Add LNURL-over-Nostr support (naddr + nprofile)

LNURL.Core/HttpLNURLCommunicator.cs

@@ -0,0 +1,31 @@
+using System;
+using System.Net.Http;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LNURL;
+
+/// <summary>
+/// An <see cref="ILNURLCommunicator"/> that performs LNURL requests over HTTP(S)
+/// using an <see cref="HttpClient"/>.
+/// </summary>
+public class HttpLNURLCommunicator : ILNURLCommunicator
+{
+    private readonly HttpClient _httpClient;
+
+    /// <summary>
+    /// Initializes a new instance with the specified <see cref="HttpClient"/>.
+    /// </summary>
+    /// <param name="httpClient">The HTTP client to use for requests. If <c>null</c>, a new instance is created.</param>
+    public HttpLNURLCommunicator(HttpClient httpClient = null)
+    {
+        _httpClient = httpClient ?? new HttpClient();
+    }
+
+    /// <inheritdoc />
+    public async Task<string> SendRequest(Uri lnurl, CancellationToken cancellationToken = default)
+    {
+        var response = await _httpClient.GetAsync(lnurl, cancellationToken);
+        return await response.Content.ReadAsStringAsync(cancellationToken);
+    }
+}

LNURL.Core/ILNURLCommunicator.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LNURL;
+
+/// <summary>
+/// Abstracts the transport layer for LNURL protocol communication,
+/// enabling LNURL flows over HTTP, Nostr, or other transports.
+/// </summary>
+public interface ILNURLCommunicator
+{
+    /// <summary>
+    /// Sends a request to the given LNURL endpoint and returns the raw JSON response.
+    /// </summary>
+    /// <param name="lnurl">The endpoint URI (may be an HTTP URL, <c>nostr:</c> URI, etc.).</param>
+    /// <param name="cancellationToken">A token to cancel the asynchronous operation.</param>
+    /// <returns>The raw JSON response string from the endpoint.</returns>
+    Task<string> SendRequest(Uri lnurl, CancellationToken cancellationToken = default);
+}

LNURL.Core/LNAuthRequest.cs

@@ -65,15 +65,22 @@ public enum LNAuthRequestAction
     /// <summary>
     /// Sends the signed challenge and public key to the LNURL-auth service to complete authentication.
     /// </summary>
-    public async Task<LNUrlStatusResponse> SendChallenge(ECDSASignature sig, PubKey key, HttpClient httpClient, CancellationToken cancellationToken = default)
+    public Task<LNUrlStatusResponse> SendChallenge(ECDSASignature sig, PubKey key, HttpClient httpClient, CancellationToken cancellationToken = default)
+    {
+        return SendChallenge(sig, key, new HttpLNURLCommunicator(httpClient), cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends the signed challenge using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// </summary>
+    public async Task<LNUrlStatusResponse> SendChallenge(ECDSASignature sig, PubKey key, ILNURLCommunicator communicator, CancellationToken cancellationToken = default)
     {
         var url = LNUrl;
         var uriBuilder = new UriBuilder(url);
         LNURL.AppendPayloadToQuery(uriBuilder, "sig", Encoders.Hex.EncodeData(sig.ToDER()));
         LNURL.AppendPayloadToQuery(uriBuilder, "key", key.ToHex());
         url = new Uri(uriBuilder.ToString());
-        var response = await httpClient.GetAsync(url, cancellationToken);
-        var content = await response.Content.ReadAsStringAsync(cancellationToken);
+        var content = await communicator.SendRequest(url, cancellationToken);
 
         return System.Text.Json.JsonSerializer.Deserialize<LNUrlStatusResponse>(content, LNURLJsonOptions.Default);
     }
@@ -87,6 +94,15 @@ public Task<LNUrlStatusResponse> SendChallenge(Key key, HttpClient httpClient, C
         return SendChallenge(sig, key.PubKey, httpClient, cancellationToken);
     }
 
+    /// <summary>
+    /// Signs the <see cref="K1"/> challenge with the given key and sends the result using a custom transport.
+    /// </summary>
+    public Task<LNUrlStatusResponse> SendChallenge(Key key, ILNURLCommunicator communicator, CancellationToken cancellationToken = default)
+    {
+        var sig = SignChallenge(key);
+        return SendChallenge(sig, key.PubKey, communicator, cancellationToken);
+    }
+
     /// <summary>
     /// Signs this request's <see cref="K1"/> challenge with the given private key.
     /// </summary>

