Improve email settings validation and UX (#3891)

BTCPayServer.Client/Models/EmailSettingsData.cs

@@ -1,4 +1,4 @@
-namespace BTCPayServer.Client.Models;
+namespace BTCPayServer.Client.Models;
 
 public class EmailSettingsData
 {
@@ -21,11 +21,6 @@ public class EmailSettingsData
     {
         get; set;
     }
-
-    public string FromDisplay
-    {
-        get; set;
-    }
     public string From
     {
         get; set;

BTCPayServer.Tests/SeleniumTests.cs

@@ -1940,6 +1940,7 @@ retry:
             s.Driver.FindElement(By.CssSelector("button[value=\"Save\"]")).Submit();
             s.FindAlertMessage();
             s.Driver.FindElement(By.Id("Settings_Password")).SendKeys("mypassword");
+            s.Driver.FindElement(By.Id("Settings_From")).SendKeys("Firstname Lastname <email@example.com>");
             s.Driver.FindElement(By.Id("Save")).SendKeys(Keys.Enter);
             Assert.Contains("Configured", s.Driver.PageSource);
             s.Driver.FindElement(By.Id("Settings_Login")).SendKeys("test_fix@gmail.com");

BTCPayServer/Controllers/GreenField/GreenfieldStoreEmailController.cs

@@ -39,7 +39,7 @@ namespace BTCPayServer.Controllers.GreenField
             {
                 return this.CreateAPIError(404, "store-not-found", "The store was not found");
             }
-            if (!MailboxAddress.TryParse(request.Email, out MailboxAddress to))
+            if (!MailboxAddressValidator.TryParse(request.Email, out var to))
             {
                 ModelState.AddModelError(nameof(request.Email), "Invalid email");
                 return this.CreateValidationError(ModelState);
@@ -72,7 +72,7 @@ namespace BTCPayServer.Controllers.GreenField
                 return StoreNotFound();
             }
 
-            if (!string.IsNullOrEmpty(request.From) && !EmailValidator.IsEmail(request.From))
+            if (!string.IsNullOrEmpty(request.From) && !MailboxAddressValidator.IsMailboxAddress(request.From))
             {
                 request.AddModelError(e => e.From,
                     "Invalid email address", this);

BTCPayServer/Controllers/GreenField/GreenfieldUsersController.cs

@@ -118,7 +118,7 @@ namespace BTCPayServer.Controllers.Greenfield
         {
             if (request.Email is null)
                 ModelState.AddModelError(nameof(request.Email), "Email is missing");
-            if (!string.IsNullOrEmpty(request.Email) && !Validation.EmailValidator.IsEmail(request.Email))
+            if (!string.IsNullOrEmpty(request.Email) && !MailboxAddressValidator.IsMailboxAddress(request.Email))
             {
                 ModelState.AddModelError(nameof(request.Email), "Invalid email");
             }

BTCPayServer/Controllers/UIInvoiceController.cs

@@ -233,7 +233,7 @@ namespace BTCPayServer.Controllers
 
             if (entity.Metadata.BuyerEmail != null)
             {
-                if (!EmailValidator.IsEmail(entity.Metadata.BuyerEmail))
+                if (!MailboxAddressValidator.IsMailboxAddress(entity.Metadata.BuyerEmail))
                     throw new BitpayHttpException(400, "Invalid email");
                 entity.RefundMail = entity.Metadata.BuyerEmail;
             }

BTCPayServer/Controllers/UIManageController.cs

@@ -165,8 +165,7 @@ namespace BTCPayServer.Controllers
 
             var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
             var callbackUrl = _linkGenerator.EmailConfirmationLink(user.Id, code, Request.Scheme, Request.Host, Request.PathBase);
-            var address = new MailboxAddress(user.UserName, user.Email);
+            (await _EmailSenderFactory.GetEmailSender()).SendEmailConfirmation(user.GetMailboxAddress(), callbackUrl);
-            (await _EmailSenderFactory.GetEmailSender()).SendEmailConfirmation(address, callbackUrl);
             TempData[WellKnownTempData.SuccessMessage] = "Verification email sent. Please check your email.";
             return RedirectToAction(nameof(Index));
         }

