What IIS handler mappings must be set for IIS to work with web api 2?

Question

I get a 500 error when trying to POST a new record using IIS.

The PUT works, the GET works, only the POST results in 500 server error.

I do NOT get an error when using IISExpress in Visual Studio.

This just throws in my local IIS web server only.

The handler mappings in many cases have a list of VERBS they will accept and by default many of them exclude the POST verb.

Seems clear to me this is where my problem is located.

I don't want to go through each and every one guessing.

There must be a problem in the handler mappings, but I don't know what handler mappings must be set.

Can this be done in my application web config instead of configuring IIS?

<modules runAllManagedModulesForAllRequests="true">
  <remove name="WebDAVModule"/>
</modules>

<handlers accessPolicy="Read, Script">
        <remove name="WebDAV" />
  <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
  <remove name="OPTIONSVerbHandler" />
  <remove name="TRACEVerbHandler" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />
  <!--add name="WebDAV" path="*" verb="*" modules="WebDAVModule" resourceType="Unspecified" requireAccess="None" /-->
</handlers>

How can I edit or config IIS to give me more details?

Answer 1

Here are the basic handlers for Web Api 2.0.

<system.webServer>
    <validation validateIntegratedModeConfiguration="false"/>
    <modules runAllManagedModulesForAllRequests="true"/>
    <handlers>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_32bit"/>
      <remove name="ExtensionlessUrlHandler-ISAPI-4.0_64bit"/>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0"/>
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_32bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness32" responseBufferLimit="0"/>
      <add name="ExtensionlessUrlHandler-ISAPI-4.0_64bit" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" modules="IsapiModule" scriptProcessor="%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_isapi.dll" preCondition="classicMode,runtimeVersionv4.0,bitness64" responseBufferLimit="0"/>
      <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="GET,HEAD,POST,DEBUG,PUT,DELETE,PATCH,OPTIONS" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0"/>
    </handlers>
  </system.webServer>

Also, just to be sure, you should post the exception message with that 500 error. I am sure you will find something a little more detailed.

Also, you may need to tell IIS to return a little more detailed information. You normally would do that by adding the below entry to your we.config's config section.

  <system.web>
    <customErrors mode="Off"/>
    <compilation debug="true"/>
  </system.web>