LNURL.Core/LNURL.cs

@@ -72,7 +72,8 @@ public static Uri Parse(string lnurl, out string tag)
             Bech32Engine.Decode(lnurl, out _, out var data);
             var result = new Uri(Encoding.UTF8.GetString(data));
 
-            if (!result.IsOnion() && !result.Scheme.Equals("https") && !result.IsLocalNetwork())
+            if (!result.IsOnion() && !result.Scheme.Equals("https") && !result.IsLocalNetwork() &&
+                result.Scheme != "nostr")
                 throw new FormatException("LNURL provided is not secure.");
 
             var query = result.ParseQueryString();
@@ -83,7 +84,9 @@ public static Uri Parse(string lnurl, out string tag)
         if (Uri.TryCreate(lnurl, UriKind.Absolute, out var lud17Uri) &&
             SchemeTagMapping.TryGetValue(lud17Uri.Scheme.ToLowerInvariant(), out tag))
             return new Uri(lud17Uri.ToString()
-                .Replace(lud17Uri.Scheme + ":", lud17Uri.IsOnion() ? "http:" : "https:"));
+                .Replace(lud17Uri.Scheme + ":",
+                    (lud17Uri.Host.StartsWith("nprofile1") || lud17Uri.Host.StartsWith("naddr1")) ? "nostr:" :
+                    lud17Uri.IsOnion() ? "http:" : "https:"));
 
         throw new FormatException("LNURL uses bech32 and 'lnurl' as the hrp (LUD1) or an lnurl LUD17 scheme. ");
     }
@@ -98,8 +101,10 @@ public static Uri Parse(string lnurl, out string tag)
     /// </exception>
     public static string EncodeBech32(Uri serviceUrl)
     {
-        if (serviceUrl.Scheme != "https" && !serviceUrl.IsOnion() && !serviceUrl.IsLocalNetwork())
-            throw new ArgumentException("serviceUrl must be an onion service OR https based OR on the local network",
+        if (serviceUrl.Scheme != "https" && !serviceUrl.IsOnion() && !serviceUrl.IsLocalNetwork() &&
+            serviceUrl.Scheme != "nostr")
+            throw new ArgumentException(
+                "serviceUrl must be an onion service OR https based OR on the local network OR a Nostr NIP-21 URI",
                 nameof(serviceUrl));
 
         return Bech32Engine.Encode("lnurl", Encoding.UTF8.GetBytes(serviceUrl.ToString()));
@@ -114,8 +119,10 @@ public static string EncodeBech32(Uri serviceUrl)
     /// <returns>A <see cref="Uri"/> in the chosen encoding format.</returns>
     public static Uri EncodeUri(Uri serviceUrl, string tag, bool bech32)
     {
-        if (serviceUrl.Scheme != "https" && !serviceUrl.IsOnion() && !serviceUrl.IsLocalNetwork())
-            throw new ArgumentException("serviceUrl must be an onion service OR https based OR on the local network",
+        if (serviceUrl.Scheme != "https" && !serviceUrl.IsOnion() && !serviceUrl.IsLocalNetwork() &&
+            serviceUrl.Scheme != "nostr")
+            throw new ArgumentException(
+                "serviceUrl must be an onion service OR https based OR on the local network OR a Nostr NIP-21 URI",
                 nameof(serviceUrl));
         if (string.IsNullOrEmpty(tag)) tag = serviceUrl.ParseQueryString().Get("tag");
         if (tag == "login") LNAuthRequest.EnsureValidUrl(serviceUrl);
@@ -221,6 +228,21 @@ public static Task<object> FetchInformation(Uri lnUrl, string tag, HttpClient ht
     /// Supports fast withdraw (LUD-03 query-string parameters) and LNURL-auth (LUD-04) inline parsing.
     /// </summary>
     public static async Task<object> FetchInformation(Uri lnUrl, string tag, HttpClient httpClient, CancellationToken cancellationToken)
+    {
+        return await FetchInformation(lnUrl, tag, new HttpLNURLCommunicator(httpClient), cancellationToken);
+    }
+
+    /// <summary>
+    /// Fetches LNURL endpoint information using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// This enables LNURL flows over Nostr or other non-HTTP transports.
+    /// </summary>
+    public static Task<object> FetchInformation(Uri lnUrl, string tag, ILNURLCommunicator communicator)
+    {
+        return FetchInformation(lnUrl, tag, communicator, default);
+    }
+
+    /// <inheritdoc cref="FetchInformation(Uri, string, ILNURLCommunicator)"/>
+    public static async Task<object> FetchInformation(Uri lnUrl, string tag, ILNURLCommunicator communicator, CancellationToken cancellationToken)
     {
         try
         {
@@ -231,22 +253,20 @@ public static async Task<object> FetchInformation(Uri lnUrl, string tag, HttpCli
             // ignored
         }
 
