IIS DelegatingHandler 被覆盖

Question

我为我的 IIS 托管的 WebAPI 创建了一个 DelegatingHandler，如果响应代码是 405，它会创建一个自定义响应。

此代码被执行，并且没有注册其他处理程序。 我通过调试和日志记录验证了这一点。

但是，我最终得到的响应是通用的 html 代码。 就好像我的回复被 IIS 不知何故覆盖了。

有人可以指出什么处理程序会产生此响应：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<title>IIS 10.0 Detailed Error - 405.0 - Method Not Allowed</title> 
<style type="text/css"> 
<!-- 
body{margin:0;font-size:.7em;font-family:Verdana,Arial,Helvetica,sans-serif;} 
code{margin:0;color:#006600;font-size:1.1em;font-weight:bold;} 
.config_source code{font-size:.8em;color:#000000;} 
pre{margin:0;font-size:1.4em;word-wrap:break-word;} 
ul,ol{margin:10px 0 10px 5px;} 
ul.first,ol.first{margin-top:5px;} 
fieldset{padding:0 15px 10px 15px;word-break:break-all;} 
.summary-container fieldset{padding-bottom:5px;margin-top:4px;} 
legend.no-expand-all{padding:2px 15px 4px 10px;margin:0 0 0 -12px;} 
legend{color:#333333;;margin:4px 0 8px -12px;_margin-top:0px; 
font-weight:bold;font-size:1em;} 
a:link,a:visited{color:#007EFF;font-weight:bold;} 
a:hover{text-decoration:none;} 
h1{font-size:2.4em;margin:0;color:#FFF;} 
h2{font-size:1.7em;margin:0;color:#CC0000;} 
h3{font-size:1.4em;margin:10px 0 0 0;color:#CC0000;} 
h4{font-size:1.2em;margin:10px 0 5px 0; 
}#header{width:96%;margin:0 0 0 0;padding:6px 2% 6px 2%;font-family:"trebuchet MS",Verdana,sans-serif; 
 color:#FFF;background-color:#5C87B2; 
}#content{margin:0 0 0 2%;position:relative;} 
.summary-container,.content-container{background:#FFF;width:96%;margin-top:8px;padding:10px;position:relative;} 
.content-container p{margin:0 0 10px 0; 
}#details-left{width:35%;float:left;margin-right:2%; 
}#details-right{width:63%;float:left;overflow:hidden; 
}#server_version{width:96%;_height:1px;min-height:1px;margin:0 0 5px 0;padding:11px 2% 8px 2%;color:#FFFFFF; 
 background-color:#5A7FA5;border-bottom:1px solid #C1CFDD;border-top:1px solid #4A6C8E;font-weight:normal; 
 font-size:1em;color:#FFF;text-align:right; 
}#server_version p{margin:5px 0;} 
table{margin:4px 0 4px 0;width:100%;border:none;} 
td,th{vertical-align:top;padding:3px 0;text-align:left;font-weight:normal;border:none;} 
th{width:30%;text-align:right;padding-right:2%;font-weight:bold;} 
thead th{background-color:#ebebeb;width:25%; 
}#details-right th{width:20%;} 
table tr.alt td,table tr.alt th{} 
.highlight-code{color:#CC0000;font-weight:bold;font-style:italic;} 
.clear{clear:both;} 
.preferred{padding:0 5px 2px 5px;font-weight:normal;background:#006633;color:#FFF;font-size:.8em;} 
--> 
</style> 
 
