Make NFC built in (#4541)

* Make NFC built int

* support checkout v2

* uninstall old plugin

* fix lnurl in unified checkout

* fix tests

* fix tests

* fix old checkout unified qr

* clean up and make nfc submission more sturdy

* support topup invoices for lnurlw

* fix test

* Payment URI fixes

* Fix LNURL exclusion cases

* UI updates

* Adapt test

---------

Co-authored-by: Dennis Reimann <mail@dennisreimann.de>

BTCPayServer.Tests/Checkoutv2Tests.cs

@@ -61,14 +61,14 @@ namespace BTCPayServer.Tests
             Assert.Contains("LNURL", s.Driver.FindElement(By.CssSelector(".payment-method:nth-child(2)")).Text);
             var payUrl = s.Driver.FindElement(By.CssSelector(".btn-primary")).GetAttribute("href");
             Assert.StartsWith("bitcoin:", payUrl);
-            Assert.DoesNotContain("&lightning=", payUrl);
+            Assert.DoesNotContain("lightning=", payUrl);
             
             // Switch to LNURL
             s.Driver.FindElement(By.CssSelector(".payment-method:nth-child(2)")).Click();
             TestUtils.Eventually(() =>
             {
                 payUrl = s.Driver.FindElement(By.CssSelector(".btn-primary")).GetAttribute("href");
-                Assert.StartsWith("lightning:", payUrl);
+                Assert.StartsWith("lightning:lnurl", payUrl);
             });
 
             // Default payment method
@@ -78,9 +78,9 @@ namespace BTCPayServer.Tests
 
             Assert.Equal(2, s.Driver.FindElements(By.CssSelector(".payment-method")).Count);
             Assert.Contains("Lightning", s.Driver.WaitForElement(By.CssSelector(".payment-method.active")).Text);
-            Assert.DoesNotContain("LNURL", s.Driver.PageSource);
+            Assert.Contains("Bitcoin", s.Driver.WaitForElement(By.CssSelector(".payment-method")).Text);
             payUrl = s.Driver.FindElement(By.CssSelector(".btn-primary")).GetAttribute("href");
-            Assert.StartsWith("lightning:", payUrl);
+            Assert.StartsWith("lightning:lnbcrt", payUrl);
 
             // Lightning amount in Sats
             Assert.Contains("BTC", s.Driver.FindElement(By.Id("AmountDue")).Text);
@@ -188,17 +188,16 @@ namespace BTCPayServer.Tests
             Assert.Empty(s.Driver.FindElements(By.CssSelector(".payment-method")));
             payUrl = s.Driver.FindElement(By.CssSelector(".btn-primary")).GetAttribute("href");
             Assert.StartsWith("bitcoin:", payUrl);
-            Assert.Contains("&lightning=", payUrl);
+            Assert.Contains("&lightning=lnbcrt", payUrl);
 
             // BIP21 with topup invoice
             s.GoToHome();
             invoiceId = s.CreateInvoice(amount: null);
             s.GoToInvoiceCheckout(invoiceId);
-            Assert.Equal(2, s.Driver.FindElements(By.CssSelector(".payment-method")).Count);
-            Assert.Contains("Bitcoin", s.Driver.FindElement(By.CssSelector(".payment-method.active")).Text);
-            Assert.Contains("LNURL", s.Driver.FindElement(By.CssSelector(".payment-method:nth-child(2)")).Text);
+            Assert.Empty(s.Driver.FindElements(By.CssSelector(".payment-method")));
             payUrl = s.Driver.FindElement(By.CssSelector(".btn-primary")).GetAttribute("href");
-            Assert.DoesNotContain("&lightning=", payUrl);
+            Assert.StartsWith("bitcoin:", payUrl);
+            Assert.DoesNotContain("&lightning=lnurl", payUrl);
 
             // Expiry message should not show amount for topup invoice
             expirySeconds = s.Driver.FindElement(By.Id("ExpirySeconds"));

