync>b__d(Stream stream, ReadWriteParameters args, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncTrim[TInstance,TArgs](TInstance thisRef, TArgs args, Func`5 beginMethod, Func`3 endMethod)
   at System.IO.Stream.BeginEndReadAsync(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Stream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Web.Http.WebHost.SeekableBufferedRequestStream.<ReadAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()
   --- End of inner exception stack trace ---
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<ReadAsMultipartAsync>d__0`1.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at BICWeb.webservices.controllers.FormsDesignerController.<Post>d__b.MoveNext() in c:\code\BIC_CORE\TRUNK\BIC\src\BICWeb\webservices\controllers\FormsDesignerController.cs:line 300

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和内部异常

System.Web.HttpException (0x80004005): Maximum request length exceeded.
   at System.Web.HttpBufferlessInputStream.ValidateRequestEntityLength()
   at System.Web.HttpBufferlessInputStream.GetPreloadedContent(Byte[] buffer, Int32& offset, Int32& count)
   at System.Web.HttpBufferlessInputStream.BeginRead(Byte[] buffer, Int32 offset, Int32 count, AsyncCallback callback, Object state)
   at System.IO.Stream.<BeginEndReadAsync>b__d(Stream stream, ReadWriteParameters args, AsyncCallback callback, Object state)
   at System.Threading.Tasks.TaskFactory`1.FromAsyncTrim[TInstance,TArgs](TInstance thisRef, TArgs args, Func`5 beginMethod, Func`3 endMethod)
   at System.IO.Stream.BeginEndReadAsync(Byte[] buffer, Int32 offset, Int32 count)
   at System.IO.Stream.ReadAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
   at System.Web.Http.WebHost.SeekableBufferedRequestStream.<ReadAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Net.Http.HttpContentMultipartExtensions.<MultipartReadAsync>d__8.MoveNext()

Answer 1

让我们看看抛出的代码:

private void ValidateRequestEntityLength()
{
    if (!this._disableMaxRequestLength && (this.Length > this._maxRequestLength))
    {
        if (!(this._context.WorkerRequest is IIS7WorkerRequest))
        {
            this._context.Response.CloseConnectionAfterError();
        }
        throw new HttpException(SR.GetString("Max_request_length_exceeded"), null, 0xbbc);
    }
}

构造函数设置这些选项:

internal HttpBufferlessInputStream(HttpContext context, bool persistEntityBody, bool disableMaxRequestLength)
{
    this._context = context;
    this._persistEntityBody = persistEntityBody;
    this._disableMaxRequestLength = disableMaxRequestLength;
    HttpRuntimeSection httpRuntime = RuntimeConfig.GetConfig(this._context).HttpRuntime;
    this._maxRequestLength = httpRuntime.MaxRequestLengthBytes;
    this._fileThreshold = httpRuntime.RequestLengthDiskThresholdBytes;
    if (this._persistEntityBody)
    {
        this._rawContent = new HttpRawUploadedContent(this._fileThreshold, this._context.Request.ContentLength);
    }
    int contentLength = this._context.Request.ContentLength;
    this._remainingBytes = (contentLength > 0) ? contentLength : 0x7fffffff;
    this._length = contentLength;
}

您可以使用此 HttpRequest 函数来禁用限制:

public Stream GetBufferlessInputStream(bool disableMaxRequestLength)
{
    return this.GetInputStream(false, disableMaxRequestLength);
}

如果您想知道字节限制是如何计算的，反编译httpRuntime.MaxRequestLengthBytes。