-        if (tag is null) tag = lnUrl.ParseQueryString().Get("tag");
+        tag ??= lnUrl.ParseQueryString().Get("tag");
         NameValueCollection queryString;
-        HttpResponseMessage response;
         string k1;
         switch (tag)
         {
             case null:
-                response = await httpClient.GetAsync(lnUrl, cancellationToken);
-                var content = await response.Content.ReadAsStringAsync(cancellationToken);
+                var content = await communicator.SendRequest(lnUrl, cancellationToken);
 
                 using (var doc = JsonDocument.Parse(content))
                 {
                     if (doc.RootElement.TryGetProperty("tag", out var tagToken))
                     {
                         tag = tagToken.GetString();
-                        return DeserializeByTag(content, tag);
+                        return DeserializeByTag(content, tag, lnUrl);
                     }
                 }
 
@@ -257,12 +277,11 @@ public static async Task<object> FetchInformation(Uri lnUrl, string tag, HttpCli
                 var minWithdrawable = queryString.Get("minWithdrawable");
                 var maxWithdrawable = queryString.Get("maxWithdrawable");
                 var defaultDescription = queryString.Get("defaultDescription");
-                var callback = queryString.Get("callback");
-                if (k1 is null || minWithdrawable is null || maxWithdrawable is null || callback is null)
+                var callback = queryString.Get("callback") ?? lnUrl.ToString();
+                if (k1 is null || minWithdrawable is null || maxWithdrawable is null)
                 {
-                    response = await httpClient.GetAsync(lnUrl, cancellationToken);
-                    var withdrawContent = await response.Content.ReadAsStringAsync(cancellationToken);
-                    return DeserializeByTag(withdrawContent, tag);
+                    var withdrawContent = await communicator.SendRequest(lnUrl, cancellationToken);
+                    return DeserializeByTag(withdrawContent, tag, lnUrl);
                 }
 
                 return new LNURLWithdrawRequest
@@ -290,23 +309,33 @@ public static async Task<object> FetchInformation(Uri lnUrl, string tag, HttpCli
                 };
 
             default:
-                response = await httpClient.GetAsync(lnUrl, cancellationToken);
-                var defaultContent = await response.Content.ReadAsStringAsync(cancellationToken);
-                return DeserializeByTag(defaultContent, tag);
+                var defaultContent = await communicator.SendRequest(lnUrl, cancellationToken);
+                return DeserializeByTag(defaultContent, tag, lnUrl);
         }
     }
 
-    private static object DeserializeByTag(string json, string tag)
+    private static object DeserializeByTag(string json, string tag, Uri lnUrl = null)
     {
         if (LNUrlStatusResponse.IsErrorResponse(json, out var errorResponse)) return errorResponse;
 
-        return tag switch
+        switch (tag)
         {
-            "channelRequest" => JsonSerializer.Deserialize<LNURLChannelRequest>(json, LNURLJsonOptions.Default),
-            "hostedChannelRequest" => JsonSerializer.Deserialize<LNURLHostedChannelRequest>(json, LNURLJsonOptions.Default),
-            "withdrawRequest" => JsonSerializer.Deserialize<LNURLWithdrawRequest>(json, LNURLJsonOptions.Default),
-            "payRequest" => JsonSerializer.Deserialize<LNURLPayRequest>(json, LNURLJsonOptions.Default),
-            _ => JsonDocument.Parse(json)
-        };
+            case "channelRequest":
+                var channelRequest = JsonSerializer.Deserialize<LNURLChannelRequest>(json, LNURLJsonOptions.Default);
+                channelRequest.Callback ??= lnUrl;
+                return channelRequest;
+            case "hostedChannelRequest":
+                return JsonSerializer.Deserialize<LNURLHostedChannelRequest>(json, LNURLJsonOptions.Default);
+            case "withdrawRequest":
+                var withdrawRequest = JsonSerializer.Deserialize<LNURLWithdrawRequest>(json, LNURLJsonOptions.Default);
+                withdrawRequest.Callback ??= lnUrl;
+                return withdrawRequest;
+            case "payRequest":
+                var payRequest = JsonSerializer.Deserialize<LNURLPayRequest>(json, LNURLJsonOptions.Default);
+                payRequest.Callback ??= lnUrl;
+                return payRequest;
+            default:
+                return JsonDocument.Parse(json);
+        }
     }
 }