BTCPayServer/Controllers/UIServerController.Users.cs

@@ -303,8 +303,7 @@ namespace BTCPayServer.Controllers
             var code = await _UserManager.GenerateEmailConfirmationTokenAsync(user);
             var callbackUrl = _linkGenerator.EmailConfirmationLink(user.Id, code, Request.Scheme, Request.Host, Request.PathBase);
 
-            var address = new MailboxAddress(user.UserName, user.Email);
+            (await _emailSenderFactory.GetEmailSender()).SendEmailConfirmation(user.GetMailboxAddress(), callbackUrl);
-            (await _emailSenderFactory.GetEmailSender()).SendEmailConfirmation(address, callbackUrl);
 
             TempData[WellKnownTempData.SuccessMessage] = "Verification email sent";
             return RedirectToAction(nameof(ListUsers));

BTCPayServer/Controllers/UIServerController.cs

@@ -1,6 +1,7 @@
 #nullable enable
 using System;
 using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
 using System.Diagnostics.CodeAnalysis;
 using System.Globalization;
 using System.IO;
@@ -25,6 +26,7 @@ using BTCPayServer.Services.Stores;
 using BTCPayServer.Storage.Models;
 using BTCPayServer.Storage.Services;
 using BTCPayServer.Storage.Services.Providers;
+using BTCPayServer.Validation;
 using Microsoft.AspNetCore.Authorization;
 using Microsoft.AspNetCore.Identity;
 using Microsoft.AspNetCore.Mvc;
@@ -1015,18 +1017,13 @@ namespace BTCPayServer.Controllers
                         var settings = await _SettingsRepository.GetSettingAsync<EmailSettings>() ?? new EmailSettings();
                         model.Settings.Password = settings.Password;
                     }
-                    if (!model.Settings.IsComplete())
+                    model.Settings.Validate("Settings.", ModelState);
-                    {
+                    if (string.IsNullOrEmpty(model.TestEmail))
-                        TempData[WellKnownTempData.ErrorMessage] = "Required fields missing";
+                        ModelState.AddModelError(nameof(model.TestEmail), new RequiredAttribute().FormatErrorMessage(nameof(model.TestEmail)));
+                    if (!ModelState.IsValid)
                         return View(model);
-                    }
-                    if (!MailboxAddress.TryParse(model.TestEmail, out MailboxAddress testEmail))
-                    {
-                        TempData[WellKnownTempData.ErrorMessage] = "Invalid test email";
-                        return View(model);
-                    }
                     using (var client = await model.Settings.CreateSmtpClient())
-                    using (var message = model.Settings.CreateMailMessage(testEmail, "BTCPay test", "BTCPay test", false))
+                    using (var message = model.Settings.CreateMailMessage(MailboxAddress.Parse(model.TestEmail), "BTCPay test", "BTCPay test", false))
                     {
                         await client.SendAsync(message);
                         await client.DisconnectAsync(true);
@@ -1043,12 +1040,17 @@ namespace BTCPayServer.Controllers
             {
                 var settings = await _SettingsRepository.GetSettingAsync<EmailSettings>() ?? new EmailSettings();
                 settings.Password = null;
-                await _SettingsRepository.UpdateSetting(model.Settings);
+                await _SettingsRepository.UpdateSetting(settings);
                 TempData[WellKnownTempData.SuccessMessage] = "Email server password reset";
                 return RedirectToAction(nameof(Emails));
             }
             else // if (command == "Save")
             {
+                if (model.Settings.From is not null && !MailboxAddressValidator.IsMailboxAddress(model.Settings.From))
+                {
+                    ModelState.AddModelError("Settings.From", "Invalid email");
+                    return View(model);
+                }
                 var oldSettings = await _SettingsRepository.GetSettingAsync<EmailSettings>() ?? new EmailSettings();
                 if (new EmailsViewModel(oldSettings).PasswordSet)
                 {