BTCPayServer/Controllers/UIInvoiceController.UI.cs

@@ -649,12 +649,13 @@ namespace BTCPayServer.Controllers
             var storeBlob = store.GetStoreBlob();
             var btcId = PaymentMethodId.Parse("BTC");
             var lnId = PaymentMethodId.Parse("BTC_LightningLike");
+            var lnurlId = PaymentMethodId.Parse("BTC_LNURLPAY");
             if (paymentMethodId is null)
             {
                 var enabledPaymentIds = store.GetEnabledPaymentIds(_NetworkProvider)
-                    // Exclude LNURL for Checkout v2 + non-top up invoices
-                    .Where(pmId => storeBlob.CheckoutType == CheckoutType.V1 || 
-                                   pmId.PaymentType is not LNURLPayPaymentType || invoice.IsUnsetTopUp())
+                    .Where(pmId => storeBlob.CheckoutType == CheckoutType.V1 ||
+                        // Exclude LNURL for Checkout v2 + non-top up invoices
+                        (pmId.PaymentType is not LNURLPayPaymentType || invoice.IsUnsetTopUp()))
                     .ToArray();
 
                 // Exclude Lightning if OnChainWithLnInvoiceFallback is active and we have both payment methods
@@ -802,11 +803,9 @@ namespace BTCPayServer.Controllers
                 IsMultiCurrency = invoice.GetPayments(false).Select(p => p.GetPaymentMethodId()).Concat(new[] { paymentMethod.GetId() }).Distinct().Count() > 1,
                 StoreId = store.Id,
                 AvailableCryptos = invoice.GetPaymentMethods()
-                                          .Where(i => i.Network != null &&
+                                          .Where(i => i.Network != null && storeBlob.CheckoutType == CheckoutType.V1 ||
                                               // Exclude LNURL for Checkout v2 + non-top up invoices
-                                              (storeBlob.CheckoutType == CheckoutType.V1 ||
-                                               i.GetId().PaymentType is not LNURLPayPaymentType ||
-                                               invoice.IsUnsetTopUp()))
+                                              i.GetId().PaymentType is not LNURLPayPaymentType || invoice.IsUnsetTopUp())
                                           .Select(kv =>
                                           {
                                               var availableCryptoPaymentMethodId = kv.GetId();
@@ -836,10 +835,15 @@ namespace BTCPayServer.Controllers
             {
                 var onchainPM = model.AvailableCryptos.Find(c => c.PaymentMethodId == btcId.ToString());
                 var lightningPM = model.AvailableCryptos.Find(c => c.PaymentMethodId == lnId.ToString());
+                var lnurlPM = model.AvailableCryptos.Find(c => c.PaymentMethodId == lnurlId.ToString());
                 if (onchainPM != null && lightningPM != null)
                 {
                     model.AvailableCryptos.Remove(lightningPM);
                 }
+                if (onchainPM != null && lnurlPM != null)
+                {
+                    model.AvailableCryptos.Remove(lnurlPM);
+                }
             }
 
             paymentMethodHandler.PreparePaymentModel(model, dto, storeBlob, paymentMethod);

BTCPayServer/Controllers/UIStoresController.cs

@@ -504,11 +504,8 @@ namespace BTCPayServer.Controllers
             }
 
             blob.CheckoutType = model.UseNewCheckout ? Client.Models.CheckoutType.V2 : Client.Models.CheckoutType.V1;
-            if (blob.CheckoutType == Client.Models.CheckoutType.V2)
-            {
-                blob.OnChainWithLnInvoiceFallback = model.OnChainWithLnInvoiceFallback;
-            }
 
+            blob.OnChainWithLnInvoiceFallback = model.OnChainWithLnInvoiceFallback;
             blob.RequiresRefundEmail = model.RequiresRefundEmail;
             blob.LazyPaymentMethods = model.LazyPaymentMethods;
             blob.RedirectAutomatically = model.RedirectAutomatically;