</head> 
<body> 
<div id="content"> 
<div class="content-container"> 
  <h3>HTTP Error 405.0 - Method Not Allowed</h3> 
  <h4>The page you are looking for cannot be displayed because an invalid method (HTTP verb) is being used.</h4> 
</div> 
<div class="content-container"> 
 <fieldset><h4>Most likely causes:</h4> 
  <ul>  <li>The request sent to the Web server used an HTTP verb that is not allowed by the module configured to handle the request.</li>   <li>A request was sent to the server that contained an invalid HTTP verb.</li>  <li>The request is for static content and contains an HTTP verb other than GET or HEAD.</li>    <li>A request was sent to a virtual directory using the HTTP verb POST and the default document is a static file that does not support HTTP verbs other than GET or HEAD.</li> </ul> 
 </fieldset> 
</div> 
<div class="content-container"> 
 <fieldset><h4>Things you can try:</h4> 
  <ul>  <li>Verify the list of verbs enabled for the module handler this request was sent to, and ensure that this verb should be allowed for the Web site.</li>    <li>Check the IIS log file to see which verb is not allowed for the request.</li>   <li>Create a tracing rule to track failed requests for this HTTP status code. For more information about creating a tracing rule for failed requests, click <a href="http://go.microsoft.com/fwlink/?LinkID=66439">here</a>. </li> </ul> 
 </fieldset> 
</div> 
 
<div class="content-container"> 
 <fieldset><h4>Detailed Error Information:</h4> 
  <div id="details-left"> 
   <table border="0" cellpadding="0" cellspacing="0"> 
    <tr class="alt"><th>Module</th><td>&nbsp;&nbsp;&nbsp;ManagedPipelineHandler</td></tr> 
    <tr><th>Notification</th><td>&nbsp;&nbsp;&nbsp;ExecuteRequestHandler</td></tr> 
    <tr class="alt"><th>Handler</th><td>&nbsp;&nbsp;&nbsp;System.Web.Http.WebHost.HttpControllerHandler</td></tr> 
    <tr><th>Error Code</th><td>&nbsp;&nbsp;&nbsp;0x00000000</td></tr> 
     
   </table> 
  </div> 
  <div id="details-right"> 
   <table border="0" cellpadding="0" cellspacing="0"> 
    <tr class="alt"><th>Requested URL</th><td>&nbsp;&nbsp;&nbsp;http://127.0.0.1:8002/deradapter/tm</td></tr> 
    <tr><th>Physical Path</th><td>&nbsp;&nbsp;&nbsp;c:\inetpub\VHOST\TDMSWebIEEE20305Site\DerAdapter\tm</td></tr> 
    <tr class="alt"><th>Logon Method</th><td>&nbsp;&nbsp;&nbsp;Anonymous</td></tr> 
    <tr><th>Logon User</th><td>&nbsp;&nbsp;&nbsp;Anonymous</td></tr> 
     
   </table> 
   <div class="clear"></div> 
  </div> 
 </fieldset> 
</div> 
 
<div class="content-container"> 
 <fieldset><h4>More Information:</h4> 
  This error means that the request sent to the Web server contained an HTTP verb that is not allowed by the configured module handler for the request. 
  <p><a href="https://go.microsoft.com/fwlink/?LinkID=62293&amp;IIS70Error=405,0,0x00000000,17763">View more information &raquo;</a></p> 
   
 </fieldset> 
</div> 
</div> 
</body> 
</html> 

处理程序的代码非常简单：

protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
        {
            var result = await base.SendAsync(request, cancellationToken);

            if (result.StatusCode != HttpStatusCode.MethodNotAllowed)
            {
                return result;
            }

            result.Content = GetResultContent(); //This is the method that simply creates a customized message
            result.Content.Headers.ContentType = new MediaTypeHeaderValue("application/sep+xml");
            return result;
        }

处理程序注册如下：

config.MessageHandlers.Add(new MethodNotAllowedHandler());

没有其他处理程序。

Answer 1

解决我的问题的方法是将其添加到 web.config 中：

<system.webServer>
<httpErrors existingResponse="Passthrough" />
</system.webServer>

我在这个链接上找到了这个。

我是通过从Richard Deeming的评论中获得的一个线程来实现的，所以谢谢你。

基本上，我需要 IIS 来不处理从我的 WebAPI 收到的错误，而这个配置设置就是这样告诉它的。