BTCPayServer/Controllers/UIStoresController.Email.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using System.Globalization;
 using System.Threading.Tasks;
 using BTCPayServer.Abstractions.Constants;
 using BTCPayServer.Abstractions.Extensions;
@@ -45,7 +46,7 @@ namespace BTCPayServer.Controllers
             if (command.StartsWith("remove", StringComparison.InvariantCultureIgnoreCase))
             {
                 var item = command[(command.IndexOf(":", StringComparison.InvariantCultureIgnoreCase) + 1)..];
-                var index = int.Parse(item);
+                var index = int.Parse(item, CultureInfo.InvariantCulture);
                 vm.Rules.RemoveAt(index);
                 
                 return View(vm);
@@ -117,18 +118,13 @@ namespace BTCPayServer.Controllers
                     {
                         model.Settings.Password = store.GetStoreBlob().EmailSettings.Password;
                     }
-                    if (!model.Settings.IsComplete())
+                    model.Settings.Validate("Settings.", ModelState);
-                    {
+                    if (string.IsNullOrEmpty(model.TestEmail))
-                        TempData[WellKnownTempData.ErrorMessage] = "Required fields missing";
+                        ModelState.AddModelError(nameof(model.TestEmail), new RequiredAttribute().FormatErrorMessage(nameof(model.TestEmail)));
+                    if (!ModelState.IsValid)
                         return View(model);
-                    }
-                    if (!MailboxAddress.TryParse(model.TestEmail, out MailboxAddress testEmail))
-                    {
-                        TempData[WellKnownTempData.ErrorMessage] = "Invalid test email";
-                        return View(model);
-                    }
                     using var client = await model.Settings.CreateSmtpClient();
-                    var message = model.Settings.CreateMailMessage(testEmail, "BTCPay test", "BTCPay test", false);
+                    var message = model.Settings.CreateMailMessage(MailboxAddress.Parse(model.TestEmail), "BTCPay test", "BTCPay test", false);
                     await client.SendAsync(message);
                     await client.DisconnectAsync(true);
                     TempData[WellKnownTempData.SuccessMessage] = $"Email sent to {model.TestEmail}. Please verify you received it.";
@@ -150,6 +146,11 @@ namespace BTCPayServer.Controllers
             }
             else // if (command == "Save")
             {
+                if (model.Settings.From is not null && !MailboxAddressValidator.IsMailboxAddress(model.Settings.From))
+                {
+                    ModelState.AddModelError("Settings.From", "Invalid email");
+                    return View(model);
+                }
                 var storeBlob = store.GetStoreBlob();
                 if (new EmailsViewModel(storeBlob.EmailSettings).PasswordSet && storeBlob.EmailSettings != null)
                 {

BTCPayServer/Data/Payouts/LightningLike/LightningLikePayoutHandler.cs

@@ -64,7 +64,7 @@ namespace BTCPayServer.Data.Payouts.LightningLike
             try
             {
                 string lnurlTag = null;
-                var lnurl = EmailValidator.IsEmail(destination)
+                var lnurl = MailboxAddressValidator.IsMailboxAddress(destination)
                     ? LNURL.LNURL.ExtractUriFromInternetIdentifier(destination)
                     : LNURL.LNURL.Parse(destination, out lnurlTag);
 

BTCPayServer/Extensions/ModelStateExtensions.cs

@@ -7,7 +7,6 @@ namespace BTCPayServer
 {
     public static class ModelStateExtensions
     {
-
         public static void AddModelError<TModel, TProperty>(this TModel source,
             Expression<Func<TModel, TProperty>> ex,
             string message,

BTCPayServer/Extensions/UserExtensions.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using BTCPayServer.Data;
 using BTCPayServer.Services.Invoices;
@@ -7,6 +8,15 @@ namespace BTCPayServer
 {
     public static class UserExtensions
     {
+        public static MimeKit.MailboxAddress GetMailboxAddress(this ApplicationUser user)
+        {
+            if (user is null)
+                throw new ArgumentNullException(nameof(user));
+            var name = user.UserName ?? String.Empty;
+            if (user.Email == user.UserName)
+                name = String.Empty;
+            return new MimeKit.MailboxAddress(name, user.Email);
+        }
         public static UserBlob GetBlob(this ApplicationUser user)
         {
             var result = user.Blob == null

