29

Redbot报告我的网页的标题无效：

ETag 标头的语法无效。

我的标题设置为：

ETag: 4ae413bd

为什么无效？

ETag 的语法是什么？

4

4 回答 4

35

试试ETag: "4ae413bd"。ETag 的值必须遵循ABNF形式：

  entity-tag = [ weak ] opaque-tag
  weak       = "W/"
  opaque-tag = quoted-string

  quoted-string  = ( <"> *(qdtext | quoted-pair ) <"> )
  qdtext         = <any TEXT except <">>
  quoted-pair    = "\" CHAR
  CHAR           = <any US-ASCII character (octets 0 - 127)>
  TEXT           = <any OCTET except CTLs, but including LWS>
  OCTET          = <any 8-bit sequence of data>
  LWS            = [CRLF] 1*( SP | HT )
  CTL            = <any US-ASCII control character (octets 0 - 31) and DEL (127)>
  CRLF           = CR LF
  CR             = <US-ASCII CR, carriage return (13)>
  LF             = <US-ASCII LF, linefeed (10)>
  SP             = <US-ASCII SP, space (32)>
  HT             = <US-ASCII HT, horizontal-tab (9)>

，这基本上是([wW]/)?"([^"]|\\")*"在常规正则表达式中。

请注意，两者"\"都是"/"etag 的有效值。

参考文献：第 14.19节、第 3.11节、第 2.2 节。

于 2012-07-20T03:14:58.420 回答
13

正如 Arnaud 提到的，请确保您引用了该值。

代替

new EntityTagHeaderValue("0");

和

new EntityTagHeaderValue("\"0\"");
于 2015-02-17T21:37:14.127 回答
7

“ETag 是一个不透明的标识符，由 Web 服务器分配给在 URL 中找到的特定版本的资源”。这意味着它几乎可以是任何东西。

问题可能是语法，使用：

ETag: "4ae413bd"
于 2011-07-16T18:07:48.757 回答
2

如果您因为下面的堆栈跟踪而来到这里，请确保取消选中导致此错误的 Visual Studio 中的“启用浏览器链接”选项：取消选中此项

Conversion> [13:31:10 ERR] Connection id "0HLJ153E20LDJ", Request id "0HLJ153E20LDJ:00000003": An unhandled exception was thrown by the application.
Conversion> System.ObjectDisposedException: The response has been aborted due to an unhandled application exception. ---> System.FormatException: Invalid ETag name
Conversion>    at Microsoft.Net.Http.Headers.EntityTagHeaderValue..ctor(StringSegment tag, Boolean isWeak)
Conversion>    at Microsoft.Net.Http.Headers.EntityTagHeaderValue..ctor(StringSegment tag)
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.BrowserLinkMiddleWareUtil.AddToETag(ResponseHeaders responseHeader, Int32 port)
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.BrowserLinkMiddleware.<>c__DisplayClass7_0.<ExecuteWithFilter>b__0()
Conversion>    at Microsoft.AspNetCore.Http.HttpResponse.<>c.<.cctor>b__30_0(Object callback)
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.FireOnStartingMayAwait(Stack`1 onStarting)
Conversion>    --- End of inner exception stack trace ---
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ThrowResponseAbortedException()
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.InitializeResponseAsync(Int32 firstWriteByteCount)
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.WriteAsync(ReadOnlyMemory`1 data, CancellationToken cancellationToken)
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpResponseStream.WriteAsync(Byte[] buffer, Int32 offset, Int32 count, CancellationToken cancellationToken)
Conversion>    at System.IO.Stream.WriteAsync(Byte[] buffer, Int32 offset, Int32 count)
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.ScriptInjectionFilterStream.<>c__DisplayClass37_0.<<CreateResponseHandler>b__0>d.MoveNext()
Conversion> --- End of stack trace from previous location where exception was thrown ---
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.SocketReader.ReadBytesIntoResponseHandler(Int64 totalBytesToRead, ResponseHandler handler, CancellationToken cancellationToken)
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.HttpSocketAdapter.ResponseReader.ReadBytesIntoResponse(Int64 bytesToRead)
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.HttpSocketAdapter.ResponseReader.ReadChunkedContent()
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.HttpSocketAdapter.ResponseReader.ReadResponse()
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.DelayConnectingHttpSocketAdapter.Microsoft.VisualStudio.Web.BrowserLink.IHttpSocketAdapter.WaitForResponseComplete()
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.ScriptInjectionFilterStream.WaitForFilterComplete()
Conversion>    at Microsoft.VisualStudio.Web.BrowserLink.BrowserLinkMiddleware.ExecuteWithFilter(IHttpSocketAdapter injectScriptSocket, String requestId, HttpContext httpContext)
Conversion>    at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
Conversion>    at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
Conversion>    at Microsoft.AspNetCore.Server.IISIntegration.IISMiddleware.Invoke(HttpContext httpContext)
Conversion>    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
于 2018-12-13T22:15:17.897 回答