BTCPayServer/Payments/Bitcoin/BitcoinLikePaymentHandler.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using BTCPayServer.Client.Models;
-using BTCPayServer.Common;
 using BTCPayServer.Data;
 using BTCPayServer.HostedServices;
 using BTCPayServer.Logging;
@@ -11,6 +10,7 @@ using BTCPayServer.Models;
 using BTCPayServer.Models.InvoicingModels;
 using BTCPayServer.Services;
 using BTCPayServer.Services.Invoices;
+using Microsoft.AspNetCore.Http;
 using NBitcoin;
 using NBitcoin.DataEncoders;
 using NBXplorer.Models;
@@ -69,13 +69,24 @@ namespace BTCPayServer.Payments.Bitcoin
             {
                 var lightningInfo = invoiceResponse.CryptoInfo.FirstOrDefault(a =>
                     a.GetpaymentMethodId() == new PaymentMethodId(model.CryptoCode, PaymentTypes.LightningLike));
-
-
-                // Turn the colon into an equal sign to trun the whole into the lightning part of the query string
-
-                // lightningInfo?.PaymentUrls?.BOLT11:  lightning:lnbcrt440070n1p3ua9np...
-                lightningFallback = lightningInfo?.PaymentUrls?.BOLT11.Replace("lightning:", "lightning=", StringComparison.OrdinalIgnoreCase);
-                // lightningFallback: lightning=lnbcrt440070n1p3ua9np...
+                if (lightningInfo is not null && !string.IsNullOrEmpty(lightningInfo.PaymentUrls?.BOLT11))
+                {
+                    lightningFallback = lightningInfo.PaymentUrls.BOLT11;
+                }   
+                else
+                {
+                    var lnurl = invoiceResponse.CryptoInfo.FirstOrDefault(a =>
+                        a.GetpaymentMethodId() == new PaymentMethodId(model.CryptoCode, PaymentTypes.LNURLPay));
+                    if (lnurl is not null)
+                    {
+                        lightningFallback = LNURL.LNURL.EncodeUri(new Uri(lnurl.Url), "payRequest", true).ToString();
+                    }
+                }
+                if (!string.IsNullOrEmpty(lightningFallback))
+                {
+                    lightningFallback = lightningFallback
+                        .Replace("lightning:", "lightning=", StringComparison.OrdinalIgnoreCase);
+                }
             }
 
             if (model.Activated)