BTCPayServer/HostedServices/BitpayIPNSender.cs

@@ -122,7 +122,7 @@ namespace BTCPayServer.HostedServices
 
             if (sendMail &&
                 invoice.NotificationEmail is String e &&
-                MailboxAddress.TryParse(e, out MailboxAddress notificationEmail))
+                MailboxAddressValidator.TryParse(e, out MailboxAddress notificationEmail))
             {
                 var json = NBitcoin.JsonConverters.Serializer.ToString(notification);
                 var store = await _StoreRepository.FindStore(invoice.StoreId);

BTCPayServer/HostedServices/StoreEmailRuleProcessorSender.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -53,20 +53,18 @@ public class StoreEmailRuleProcessorSender : EventHostedServiceBase
                     var sender = await _emailSenderFactory.GetEmailSender(invoiceEvent.Invoice.StoreId);
                     foreach (UIStoresController.StoreEmailRule actionableRule in actionableRules)
                     {
-                        var dest = actionableRule.To.Split(",", StringSplitOptions.RemoveEmptyEntries).Where(IsValidEmailAddress);
+                        var recipients = actionableRule.To.Split(",", StringSplitOptions.RemoveEmptyEntries)
-                        if (actionableRule.CustomerEmail && IsValidEmailAddress(invoiceEvent.Invoice.Metadata.BuyerEmail))
+                            .Select(o => { MailboxAddressValidator.TryParse(o, out var mb); return mb; })
+                            .Where(o => o != null)
+                            .ToList();
+                        if (actionableRule.CustomerEmail && MailboxAddressValidator.TryParse(invoiceEvent.Invoice.Metadata.BuyerEmail, out var bmb))
                         {
-                            dest = dest.Append(invoiceEvent.Invoice.Metadata.BuyerEmail);
+                            recipients.Add(bmb);
                         }
-
+                        sender.SendEmail(recipients.ToArray(), null, null, actionableRule.Subject, actionableRule.Body);
-                        var recipients = dest.Select(address => new MailboxAddress(address, address)).ToArray();
-                        sender.SendEmail(recipients, null, null, actionableRule.Subject, actionableRule.Body);
                     }
                 }
             }
         }
     }
-
-    private bool IsValidEmailAddress(string address) => 
-        !string.IsNullOrEmpty(address) && MailboxAddress.TryParse(address, out _);
 }

BTCPayServer/HostedServices/UserEventHostedService.cs

@@ -55,8 +55,7 @@ namespace BTCPayServer.HostedServices
                             new HostString(userRegisteredEvent.RequestUri.Host, userRegisteredEvent.RequestUri.Port),
                             userRegisteredEvent.RequestUri.PathAndQuery);
                         userRegisteredEvent.CallbackUrlGenerated?.SetResult(new Uri(callbackUrl));
-                        address = new MailboxAddress(userRegisteredEvent.User.Email,
+                        address = userRegisteredEvent.User.GetMailboxAddress();
-                            userRegisteredEvent.User.Email);
                         (await _emailSenderFactory.GetEmailSender()).SendEmailConfirmation(address, callbackUrl);
                     }
                     else if (!await _userManager.HasPasswordAsync(userRegisteredEvent.User))
@@ -86,8 +85,7 @@ passwordSetter:
                             userPasswordResetRequestedEvent.RequestUri.Port),
                         userPasswordResetRequestedEvent.RequestUri.PathAndQuery);
                     userPasswordResetRequestedEvent.CallbackUrlGenerated?.SetResult(new Uri(callbackUrl));
-                    address = new MailboxAddress(userPasswordResetRequestedEvent.User.Email,
+                    address = userPasswordResetRequestedEvent.User.GetMailboxAddress();
-                        userPasswordResetRequestedEvent.User.Email);
                     (await _emailSenderFactory.GetEmailSender())
                         .SendSetPasswordConfirmation(address, callbackUrl, newPassword);
                     break;

