Azure webapp Web.config httpErrors not redirecting

Question

I have an Azure-hosted website that is working great. The thing I'm stuck on is a desire to ignore anything after the base URL, and always have the user see the single page that is the whole site. (If they type the http://example.com site, anything after that will be ignored, and my map.html page will be shown.

I have made the following changes to the Web.config file, which help this along:

<system.webServer>
  <defaultDocument enabled="true">
    <files>
      <clear />
      <add value="map.html" />
    </files>
  </defaultDocument>
  <httpErrors errorMode="Custom" defaultResponseMode="ExecuteURL">
    <remove statusCode="404" subStatusCode="-1" />
    <error statusCode="404 path="/map.html" responseMode="ExecuteURL" />
  </httpErrors>
</system.webServer>

If I enter a url of example.com/xxxx.yyyy the site displays fine (it ignores the "/xxxx.yyyy" and shows the map.html page - just what I want. But if I enter example.com/xxxx without the trailing ".yyyy") the following IIS or Azure message shows:

Server Error in '/' Application.
The resource cannot be found.
Description: HTTP 404 The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporally unavailable...
Requested URL: /xxxx

How can I get the same redirect to happen no matter what follows the site name in the url?

I've tried Windows Edge, Chrome, and Safari, and they all give the same results.

Answer 1

To achieve your requirement, you can add a rewrite rule instead:

<system.webServer>
  <rewrite>
    <rules>
      <rule name="Rewrite to map">
        <action type="Rewrite" url="/map.html"/>
      </rule>
    </rules>
  </rewrite>

---

Update:

If you work in ASP.NET, you may also need to specify <customErrors> Element in Web.config:

<?xml version="1.0" encoding="UTF-8"?>

<configuration>
  <system.web>
    <customErrors mode="On">
      <error statusCode="404" redirect="~/map.html" />
    </customErrors>
  </system.web>

  <system.webServer>
    <defaultDocument enabled="true">
      <files>
        <clear />
        <add value="map.html" />
      </files>
    </defaultDocument>
    <httpErrors errorMode="Custom" defaultResponseMode="ExecuteURL">
      <remove statusCode="404" subStatusCode="-1" />
      <error statusCode="404" path="/map.html" responseMode="ExecuteURL" />
    </httpErrors>
  </system.webServer>
</configuration>