BTCPayServer/Plugins/NFC/NFCController.cs

@@ -0,0 +1,183 @@
+using System;
+using System.Net.Http;
+using System.Threading.Tasks;
+using BTCPayServer.Client.Models;
+using BTCPayServer.Data.Payouts.LightningLike;
+using BTCPayServer.Payments;
+using BTCPayServer.Payments.Lightning;
+using BTCPayServer.Services;
+using BTCPayServer.Services.Invoices;
+using BTCPayServer.Services.Stores;
+using LNURL;
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using NBitcoin;
+
+namespace BTCPayServer.Plugins.NFC
+{
+    [Route("plugins/NFC")]
+    public class NFCController : Controller
+    {
+        private readonly IHttpClientFactory _httpClientFactory;
+        private readonly InvoiceRepository _invoiceRepository;
+        private readonly UILNURLController _uilnurlController;
+        private readonly InvoiceActivator _invoiceActivator;
+        private readonly StoreRepository _storeRepository;
+
+        public NFCController(IHttpClientFactory httpClientFactory,
+            InvoiceRepository invoiceRepository,
+            UILNURLController uilnurlController,
+            InvoiceActivator invoiceActivator,
+            StoreRepository storeRepository)
+        {
+            _httpClientFactory = httpClientFactory;
+            _invoiceRepository = invoiceRepository;
+            _uilnurlController = uilnurlController;
+            _invoiceActivator = invoiceActivator;
+            _storeRepository = storeRepository;
+        }
+
+        public class SubmitRequest
+        {
+            public string Lnurl { get; set; }
+            public string InvoiceId { get; set; }
+            public long? Amount { get; set; }
+        }
+
+        [AllowAnonymous]
+        public async Task<IActionResult> SubmitLNURLWithdrawForInvoice([FromBody] SubmitRequest request)
+        {
+            var invoice = await _invoiceRepository.GetInvoice(request.InvoiceId);
+            if (invoice?.Status is not InvoiceStatusLegacy.New)
+            {
+                return NotFound();
+            }
+
+            var methods = invoice.GetPaymentMethods();
+            PaymentMethod lnPaymentMethod = null;
+            if (!methods.TryGetValue(new PaymentMethodId("BTC", PaymentTypes.LNURLPay), out var lnurlPaymentMethod) &&
+                !methods.TryGetValue(new PaymentMethodId("BTC", PaymentTypes.LightningLike), out lnPaymentMethod))
+            {
+                return BadRequest("destination for lnurlw was not specified");
+            }
+
+            Uri uri;
+            string tag;
+            try
+            {
+                uri = LNURL.LNURL.Parse(request.Lnurl, out tag);
+                if (uri is null)
+                {
+                    return BadRequest("lnurl was malformed");
+                }
+            }
+            catch (Exception e)
+            {
+                return BadRequest(e.Message);
+            }
+
+
+            if (!string.IsNullOrEmpty(tag) && !tag.Equals("withdrawRequest"))
+            {
+                return BadRequest("lnurl was not lnurl-withdraw");
+            }
+
+            var httpClient = _httpClientFactory.CreateClient(uri.IsOnion()
+                ? LightningLikePayoutHandler.LightningLikePayoutHandlerOnionNamedClient
+                : LightningLikePayoutHandler.LightningLikePayoutHandlerClearnetNamedClient);
+            var info = (await
+                LNURL.LNURL.FetchInformation(uri, "withdrawRequest", httpClient)) as LNURLWithdrawRequest;
+            if (info?.Callback is null)
+            {
+                return BadRequest("Could not fetch info from lnurl-withdraw ");
+            }
+