LNURL.Core/LNURLChannelRequest.cs

@@ -49,7 +49,16 @@ public class LNURLChannelRequest
     /// <summary>
     /// Sends a channel open request to the service callback.
     /// </summary>
-    public async Task SendRequest(PubKey ourId, bool privateChannel, HttpClient httpClient,
+    public Task SendRequest(PubKey ourId, bool privateChannel, HttpClient httpClient,
+        CancellationToken cancellationToken = default)
+    {
+        return SendRequest(ourId, privateChannel, new HttpLNURLCommunicator(httpClient), cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends a channel open request using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// </summary>
+    public async Task SendRequest(PubKey ourId, bool privateChannel, ILNURLCommunicator communicator,
         CancellationToken cancellationToken = default)
     {
         var url = Callback;
@@ -59,15 +68,22 @@ public async Task SendRequest(PubKey ourId, bool privateChannel, HttpClient http
         LNURL.AppendPayloadToQuery(uriBuilder, "private", privateChannel ? "1" : "0");
 
         url = new Uri(uriBuilder.ToString());
-        var response = await httpClient.GetAsync(url, cancellationToken);
-        var content = await response.Content.ReadAsStringAsync(cancellationToken);
+        var content = await communicator.SendRequest(url, cancellationToken);
         if (LNUrlStatusResponse.IsErrorResponse(content, out var error)) throw new LNUrlException(error.Reason);
     }
 
     /// <summary>
     /// Sends a cancellation request for this channel request to the service callback.
     /// </summary>
-    public async Task CancelRequest(PubKey ourId, HttpClient httpClient, CancellationToken cancellationToken = default)
+    public Task CancelRequest(PubKey ourId, HttpClient httpClient, CancellationToken cancellationToken = default)
+    {
+        return CancelRequest(ourId, new HttpLNURLCommunicator(httpClient), cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends a cancellation request using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// </summary>
+    public async Task CancelRequest(PubKey ourId, ILNURLCommunicator communicator, CancellationToken cancellationToken = default)
     {
         var url = Callback;
         var uriBuilder = new UriBuilder(url);
@@ -76,8 +92,7 @@ public async Task CancelRequest(PubKey ourId, HttpClient httpClient, Cancellatio
         LNURL.AppendPayloadToQuery(uriBuilder, "cancel", "1");
 
         url = new Uri(uriBuilder.ToString());
-        var response = await httpClient.GetAsync(url, cancellationToken);
-        var content = await response.Content.ReadAsStringAsync(cancellationToken);
+        var content = await communicator.SendRequest(url, cancellationToken);
         if (LNUrlStatusResponse.IsErrorResponse(content, out var error)) throw new LNUrlException(error.Reason);
     }
 }

LNURL.Core/LNURLPayRequest.cs

@@ -31,7 +31,7 @@
     /// <summary>
     /// Gets or sets the callback URL to which the wallet sends the payment amount to receive a BOLT11 invoice.
     /// </summary>
-    [JsonProperty("callback")]
+    [JsonProperty("callback", NullValueHandling = NullValueHandling.Ignore)]
     [JsonConverter(typeof(UriJsonConverter))]
     [STJ.JsonPropertyName("callback")]
     public Uri Callback { get; set; }
@@ -105,7 +105,7 @@
     /// </summary>
     [JsonProperty("nostrPubkey", NullValueHandling = NullValueHandling.Ignore)]
     [STJ.JsonPropertyName("nostrPubkey")]
     public string? NostrPubkey { get; set; }
 
