I have a .net 5.0 preview 7 project running Blazor server, and Identity login was working fine, until I scaffolded the Identity Login page. Now I get The returnUrl field is required.
form error message as soon as the login page loads
When I debug OnGetAsync
method in Login.cshtml.cs, it shows that returnUrl does have a value.
I have <Nullable>enable</Nullable>
in csproj in case that could make a difference.
Here's the Login.cshtml.cs and Login.cshtml file content exactly as scaffolded, and causing the issue. Any ideas what could be wrong?
// Login.cshtml.cs
using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Identity.UI.Services;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;
using POS.WebAdmin.Data.Model;
namespace POS.WebAdmin.Areas.Identity.Pages.Account
{
[AllowAnonymous]
public class LoginModel : PageModel
{
private readonly UserManager<ApplicationUser> _userManager;
private readonly SignInManager<ApplicationUser> _signInManager;
private readonly ILogger<LoginModel> _logger;
public LoginModel(SignInManager<ApplicationUser> signInManager,
ILogger<LoginModel> logger,
UserManager<ApplicationUser> userManager)
{
_userManager = userManager;
_signInManager = signInManager;
_logger = logger;
}
[BindProperty]
public InputModel Input { get; set; }
public IList<AuthenticationScheme> ExternalLogins { get; set; }
public string ReturnUrl { get; set; }
[TempData]
public string ErrorMessage { get; set; }
public class InputModel
{
[Required]
[EmailAddress]
public string Email { get; set; }
[Required]
[DataType(DataType.Password)]
public string Password { get; set; }
[Display(Name = "Remember me?")]
public bool RememberMe { get; set; }
}
public async Task OnGetAsync(string returnUrl = null)
{
if (!string.IsNullOrEmpty(ErrorMessage))
{
ModelState.AddModelError(string.Empty, ErrorMessage);
}
returnUrl = returnUrl ?? Url.Content("~/");
// Clear the existing external cookie to ensure a clean login process
await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);
ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();
ReturnUrl = returnUrl;
}
public async Task<IActionResult> OnPostAsync(string returnUrl = null)
{
returnUrl = returnUrl ?? Url.Content("~/");
ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();
if (ModelState.IsValid)
{
// This doesn't count login failures towards account lockout
// To enable password failures to trigger account lockout, set lockoutOnFailure: true
var result = await _signInManager.PasswordSignInAsync(Input.Email, Input.Password, Input.RememberMe, lockoutOnFailure: false);
if (result.Succeeded)
{
_logger.LogInformation("User logged in.");
return LocalRedirect(returnUrl);
}
if (result.RequiresTwoFactor)
{
return RedirectToPage("./LoginWith2fa", new { ReturnUrl = returnUrl, RememberMe = Input.RememberMe });
}
if (result.IsLockedOut)
{
_logger.LogWarning("User account locked out.");
return RedirectToPage("./Lockout");
}
else
{
ModelState.AddModelError(string.Empty, "Invalid login attempt.");
return Page();
}
}
// If we got this far, something failed, redisplay form
return Page();
}
}
}
// Login.cshtml
@page
@model LoginModel
@{
ViewData["Title"] = "Log in";
}
<h1>@ViewData["Title"]</h1>
<div class="row">
<div class="col-md-4">
<section>
<form id="account" method="post">
<h4>Use a local account to log in.</h4>
<hr />
<div asp-validation-summary="All" class="text-danger"></div>
<div class="form-group">
<label asp-for="Input.Email"></label>
<input asp-for="Input.Email" class="form-control" />
<span asp-validation-for="Input.Email" class="text-danger"></span>
</div>
<div class="form-group">
<label asp-for="Input.Password"></label>
<input asp-for="Input.Password" class="form-control" />
<span asp-validation-for="Input.Password" class="text-danger"></span>
</div>
<div class="form-group">
<div class="checkbox">
<label asp-for="Input.RememberMe">
<input asp-for="Input.RememberMe" />
@Html.DisplayNameFor(m => m.Input.RememberMe)
</label>
</div>
</div>
<div class="form-group">
<button type="submit" class="btn btn-primary">Log in</button>
</div>
<div class="form-group">
<p>
<a id="forgot-password" asp-page="./ForgotPassword">Forgot your password?</a>
</p>
<p>
<a asp-page="./Register" asp-route-returnUrl="@Model.ReturnUrl">Register as a new user</a>
</p>
<p>
<a id="resend-confirmation" asp-page="./ResendEmailConfirmation">Resend email confirmation</a>
</p>
</div>
</form>
</section>
</div>
<div class="col-md-6 col-md-offset-2">
<section>
<h4>Use another service to log in.</h4>
<hr />
@{
if ((Model.ExternalLogins?.Count ?? 0) == 0)
{
<div>
<p>
There are no external authentication services configured. See <a href="https://go.microsoft.com/fwlink/?LinkID=532715">this article</a>
for details on setting up this ASP.NET application to support logging in via external services.
</p>
</div>
}
else
{
<form id="external-account" asp-page="./ExternalLogin" asp-route-returnUrl="@Model.ReturnUrl" method="post" class="form-horizontal">
<div>
<p>
@foreach (var provider in Model.ExternalLogins)
{
<button type="submit" class="btn btn-primary" name="provider" value="@provider.Name" title="Log in using your @provider.DisplayName account">@provider.DisplayName</button>
}
</p>
</div>
</form>
}
}
</section>
</div>
</div>
@section Scripts {
<partial name="_ValidationScriptsPartial" />
}
Finally found the solution here
Changing the OnGetAsync returnUrl
parameter to nullable solves the issue:
from
public async Task OnGetAsync(string returnUrl = null)
to
public async Task OnGetAsync(string? returnUrl = null)