+            httpClient = _httpClientFactory.CreateClient(info.Callback.IsOnion()
+                ? LightningLikePayoutHandler.LightningLikePayoutHandlerOnionNamedClient
+                : LightningLikePayoutHandler.LightningLikePayoutHandlerClearnetNamedClient);
+
+            string bolt11 = null;
+
+            if (lnPaymentMethod is not null)
+            {
+                if (lnPaymentMethod.GetPaymentMethodDetails() is LightningLikePaymentMethodDetails
+                    {
+                        Activated: false
+                    } lnPMD)
+                {
+                    var store = await _storeRepository.FindStore(invoice.StoreId);
+                    await _invoiceActivator.ActivateInvoicePaymentMethod(lnPaymentMethod.GetId(), invoice, store);
+                }
+
+                lnPMD = lnPaymentMethod.GetPaymentMethodDetails() as LightningLikePaymentMethodDetails;
+                Money due;
+                if (invoice.Type == InvoiceType.TopUp && request.Amount is not null)
+                {
+                    due = new Money(request.Amount.Value, MoneyUnit.Satoshi);
+                }else if (invoice.Type == InvoiceType.TopUp)
+                {
+                    return BadRequest("This is a topup invoice and you need to provide the amount in sats to pay.");
+                }
+                else
+                {
+                    due =  lnPaymentMethod.Calculate().Due;
+                }
+                if (info.MinWithdrawable > due || due > info.MaxWithdrawable)
+                {
+                    return BadRequest("invoice amount is not payable with the lnurl allowed amounts.");
+                }
+
+                if (lnPMD?.Activated is true)
+                {
+                    bolt11 = lnPMD.BOLT11;
+                }
+            }
+
+            if (lnurlPaymentMethod is not null)
+            {
+                Money due;
+                if (invoice.Type == InvoiceType.TopUp && request.Amount is not null)
+                {
+                    due = new Money(request.Amount.Value, MoneyUnit.Satoshi);
+                }else if (invoice.Type == InvoiceType.TopUp)
+                {
+                    return BadRequest("This is a topup invoice and you need to provide the amount in sats to pay.");
+                }
+                else
+                {
+                    due =  lnurlPaymentMethod.Calculate().Due;
+                }
+
+                var response = await _uilnurlController.GetLNURLForInvoice(request.InvoiceId, "BTC",
+                    due.Satoshi);
+
+                if (response is ObjectResult objectResult)
+                {
+                    switch (objectResult.Value)
+                    {
+                        case LNURLPayRequest.LNURLPayRequestCallbackResponse lnurlPayRequestCallbackResponse:
+                            bolt11 = lnurlPayRequestCallbackResponse.Pr;
+                            break;
+                        case LNUrlStatusResponse lnUrlStatusResponse:
+
+                            return BadRequest(
+                                $"Could not fetch bolt11 invoice to pay to: {lnUrlStatusResponse.Reason}");
+                    }
+                }
+            }
+
+            if (bolt11 is null)
+            {
+                return BadRequest("Could not fetch bolt11 invoice to pay to.");
+            }
+
+            var result = await info.SendRequest(bolt11, httpClient);
+            if (result.Status.Equals("ok", StringComparison.InvariantCultureIgnoreCase))
+            {
+                return Ok(result.Reason);
+            }
+
+            return BadRequest(result.Reason);
+        }
+    }
+}

