Edge case: Can you configure Net.Core 3.1 to run in the same folder as Asp.Classic?

I am looking at migrating a huge Asp.Classic (3K files) to Net.Core 3.1 in steps (i.e. folder by folder migration). We have figured out issues with sharing sessions and prefer not to go parallel sites (but may end going there if there is not a simple solution).

One line (in <-- --> below) in a merged Web.Config determines if Asp.Classic loads or Net.Core loads.

Commented out: Asp.Classic
Uncomment: Net.Core

    <system.webServer>
        <validation validateIntegratedModeConfiguration="false" />
      <handlers>
        <!--<add name="aspNetCore" path="*" verb="*" modules="AspNetCoreModuleV2" resourceType="Unspecified" />-->
      </handlers>
        <aspNetCore processPath="dotnet" arguments=".\WebApplication1.dll" stdoutLogEnabled="false" stdoutLogFile=".\logs\stdout" hostingModel="inprocess" />
    </system.webServer>

I realize that ISAPI filter written in C++ is a possibility (in one way easy: if there is an .asp in the request go to Asp.Classic, otherwise pass to Net.Core). Any alternatives before walking that path?

Solution

As far as I know, if you want to host classic asp and asp.net core at same IIS web site, you should modify your hanlder mapping to make the classic asp handler above the asp.net core module.

Details, you could refer to below steps:

1.Open the IIS management console and select handler mapping:

2.Click the ordered list:

3.Move the classic asp up than the aspnet core