Request format is unrecognized for URL unexpectedly ending in '/Convert' happens after 1-2 days

Question

I'm calling a webservice using an Microsoft.XMLHTTP call:

var xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
xmlhttp.open("POST", "/xxx/Converter.asmx/Convert", false);
xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
xmlhttp.send("conversionFolder=" + escape(conversionFolder));
if (xmlhttp.status == 200) {
  xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
  xmlDoc.async = "false";
  xmlDoc.loadXML(xmlhttp.responseText);
  ... more stuff ...
  return str;
}
else {
  alert(xmlhttp.statusCode + " - " + xmlhttp.statusText);
}

It all works fine when I remember to add the HttpPost protocol in the local web.config:

<?xml version="1.0"?>
<configuration>
  <appSettings/>
  <connectionStrings/>
  <system.web>
    <webServices>
      <protocols>
        <add name="HttpPost"/>
      </protocols>
    </webServices>
    <compilation debug="false"></compilation>
  </system.web>
  <system.codedom>
  </system.codedom>
  <!--
    The system.webServer section is required for running ASP.NET AJAX under Internet
    Information Services 7.0.  It is not necessary for previous version of IIS.
  -->
  <system.webServer>
  </system.webServer>
</configuration>

But on one production server it fails after running for 1-2 days. It works fine after the asp.net process has been recycled. It works for 1-2 days and then it fails with this:

Exception information:
Exception type: InvalidOperationException
Exception message: Request format is unrecognized for URL unexpectedly ending in '/Convert'.

Request information:
Request URL: https://xxx/xxx/converter.asmx/Convert
Request path: /xxx/converter.asmx/Convert
User host address: 195.50.35.4
User: extranet\kbk
Is authenticated: True
Authentication Type:
Thread account name: NT AUTHORITY\NETWORK SERVICE

Thread information:
Thread ID: 14
Thread account name: NT AUTHORITY\NETWORK SERVICE
Is impersonating: False
Stack trace: at System.Web.Services.Protocols.WebServiceHandlerFactory.CoreGetHandler(Type type, HttpContext context, HttpRequest request, HttpResponse response)
at System.Web.Services.Protocols.WebServiceHandlerFactory.GetHandler(HttpContext context, String verb, String url, String filePath)
at System.Web.Script.Services.ScriptHandlerFactory.GetHandler(HttpContext context, String requestType, String url, String pathTranslated)
at System.Web.HttpApplication.MaterializeHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Why does it wait for 2 days before failing? And what can I do to prevent it from failing? Has it something to do with the fact that this server runs in HTTPS mode?

Answer 1

What is the Dot Net framework? IIS 6 or 7?
Have you tried adding <add name="HttpGet"/> in the protocols section. It seems some people have got over this problem with that fix. (but not for all)
link 1
link 2
Also check where you are deploying your site. Is it at the root level in your web server or a virtual folder. Sometimes it might be inheriting some configuration values from the parent level sites or machine.config file.

Otherwise it could be related to some memory leak in your code. What do you do with the loaded XML. Also I assume you are parsing a valid XML.

Answer 2

It seems there is an Hotfix available for when recycling the app pool fixxes the problem for a few days: http://support.microsoft.com/kb/2783777/en-us