BTCPayServer/Plugins/NFC/NFCPlugin.cs

@@ -0,0 +1,31 @@
+using BTCPayServer.Abstractions.Contracts;
+using BTCPayServer.Abstractions.Models;
+using BTCPayServer.Abstractions.Services;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace BTCPayServer.Plugins.NFC
+{
+    public class NFCPlugin : BaseBTCPayServerPlugin
+    {
+        
+        public override string Identifier => "BTCPayServer.Plugins.NFC";
+        public override string Name => "NFC";
+        public override string Description => "Allows you to support contactless card payments over NFC and LNURL Withdraw!";
+
+        
+        public override void Execute(IServiceCollection applicationBuilder)
+        {
+            applicationBuilder.AddSingleton<IUIExtension>(new UIExtension("NFC/CheckoutEnd",
+                "checkout-end"));
+            applicationBuilder.AddSingleton<IUIExtension>(new UIExtension("NFC/LNURLNFCPostContent",
+                "checkout-lightning-post-content"));            
+            applicationBuilder.AddSingleton<IUIExtension>(new UIExtension("NFC/CheckoutEnd",
+                "checkout-v2-end"));
+            applicationBuilder.AddSingleton<IUIExtension>(new UIExtension("NFC/LNURLNFCPostContent",
+                "checkout-v2-lightning-post-content"));
+            applicationBuilder.AddSingleton<IUIExtension>(new UIExtension("NFC/LNURLNFCPostContent",
+                "checkout-v2-bitcoin-post-content"));
+            base.Execute(applicationBuilder);
+        }
+    }
+}

BTCPayServer/Plugins/PluginManager.cs

@@ -120,6 +120,12 @@ namespace BTCPayServer.Plugins
 
             foreach (var toLoad in pluginsToLoad)
             {
+                // This used to be a standalone plugin but due to popular demand has been made as part of core. If we detect an install, we remove the redundant plugin.
+                if (toLoad.PluginIdentifier == "BTCPayServer.Plugins.NFC")
+                {
+                    QueueCommands(pluginsFolder, ("delete", toLoad.PluginIdentifier));
+                    continue;
+                }
                 if (!loadedPluginIdentifiers.Add(toLoad.PluginIdentifier))
                     continue;
                 try

BTCPayServer/Views/Shared/Bitcoin/BitcoinLikeMethodCheckout-v2.cshtml

@@ -2,6 +2,7 @@
 @model BTCPayServer.Models.InvoicingModels.PaymentModel
 
 <template id="bitcoin-method-checkout-template">
+    @await Component.InvokeAsync("UiExtensionPoint", new {location = "checkout-v2-bitcoin-pre-content", model = Model})
     <div class="payment-box">
         <div v-if="model.invoiceBitcoinUrlQR" class="qr-container" :data-clipboard="model.btcAddress" data-clipboard-confirm-element="QR_Text_@Model.PaymentMethodId">
             <div>
@@ -17,15 +18,16 @@
             </div>
             <button type="button" class="btn btn-link" data-clipboard-target="#Address_@Model.PaymentMethodId" :data-clipboard-confirm="$t('copy_confirm')" v-t="'copy'"></button>
         </div>
-        <div v-if="BOLT11" class="input-group mt-3">
+        <div v-if="lightning" class="input-group mt-3">
             <div class="form-floating">
-                <input id="BOLT11_@Model.PaymentMethodId" class="form-control-plaintext" readonly="readonly" :value="BOLT11" />
-                <label for="BOLT11_@Model.PaymentMethodId" v-t="'lightning'"></label>
+                <input id="Lightning_@Model.PaymentMethodId" class="form-control-plaintext" readonly="readonly" :value="lightning" />
+                <label for="Lightning_@Model.PaymentMethodId" v-t="'lightning'"></label>
             </div>
-            <button type="button" class="btn btn-link" data-clipboard-target="#BOLT11_@Model.PaymentMethodId" :data-clipboard-confirm="$t('copy_confirm')" v-t="'copy'"></button>
+            <button type="button" class="btn btn-link" data-clipboard-target="#Lightning_@Model.PaymentMethodId" :data-clipboard-confirm="$t('copy_confirm')" v-t="'copy'"></button>
         </div>
         <a v-if="model.invoiceBitcoinUrl" class="btn btn-primary rounded-pill w-100 mt-4" target="_top"
            :href="model.invoiceBitcoinUrl" :title="$t(hasPayjoin ? 'BIP21 payment link with PayJoin support' : 'BIP21 payment link')" v-t="'pay_in_wallet'"></a>
+        @await Component.InvokeAsync("UiExtensionPoint", new {location = "checkout-v2-bitcoin-post-content", model = Model})
     </div>
 </template>
 
