Added support for PathBase to be used behind a reverse proxy

src/Startup.cs

@@ -41,7 +41,11 @@ namespace SteamOpenIdConnectProvider
                     options.UserInteraction.LoginUrl = "/ExternalLogin";
                 })
                 .AddAspNetIdentity<IdentityUser>()
-                .AddInMemoryClients(IdentityServerConfig.GetClients(Configuration["OpenID:ClientID"], Configuration["OpenID:ClientSecret"], Configuration["OpenID:RedirectUri"], Configuration["OpenID:PostLogoutRedirectUri"]))
+                .AddInMemoryClients(IdentityServerConfig.GetClients(
+                    Configuration["OpenID:ClientID"], 
+                    Configuration["OpenID:ClientSecret"], 
+                    Configuration["OpenID:RedirectUri"], 
+                    Configuration["OpenID:PostLogoutRedirectUri"]))
                 .AddInMemoryPersistedGrants()
                 .AddDeveloperSigningCredential(true)
                 .AddInMemoryIdentityResources(IdentityServerConfig.GetIdentityResources());
@@ -63,6 +67,11 @@ namespace SteamOpenIdConnectProvider
                 app.UseDeveloperExceptionPage();
             }
 
+            if (!string.IsNullOrEmpty(Configuration["Hosting:PathBase"]))
+            {
+                app.UsePathBase(Configuration["Hosting:PathBase"]);
+            }
+
             app.UseRouting();
             app.UseIdentityServer();
             app.UseEndpoints(endpoints =>

src/appsettings.Development.json

@@ -5,5 +5,8 @@
       "System": "Information",
       "Microsoft": "Information"
     }
+  },
+  "Hosting": {
+    "PathBase": "/test"
   }
 }

src/appsettings.json

@@ -10,5 +10,8 @@
     "RedirectUri": "http://localhost:8080/auth/realms/master/broker/steam/endpoint",
     "PostLogoutRedirectUri": ""
   },
-  "AllowedHosts": "*"
+  "AllowedHosts": "*",
+  "Hosting": {
+    "PathBase": ""
+  }
 }