BTCPayServer/Models/InvoicingModels/CreateInvoiceModel.cs

@@ -50,7 +50,7 @@ namespace BTCPayServer.Models.InvoicingModels
             get; set;
         }
 
-        [EmailAddress]
+        [MailboxAddress]
         [DisplayName("Buyer Email")]
         public string BuyerEmail
         {
@@ -76,7 +76,7 @@ namespace BTCPayServer.Models.InvoicingModels
             get; set;
         }
 
-        [EmailAddress]
+        [MailboxAddress]
         [DisplayName("Notification Email")]
         public string NotificationEmail
         {

BTCPayServer/Models/InvoicingModels/UpdateCustomerModel.cs

@@ -1,10 +1,11 @@
 using System.ComponentModel.DataAnnotations;
+using BTCPayServer.Validation;
 
 namespace BTCPayServer.Models.InvoicingModels
 {
     public class UpdateCustomerModel
     {
-        [EmailAddress]
+        [MailboxAddress]
         [Required]
         public string Email
         {

BTCPayServer/Models/PaymentRequestViewModels/ListPaymentRequestsViewModel.cs

@@ -5,6 +5,7 @@ using BTCPayServer.Client.Models;
 using BTCPayServer.Data;
 using BTCPayServer.Services.Invoices;
 using BTCPayServer.Services.Rates;
+using BTCPayServer.Validation;
 using Microsoft.AspNetCore.Mvc.Rendering;
 using PaymentRequestData = BTCPayServer.Data.PaymentRequestData;
 
@@ -64,7 +65,7 @@ namespace BTCPayServer.Models.PaymentRequestViewModels
         [Display(Name = "Store")]
         public SelectList Stores { get; set; }
 
-        [EmailAddress]
+        [MailboxAddress]
         public string Email { get; set; }
 
         [MaxLength(500)]

BTCPayServer/Models/ServerViewModels/EmailsViewModel.cs

@@ -1,5 +1,6 @@
 using System.ComponentModel.DataAnnotations;
 using BTCPayServer.Services.Mails;
+using BTCPayServer.Validation;
 
 namespace BTCPayServer.Models.ServerViewModels
 {
@@ -19,7 +20,7 @@ namespace BTCPayServer.Models.ServerViewModels
             get; set;
         }
         public bool PasswordSet { get; set; }
-        [EmailAddress]
+        [MailboxAddressAttribute]
         [Display(Name = "Test Email")]
         public string TestEmail
         {

BTCPayServer/Plugins/PayButton/Models/PayButtonViewModel.cs

@@ -3,6 +3,7 @@ using System.ComponentModel.DataAnnotations;
 using BTCPayServer.ModelBinders;
 using BTCPayServer.Models.AppViewModels;
 using BTCPayServer.Models.StoreViewModels;
+using BTCPayServer.Validation;
 using Microsoft.AspNetCore.Mvc;
 
 namespace BTCPayServer.Plugins.PayButton.Models
@@ -34,7 +35,7 @@ namespace BTCPayServer.Plugins.PayButton.Models
         public string ServerIpn { get; set; }
         [Url]
         public string BrowserRedirect { get; set; }
-        [EmailAddress]
+        [MailboxAddress]
         public string NotifyEmail { get; set; }
 
         public string StoreId { get; set; }

BTCPayServer/Services/Mails/EmailSettings.cs

@@ -1,7 +1,10 @@
+using System.ComponentModel.DataAnnotations;
 using System.Threading;
 using System.Threading.Tasks;
 using BTCPayServer.Client.Models;
+using BTCPayServer.Validation;
 using MailKit.Net.Smtp;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
 using MimeKit;
 