@@ -44,8 +46,8 @@
             hasPayjoin () {
                 return this.model.invoiceBitcoinUrl.indexOf('@PayjoinClient.BIP21EndpointKey=') !== -1;
             },
-            BOLT11 () {
-                const match = this.model.invoiceBitcoinUrl.match(/&lightning=(.*)&?/i);
+            lightning () {
+                const match = this.model.invoiceBitcoinUrl.match(/[&?]lightning=(.*)&?/i);
                 return match ? match[1].toLowerCase() : null;
             }
         }

BTCPayServer/Views/Shared/Lightning/LightningLikeMethodCheckout-v2.cshtml

@@ -2,6 +2,7 @@
 
 <template id="lightning-method-checkout-template">
     <div class="payment-box">
+        @await Component.InvokeAsync("UiExtensionPoint" ,  new { location="checkout-v2-lightning-pre-content", model = Model})
         <div v-if="model.invoiceBitcoinUrlQR" class="qr-container" :data-clipboard="model.btcAddress" data-clipboard-confirm-element="QR_Text_@Model.PaymentMethodId">
             <div>
                 <qrcode :value="model.invoiceBitcoinUrlQR" tag="div" :options="qrOptions" />
@@ -18,6 +19,7 @@
         </div>
         <a v-if="model.invoiceBitcoinUrl" class="btn btn-primary rounded-pill w-100 mt-4" target="_top"
            :href="model.invoiceBitcoinUrl" v-t="'pay_in_wallet'"></a>
+        @await Component.InvokeAsync("UiExtensionPoint", new {location = "checkout-v2-lightning-post-content", model = Model})
     </div>          
 </template>
 

BTCPayServer/Views/Shared/NFC/CheckoutEnd.cshtml

@@ -0,0 +1,133 @@
+@using BTCPayServer.Abstractions.Extensions
+@using Microsoft.AspNetCore.Mvc.TagHelpers
+@using BTCPayServer.Abstractions.TagHelpers
+<template id="lnurl-withdraw-template">
+    <button v-if="v2" class="btn btn-secondary rounded-pill w-100 mt-4" type="button" 
+            v-on:click="startScan" 
+            v-bind:disabled="scanning || submitting" 
+            v-bind:class="{ 'loading': scanning || submitting, 'text-secondary': !supported }">{{btnText}}</button>
+
+    <bp-loading-button v-else>
+        <button v-on:click="startScan"  style="margin-top: 15px;" v-bind:disabled="scanning || submitting"
+                v-bind:class="{ 'loading': scanning || submitting, 'action-button': supported, 'btn btn-text w-100': !supported  }">
+            <span class="button-text">{{btnText}}</span>
+            <div class="loader-wrapper">
+                <partial name="Checkout-Spinner" />
+            </div>
+        </button>
+    </bp-loading-button>
+</template>
+<script type="text/javascript">
+Vue.component("lnurl-withdraw-checkout", {
+    template: "#lnurl-withdraw-template",
+    computed: {
+        v2: function() {
+          return !!this.$parent.model;
+        },
+        topup: function (){
+           return (this.$parent.srvModel || this.$parent.model).isUnsetTopUp;
+        },
+        destination: function (){
+            return (this.$parent.srvModel || this.$parent.model).invoiceId;
+        },
+        btnText: function (){
+            return this.supported? "Pay by NFC & LNURL-Withdraw" : "Pay by LNURL-Withdraw";
+        }
+    },
+    data: function () {
+        return {
+            url : @Safe.Json(Context.Request.GetAbsoluteUri(Url.Action("SubmitLNURLWithdrawForInvoice", "NFC"))),
+            supported: ('NDEFReader' in window && window.self === window.top),
+            scanning: false,
+            submitting: false,
+            readerAbortController: null,
+            amount: 0
+        }
+    },
+    methods: {
+        startScan: async function () {
+            try {
+                if (this.scanning || this.submitting) {
+                    return;
+                }
+                if (this.topup) {
+                    const amountStr = prompt("How many sats do you want to pay?")
+                    if (amountStr){
+                        try {
+                            this.amount = parseInt(amountStr)
+                        } catch {
+                            alert("Please provide a valid number amount in sats");
+                        }
+                    }else{
+                        return;    
+                    }
+                }
+                
+                const self = this;
+                self.submitting = false;
+                self.scanning = true;
+                if (!this.supported) {
+                    const result = prompt("Enter LNURL withdraw");
+                    if (result) {
+                        self.sendData.bind(self)(result);
+                        return;
+                    }
+                    self.scanning = false;
+                }
+                ndef = new NDEFReader()
+                self.readerAbortController = new AbortController()
+                await ndef.scan({signal: self.readerAbortController.signal})
+
+                ndef.addEventListener('readingerror', () => {
+                    self.scanning = false;
+                    self.readerAbortController.abort()
+                })
+
+                ndef.addEventListener('reading', ({message, serialNumber}) => {
+                    //Decode NDEF data from tag
+                    const record = message.records[0]
+                    const textDecoder = new TextDecoder('utf-8')
+                    const lnurl = textDecoder.decode(record.data)
+
+                    //User feedback, show loader icon
+                    self.scanning = false;
+                    self.sendData.bind(self)(lnurl);
+
+                })
+            } catch(e) {
+                self.scanning = false;
+                self.submitting = false;
+            }
+        },
+        sendData: function (lnurl) {
+
+            this.submitting = true;
+            //Post LNURLW data to server
+            var xhr = new XMLHttpRequest()
+            xhr.open('POST', this.url, true)
+            xhr.setRequestHeader('Content-Type', 'application/json')
+            xhr.send(JSON.stringify({lnurl, invoiceId: this.destination, amount: this.amount}))
+            const self = this;
+            //User feedback, reset on failure
+            xhr.onload = function () {
+                if (xhr.readyState === xhr.DONE) {
+                    console.log(xhr.response);
+                    console.log(xhr.responseText);
+                    self.scanning = false;
+                    self.submitting = false;
+
+                    if(self.readerAbortController) {
+                        self.readerAbortController.abort()
+                    }
+
+                    if(xhr.response){
+                        alert(xhr.response)
+                    }
+                }
+            }
+        }
+    }
+});
+
+
+</script>

