Sitecore Identity reverse-proxy support

By default Sitecore Identity Server 9.1 does not support reverse-proxy forwarding. See this question at Sitecore Stack Exchange for details.

This plugin adds reverse-proxy support for the Sitecore Identity Server. It does this by injecting a small piece of ASP.NET Core middleware and by adding a PublicOrigin configuration option.

Applying the solution

To apply the solution:

• Build the project
• Copy the Sitecore.Identity.ProxySupport.dll assembly to C:\inetpub\wwwroot\identity\sitecoreruntime\production
• Copy Sitecore.Plugin.manifest and Config/ directory to C:\inetpub\wwwroot\identity\sitecoreruntime\production\sitecore\Sitecore.Identity.ProxySupport\
• As plugin load order is import, add Sitecore.Identity.ProxySupport as dependency to C:\inetpub\wwwroot\identity\sitecore\Sitecore.Plugin.IdentityServer\Sitecore.Plugin.manifest, e.g:

<?xml version="1.0" encoding="utf-8"?>
<SitecorePlugin PluginName="Sitecore.Plugin.IdentityServer" AssemblyName="Sitecore.Plugin.IdentityServer" Version="2.0.1-r00166">
  <Dependencies>
    <Dependency name="Sitecore.Plugin.IdentityProviders">2.0.1-r00166</Dependency>
    <Dependency name="Sitecore.Identity.ProxySupport"></Dependency>
  </Dependencies>
  <Tags>
    <Sitecore>Sitecore</Sitecore>
  </Tags>
</SitecorePlugin>

• Configure the PublicOrigin in config/proxysupport.xml

The above follows the standard way of working for a Sitecore Host plugin as defined here: https://doc.sitecore.com/developers/91/sitecore-experience-management/en/add-a-runtime-plugin-manually.html

NB. When you apply steps don't forget to stop the w3wp process

Credits

Special thanks to Per Bering for providing the code for this solution.