     /// <summary>
     /// Gets or sets whether this service supports Nostr zap receipts (NIP-57).
@@ -148,8 +148,20 @@
     /// Sends the second step of the LNURL-pay flow (LUD-06) by calling the service callback with the
     /// chosen amount, optional comment (LUD-12), and optional payer data (LUD-18).
     /// </summary>
+    public Task<LNURLPayRequestCallbackResponse> SendRequest(LightMoney amount, Network network,
+        HttpClient httpClient, string comment = null, LUD18PayerDataResponse payerData = null,
+        CancellationToken cancellationToken = default)
+    {
+        return SendRequest(amount, network, new HttpLNURLCommunicator(httpClient), comment, payerData,
+            cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends the second step of the LNURL-pay flow (LUD-06) using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// </summary>
     public async Task<LNURLPayRequestCallbackResponse> SendRequest(LightMoney amount, Network network,
-        HttpClient httpClient, string comment = null, LUD18PayerDataResponse payerData = null, CancellationToken cancellationToken = default)
+        ILNURLCommunicator communicator, string comment = null, LUD18PayerDataResponse payerData = null,
+        CancellationToken cancellationToken = default)
     {
         var url = Callback;
         var uriBuilder = new UriBuilder(url);
@@ -161,8 +173,7 @@
                 HttpUtility.UrlEncode(System.Text.Json.JsonSerializer.Serialize(payerData, LNURLJsonOptions.Default)));
 
         url = new Uri(uriBuilder.ToString());
-        var response = await httpClient.GetAsync(url, cancellationToken);
-        var content = await response.Content.ReadAsStringAsync(cancellationToken);
+        var content = await communicator.SendRequest(url, cancellationToken);
         if (LNUrlStatusResponse.IsErrorResponse(content, out var error)) throw new LNUrlException(error.Reason);
 
         var result = System.Text.Json.JsonSerializer.Deserialize<LNURLPayRequestCallbackResponse>(content, LNURLJsonOptions.Default);
@@ -192,19 +203,19 @@
     {
         [JsonProperty("name", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("name")]
         public PayerDataField Name { get; set; }
 
         [JsonProperty("pubkey", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("pubkey")]
         public PayerDataField Pubkey { get; set; }
 
         [JsonProperty("email", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("email")]
         public PayerDataField Email { get; set; }
 
         [JsonProperty("auth", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("auth")]
         public AuthPayerDataField Auth { get; set; }
     }
 
     /// <summary>
@@ -214,16 +225,16 @@
     {
         [JsonProperty("name", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("name")]
         public string Name { get; set; }
 
         [JsonProperty("pubkey", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [JsonConverter(typeof(PubKeyJsonConverter))]
         [STJ.JsonPropertyName("pubkey")]
         public PubKey Pubkey { get; set; }
 
         [JsonProperty("email", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("email")]
         public string Email { get; set; }
 
         [JsonProperty("auth", DefaultValueHandling = DefaultValueHandling.Ignore)]
         [STJ.JsonPropertyName("auth")]

LNURL.Core/LNURLWithdrawRequest.cs

@@ -107,7 +107,16 @@ public Task<LNUrlStatusResponse> SendRequest(string bolt11, HttpClient httpClien
     /// Sends a withdrawal request to the service callback with the specified BOLT11 invoice,
     /// optional PIN, and optional balance notification URL.
     /// </summary>
-    public async Task<LNUrlStatusResponse> SendRequest(string bolt11, HttpClient httpClient, string pin = null,
+    public Task<LNUrlStatusResponse> SendRequest(string bolt11, HttpClient httpClient, string pin = null,
+        Uri balanceNotify = null, CancellationToken cancellationToken = default)
+    {
+        return SendRequest(bolt11, new HttpLNURLCommunicator(httpClient), pin, balanceNotify, cancellationToken);
+    }
+
+    /// <summary>
+    /// Sends a withdrawal request using a custom <see cref="ILNURLCommunicator"/> transport.
+    /// </summary>
+    public async Task<LNUrlStatusResponse> SendRequest(string bolt11, ILNURLCommunicator communicator, string pin = null,
         Uri balanceNotify = null, CancellationToken cancellationToken = default)
     {
         var url = Callback;
@@ -118,8 +127,7 @@ public async Task<LNUrlStatusResponse> SendRequest(string bolt11, HttpClient htt
         if (pin != null) LNURL.AppendPayloadToQuery(uriBuilder, "pin", pin);
 
         url = new Uri(uriBuilder.ToString());
-        var response = await httpClient.GetAsync(url, cancellationToken);
-        var content = await response.Content.ReadAsStringAsync(cancellationToken);
+        var content = await communicator.SendRequest(url, cancellationToken);
 
         return System.Text.Json.JsonSerializer.Deserialize<LNUrlStatusResponse>(content, LNURLJsonOptions.Default);
     }