BTCPayServer/Views/Shared/NFC/LNURLNFCPostContent.cshtml

@@ -0,0 +1,3 @@
+<lnurl-withdraw-checkout>
+
+</lnurl-withdraw-checkout>

BTCPayServer/Views/UIInvoice/CheckoutV2.cshtml

@@ -47,7 +47,7 @@
                 <h5 class="text-center mt-1 mb-3 fw-semibold" v-if="srvModel.itemDesc" v-text="srvModel.itemDesc">@Model.ItemDesc</h5>
                 @if (Model.IsUnsetTopUp)
                 {
-                    <h2 id="AmountDue" class="text-center mb-3" v-t="'any_amount'"></h2>
+                    <h2 id="AmountDue" class="text-center" v-t="'any_amount'"></h2>
                 }
                 else
                 {
@@ -237,5 +237,6 @@
         <partial name="@paymentMethodHandler.ExtensionPartial-v2" model="@Model"/>
     }
     @await Component.InvokeAsync("UiExtensionPoint", new { location = "checkout-payment", model = Model })
+    @await Component.InvokeAsync("UiExtensionPoint", new { location = "checkout-v2-end", model = Model })
 </body>
 </html>

BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml

@@ -10,7 +10,7 @@
 }
 
 @section PageFootContent {
-    <partial name="_ValidationScriptsPartial"/>
+    <partial name="_ValidationScriptsPartial" />
     <script>
         delegate('click', '.setTheme', e => {
             e.preventDefault();
@@ -60,7 +60,7 @@
                     </table>
                 </div>
             }
-            
+
             <h3 class="mt-5 mb-3">Checkout</h3>
             <div class="d-flex align-items-center mb-3">
                 <input asp-for="UseNewCheckout" type="checkbox" class="btcpay-toggle me-3" data-bs-toggle="collapse" data-bs-target=".checkout-settings" aria-expanded="@(Model.UseNewCheckout)" aria-controls="NewCheckoutSettings" />
@@ -71,30 +71,29 @@
                     </label>
                     <span asp-validation-for="UseNewCheckout" class="text-danger"></span>
                     <div class="form-text">
-                        Since v1.7.0 a new version of the checkout is available. Note: For now, the new version is English-only.<br/>
+                        Since v1.7.0 a new version of the checkout is available. Note: For now, the new version is English-only.<br />
                         We are still collecting <a href="https://github.com/btcpayserver/btcpayserver/discussions/4308" target="_blank" rel="noreferrer noopener">feedback</a> and offer this as an opt-in feature.
                     </div>
                 </div>
             </div>
-                            
+
             <div class="checkout-settings collapse @(Model.UseNewCheckout ? "show" : "")" id="NewCheckoutSettings">
-                <div class="form-check">
-                    <input asp-for="OnChainWithLnInvoiceFallback" type="checkbox" class="form-check-input"/>
-                    <label asp-for="OnChainWithLnInvoiceFallback" class="form-check-label"></label>
-                    <a href="https://bitcoinqr.dev/" target="_blank" rel="noreferrer noopener">
-                        <span class="fa fa-question-circle-o text-secondary" title="More information..."></span>
-                    </a>
-                </div>
                 <div class="form-group">
                     <label asp-for="DisplayExpirationTimer" class="form-label"></label>
                     <div class="input-group">
-                        <input inputmode="numeric" asp-for="DisplayExpirationTimer" class="form-control" style="max-width:10ch;"/>
+                        <input inputmode="numeric" asp-for="DisplayExpirationTimer" class="form-control" style="max-width:10ch;" />
                         <span class="input-group-text">minutes</span>
                     </div>
                     <span asp-validation-for="DisplayExpirationTimer" class="text-danger"></span>
                 </div>
             </div>
-                            
+            <div class="form-check">
+                <input asp-for="OnChainWithLnInvoiceFallback" type="checkbox" class="form-check-input" />
+                <label asp-for="OnChainWithLnInvoiceFallback" class="form-check-label"></label>
+                <a href="https://bitcoinqr.dev/" target="_blank" rel="noreferrer noopener">
+                    <span class="fa fa-question-circle-o text-secondary" title="More information..."></span>
+                </a>
+            </div>
             <div class="checkout-settings collapse @(Model.UseNewCheckout ? "" : "show")" id="OldCheckoutSettings">
                 <div class="form-check">
                     <input asp-for="RequiresRefundEmail" type="checkbox" class="form-check-input" />
@@ -102,7 +101,7 @@
                 </div>
                 <div class="form-group">
                     <div class="form-check">
-                        <input asp-for="AutoDetectLanguage" type="checkbox" class="form-check-input"/>
+                        <input asp-for="AutoDetectLanguage" type="checkbox" class="form-check-input" />
                         <label asp-for="AutoDetectLanguage" class="form-check-label"></label>
                         <div class="form-text">Detects the language of the customer's browser with 99.9% accuracy.</div>
                     </div>
@@ -132,7 +131,7 @@
                         <a href="#" class="setTheme" data-theme="dark">Dark</a> |
                         <a href="#" class="setTheme" data-theme="legacy">Legacy</a>
                     </div>
-                    @await Component.InvokeAsync("UiExtensionPoint", new { location = "invoice-checkout-theme-options", model = Model })
+                    @await Component.InvokeAsync("UiExtensionPoint", new {location = "invoice-checkout-theme-options", model = Model})
                 </div>
             </div>
 
@@ -141,7 +140,6 @@
                 <input asp-for="HtmlTitle" class="form-control" />
                 <span asp-validation-for="HtmlTitle" class="text-danger"></span>
             </div>
-            
             <div class="form-check my-3">
                 <input asp-for="LazyPaymentMethods" type="checkbox" class="form-check-input" />
                 <label asp-for="LazyPaymentMethods" class="form-check-label"></label>
@@ -150,7 +148,6 @@
                 <input asp-for="RedirectAutomatically" type="checkbox" class="form-check-input" />
                 <label asp-for="RedirectAutomatically" class="form-check-label"></label>
             </div>
-            
             <h3 class="mt-5 mb-3">Public receipt</h3>
             <div class="form-check my-3">
                 <input asp-for="ReceiptOptions.Enabled" type="checkbox" class="form-check-input" />
@@ -164,7 +161,6 @@
                 <input asp-for="ReceiptOptions.ShowQR" type="checkbox" class="form-check-input" />
                 <label asp-for="ReceiptOptions.ShowQR" class="form-check-label"></label>
             </div>
-            
             <button type="submit" class="btn btn-primary mt-4" id="Save">Save</button>
         </form>
     </div>