#498 import public data

GanjooRazor/Pages/Auth/Login.cshtml

@@ -44,7 +44,7 @@
             }
             else
             {
-                <form method="post" action="?handler=Login">
+                <form method="post" action="@("?handler=Login&redirect=" + Model.RedirectUrlEncoded)">
                     <table>
                         <tr>
                             <td>

GanjooRazor/Pages/Auth/Login.cshtml.cs

@@ -1,5 +1,6 @@
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.Extensions.Configuration;
+using System;
 using System.Net.Http;
 
 namespace GanjooRazor.Pages
@@ -15,6 +16,12 @@ namespace GanjooRazor.Pages
 
         public string RedirectUrl { get; set; }
 
+        /// <summary>
+        /// <see cref="RedirectUrl"/>, URL-encoded for embedding directly in the login form's
+        /// action attribute
+        /// </summary>
+        public string RedirectUrlEncoded => Uri.EscapeDataString(RedirectUrl);
+
         public void OnGet()
         {
             UserFriendlyName = Request.Cookies["Name"];

GanjooRazor/Pages/Index.cshtml.cs

@@ -5,6 +5,7 @@ using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using RMuseum.Models.Ganjoor.ViewModels;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net.Http;
 using System.Threading.Tasks;
 
@@ -139,11 +140,33 @@ namespace GanjooRazor.Pages
                 return Page();
             }
 
+            // A fresh/forked install has an empty (or nearly empty) database: no poets, or no
+            // century grouping yet. The view below assumes at least the "popular poets" group
+            // (Id == 0) exists — PoetGroups.Where(g => g.Id == 0).Single() — and throws on an
+            // empty database instead of rendering something useful. Steer the visitor toward
+            // fixing that instead of letting them hit an unhandled exception: log in first if
+            // needed, then straight to the admin page that can seed real content.
+            if (IsDatabaseEffectivelyEmpty())
+            {
+                const string targetUrl = "/Admin/PublicDataImport";
+                return LoggedIn ? Redirect(targetUrl) : Redirect($"/login?redirect={targetUrl}");
+            }
+
             ViewData["Title"] = "گنجور";
 
             return Page();
         }
 
+        /// <summary>
+        /// true if there's nothing meaningful to show on the home page yet — no poets at all, or
+        /// no century grouping (the "popular poets" group with Id == 0 that the view relies on).
+        /// </summary>
+        private bool IsDatabaseEffectivelyEmpty()
+        {
+            return Poets == null || Poets.Count == 0
+                || PoetGroups == null || !PoetGroups.Any(g => g.Id == 0);
+        }
+
         public async Task<IActionResult> OnGetPoetInformationAsync(int id)
         {
             if (id == 0)

GanjooRazor/Pages/LoginPartialEnabledPageModel.cs

@@ -208,8 +208,27 @@ namespace GanjooRazor.Pages
             }
             Response.Cookies.Append("CanTranslate", canTranlate.ToString(), cookieOption);
 
+            return Redirect(GetSafeRedirectTarget());
+        }
 
-            return Redirect(Request.Path);
+        /// <summary>
+        /// Resolves where to send the visitor after a successful login. Prefers the "redirect"
+        /// query string value (set by <see cref="LoginModel"/>'s form action so a login triggered
+        /// from /login?redirect=X lands on X afterward) over the previous default of always using
+        /// Request.Path, which just bounced back to the login page itself when login was posted
+        /// from there. Only accepts a local, root-relative path ("/..." and not "//..." or a
+        /// scheme — those are how open-redirect payloads look) to avoid the visitor's own
+        /// "redirect" query value being used to send them somewhere else entirely; anything else
+        /// falls back to the old behavior.
+        /// </summary>
+        private string GetSafeRedirectTarget()
+        {
+            string redirect = Request.Query["redirect"];
+            if (!string.IsNullOrEmpty(redirect) && redirect.StartsWith("/") && !redirect.StartsWith("//"))
+            {
+                return redirect;
+            }
+            return Request.Path;
         }
 
         public Task<IActionResult> OnGetCheckIfHasNotificationsAsync()