 namespace BTCPayServer.Services.Mails
@@ -10,7 +13,29 @@ namespace BTCPayServer.Services.Mails
     {
         public bool IsComplete()
         {
-            return !string.IsNullOrWhiteSpace(Server) && Port is int;
+            return MailboxAddressValidator.IsMailboxAddress(From)
+                && !string.IsNullOrWhiteSpace(Server)
+                && Port is int;
+        }
+
+        public void Validate(string prefixKey, ModelStateDictionary modelState)
+        {
+            if (string.IsNullOrWhiteSpace(From))
+            {
+                modelState.AddModelError($"{prefixKey}{nameof(From)}", new RequiredAttribute().FormatErrorMessage(nameof(From)));
+            }
+            if (!MailboxAddressValidator.IsMailboxAddress(From))
+            {
+                modelState.AddModelError($"{prefixKey}{nameof(From)}", MailboxAddressAttribute.ErrorMessageConst);
+            }
+            if (string.IsNullOrWhiteSpace(Server))
+            {
+                modelState.AddModelError($"{prefixKey}{nameof(Server)}", new RequiredAttribute().FormatErrorMessage(nameof(Server)));
+            }
+            if (Port is null)
+            {
+                modelState.AddModelError($"{prefixKey}{nameof(Port)}", new RequiredAttribute().FormatErrorMessage(nameof(Port)));
+            }
         }
 
         public MimeMessage CreateMailMessage(MailboxAddress to, string subject, string message, bool isHtml) =>
@@ -30,12 +55,11 @@ namespace BTCPayServer.Services.Mails
             var mm = new MimeMessage();
             mm.Body = bodyBuilder.ToMessageBody();
             mm.Subject = subject;
-            mm.From.Add(new MailboxAddress(From, !string.IsNullOrWhiteSpace(FromDisplay) ? From : FromDisplay));
+            mm.From.Add(MailboxAddressValidator.Parse(From));
             mm.To.AddRange(to);
             mm.Cc.AddRange(cc ?? System.Array.Empty<InternetAddress>());
             mm.Bcc.AddRange(bcc ?? System.Array.Empty<InternetAddress>());
             return mm;
-            
         }
 
         public async Task<SmtpClient> CreateSmtpClient()

BTCPayServer/Validation/EmailValidator.cs

@@ -1,18 +0,0 @@
-using System;
-using System.Text.RegularExpressions;
-
-namespace BTCPayServer.Validation
-{
-    public class EmailValidator
-    {
-        static Regex _Email;
-        public static bool IsEmail(string str)
-        {
-            if (String.IsNullOrWhiteSpace(str))
-                return false;
-            if (_Email == null)
-                _Email = new Regex("^((([a-z]|\\d|[!#\\$%&'\\*\\+\\-\\/=\\?\\^_`{\\|}~]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])+(\\.([a-z]|\\d|[!#\\$%&'\\*\\+\\-\\/=\\?\\^_`{\\|}~]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])+)*)|((\\x22)((((\\x20|\\x09)*(\\x0d\\x0a))?(\\x20|\\x09)+)?(([\\x01-\\x08\\x0b\\x0c\\x0e-\\x1f\\x7f]|\\x21|[\\x23-\\x5b]|[\\x5d-\\x7e]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])|(\\\\([\\x01-\\x09\\x0b\\x0c\\x0d-\\x7f]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF]))))*(((\\x20|\\x09)*(\\x0d\\x0a))?(\\x20|\\x09)+)?(\\x22)))@((([a-z]|\\d|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])|(([a-z]|\\d|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])([a-z]|\\d|-|\\.|_|~|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])*([a-z]|\\d|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])))\\.)+(([a-z]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])|(([a-z]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])([a-z]|\\d|-|\\.|_|~|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])*([a-z]|[\\u00A0-\\uD7FF\\uF900-\\uFDCF\\uFDF0-\\uFFEF])))\\.?$", RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture | RegexOptions.Compiled, TimeSpan.FromSeconds(2.0));
-            return _Email.IsMatch(str);
-        }
-    }
-}

BTCPayServer/Validation/MailboxAddressAttribute.cs

@@ -0,0 +1,25 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace BTCPayServer.Validation
+{
+    /// <summary>
+    /// Validate address in the format "Firstname Lastname <blah@example.com>" See rfc822
+    /// </summary>
+    public class MailboxAddressAttribute : ValidationAttribute
+    {
+        public MailboxAddressAttribute()
+        {
+            ErrorMessage = ErrorMessageConst;
+        }
+        public const string ErrorMessageConst = "Invalid mailbox address. Some valid examples are: 'test@example.com' or 'Firstname Lastname <test@example.com>'";
+        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
+        {
+            if (value is null)
+                return ValidationResult.Success;
+            var str = value as string;
+            if (MailboxAddressValidator.IsMailboxAddress(str))
+                return ValidationResult.Success;
+            return new ValidationResult(ErrorMessage);
+        }
+    }
+}

BTCPayServer/Validation/MailboxAddressValidator.cs

@@ -0,0 +1,39 @@
+#nullable enable
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.Diagnostics.CodeAnalysis;
+using System.Text.RegularExpressions;
+using MimeKit;
+
+namespace BTCPayServer
+{
+    /// <summary>
+    /// Validate address in the format "Firstname Lastname <blah@example.com>" See rfc822
+    /// </summary>
+    public class MailboxAddressValidator
+    {
+        static ParserOptions _options;
+        static MailboxAddressValidator()
+        {
+            _options = ParserOptions.Default.Clone();
+            _options.AllowAddressesWithoutDomain = false;
+        }
+        public static bool IsMailboxAddress(string? str)
+        {
+            return TryParse(str, out _);
+        }
+        public static MailboxAddress Parse(string? str)
+        {
+            if (!TryParse(str, out var mb))
+                throw new FormatException("Invalid mailbox address (rfc822)");
+            return mb;
+        }
+        public static bool TryParse(string? str, [MaybeNullWhen(false)] out MailboxAddress mailboxAddress)
+        {
+            mailboxAddress = null;
+            if (String.IsNullOrWhiteSpace(str))
+                return false;
+            return MailboxAddress.TryParse(_options, str, out mailboxAddress) && mailboxAddress is not null;
+        }
+    }
+}

BTCPayServer/Views/Shared/EmailsBody.cshtml

@@ -39,17 +39,9 @@
                 <input asp-for="Settings.Port" data-fill="port" class="form-control"/>
                 <span asp-validation-for="Settings.Port" class="text-danger"></span>
             </div>
-            <div class="form-group">
-                <label asp-for="Settings.FromDisplay" class="form-label">Sender's display name</label>
-                <input asp-for="Settings.FromDisplay" class="form-control"/>
-                <small class="form-text text-muted">
-                    Some email providers (like Gmail) don't allow you to set your display name, so this setting may not have any effect.
-                </small>
-                <span asp-validation-for="Settings.FromDisplay" class="text-danger"></span>
-            </div>
             <div class="form-group">
                 <label asp-for="Settings.From" class="form-label">Sender's Email Address</label>
-                <input asp-for="Settings.From" class="form-control"/>
+                <input asp-for="Settings.From" class="form-control" placeholder="Firstname Lastname <email@example.com>" />
                 <span asp-validation-for="Settings.From" class="text-danger"></span>
             </div>
             <div class="form-group">
@@ -89,7 +81,7 @@
                     To test your settings, enter an email address below.
                 </p>
                 <label asp-for="TestEmail" class="form-label"></label>
-                <input asp-for="TestEmail" class="form-control" />
+                <input asp-for="TestEmail" placeholder="Firstname Lastname <email@example.com>" class="form-control" />
                 <span asp-validation-for="TestEmail" class="text-danger"></span>
             </div>
             <button type="submit" class="btn btn-secondary mt-2" name="command" value="Test" id="Test">Send Test Email</button>

BTCPayServer/Views/UIPaymentRequest/EditPaymentRequest.cshtml

@@ -73,7 +73,7 @@
             </div>
             <div class="form-group">
                 <label asp-for="Email" class="form-label"></label>
-                <input type="email" asp-for="Email" class="form-control" />
+                <input type="email" asp-for="Email" placeholder="Firstname Lastname <email@example.com>" class="form-control" />
                 <span asp-validation-for="Email" class="text-danger"></span>
                 <p id="PaymentRequestEmailHelpBlock" class="form-text text-muted">
                     Receive updates for this payment request.