Merge pull request #22 from remcoros/fix/idpreimage_serialization

address serialization issues in 'ToIdPreimage' and 'BaseNostrEventTagJsonConverter'

Author: Kukks

NNostr.Client/JsonConverters/BaseNostrEventTagJsonConverter.cs

@@ -21,11 +21,11 @@ namespace NNostr.Client.JsonConverters;
         {
             if (i == 0)
             {
-                result.TagIdentifier = StringEscaperJsonConverter.JavaScriptStringEncode(reader.GetString(), false);
+                result.TagIdentifier = reader.GetString();
             }
             else
             {
-                result.Data.Add(StringEscaperJsonConverter.JavaScriptStringEncode(reader.GetString(), false));
+                result.Data.Add(reader.GetString());
             }
 
             reader.Read();

NNostr.Client/NNostr.Client.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
-        <TargetFrameworks>net6.0;net7.0;net8.0</TargetFrameworks>
+        <TargetFrameworks>net6.0;net7.0;net8.0;netstandard2.1</TargetFrameworks>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
         <LangVersion>11</LangVersion>
@@ -15,8 +15,6 @@
         <license>MIT</license>
         <RepositoryUrl>https://github.com/Kukks/NNostr</RepositoryUrl>
         <PackageTags>Nostr</PackageTags>
-        <TargetFrameworks>net6.0;net7.0;netstandard2.1</TargetFrameworks>    
-
     </PropertyGroup>
 
     <ItemGroup>

NNostr.Client/NostrEventTag.cs

@@ -1,5 +1,3 @@
-using System.Text.Encodings.Web;
-using System.Text.Json;
 using System.Text.Json.Serialization;
 using NNostr.Client.JsonConverters;
 
@@ -8,16 +6,9 @@ namespace NNostr.Client
     [JsonConverter(typeof(NostrEventTagJsonConverter))]
     public class NostrEventTag
     {
-        private static readonly JsonSerializerOptions _unsafeJsonEscapingOptions = new() { Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping };
         public string TagIdentifier { get; set; }
         public List<string> Data { get; set; } = new();
 
-        public override string ToString()
-        {
-            var d = TagIdentifier is null ? Data : Data.Prepend(TagIdentifier);
-            return JsonSerializer.Serialize(d, _unsafeJsonEscapingOptions);
-        }
-        
         public bool Equals(NostrEventTag? x, NostrEventTag? y)
         {
             if (ReferenceEquals(x, y)) return true;

NNostr.Client/NostrExtensions.cs

@@ -1,23 +1,24 @@
 using System.Net.WebSockets;
 using System.Runtime.CompilerServices;
-using System.Security.Cryptography;
 using System.Threading.Channels;
-using LinqKit;
 using NBitcoin.Secp256k1;
 using NNostr.Client.JsonConverters;
-using SHA256 = System.Security.Cryptography.SHA256;
 
 namespace NNostr.Client
 {
     public static class NostrExtensions
     {
-        
         public static string ToIdPreimage<TNostrEvent, TEventTag>(this TNostrEvent nostrEvent, bool withoutId)
             where TNostrEvent : BaseNostrEvent<TEventTag> where TEventTag : NostrEventTag
         {
-            var content = StringEscaperJsonConverter.JavaScriptStringEncode(nostrEvent.Content, false);
+            var content = StringEscaperJsonConverter.JavaScriptStringEncode(nostrEvent.Content ?? string.Empty, false);
+            var tagContent = string.Join(',', nostrEvent.Tags.Select(tag =>
+            {
+                var data = tag.TagIdentifier is null ? tag.Data : tag.Data.Prepend(tag.TagIdentifier);
+                return $"[{string.Join(",", data.Select(d => $"\"{StringEscaperJsonConverter.JavaScriptStringEncode(d, false)}\""))}]";
+            }));
             return
-                $"[{(withoutId ? 0 : $"\"{nostrEvent.Id}\"")},\"{nostrEvent.PublicKey}\",{nostrEvent.CreatedAt?.ToUnixTimeSeconds()},{nostrEvent.Kind},[{string.Join(',', nostrEvent.Tags.Select(tag => tag))}],\"{content}\"]";
+                $"[{(withoutId ? 0 : $"\"{nostrEvent.Id}\"")},\"{nostrEvent.PublicKey}\",{nostrEvent.CreatedAt?.ToUnixTimeSeconds() ?? 0},{nostrEvent.Kind},[{tagContent}],\"{content}\"]";
         }
 
         public static string ComputeEventId(this string eventJson)

NNostr.Tests/NIP57Tests.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Text.Json;
+using System.Threading.Tasks;
+using NNostr.Client;
+using Xunit;
+using Xunit.Abstractions;
+
+namespace NNostr.Tests;
+
+public class NIP57Tests
+{
+    private readonly ITestOutputHelper _output;
+
+    public NIP57Tests(ITestOutputHelper output)
+    {
+        _output = output;
+    }
+
+    [Fact]
+    public async Task ValidateZapReceipt()
+    {
+        var privKeyStr = "0514ce6aae1eb9897d32ccce0cc40c6942a1f2f04f5554618dd97f430c9e386f";
+        var privKey = NostrExtensions.ParseKey(privKeyStr);
+        var pubKey = privKey.CreateXOnlyPubKey();
+        var pubKeyHex = pubKey.ToHex();
+
+        var evtRequestStr =
+            """{"id":"cd8bb08cb5a74d67d49d73f8838057385fb8c584427629d81b54e29a1c7708bb","pubkey":"8cacc4de163d6547e740ac4338a3c4569ce4028f0299fae841a00028d68c04e3","created_at":1717408922,"kind":9734,"content":"Great post 👍","tags":[["p","23378c18cb34edc0ea5f979b41703df2799fed769595e31312fef04b8011c0d6"],["amount","21000"],["relays","wss://nostr.mom"],["e","e6dceff3a4cd834edd17c170a41146086e6a200c5f012232bc80840856ddfa27"]],"sig":"a950026e445b27c818013f97a120d1c3c21f94a0e0362379c76cad1a95131ec14071f9b4339afaca2e17144138058db77f415202b92ce52763966fdda97c219d"}""";
+        var evtReceipt = new NostrEvent()
+        {
+            Kind = 9735,
+            Content = "Great post 👍",
+            CreatedAt = DateTimeOffset.FromUnixTimeSeconds(1717408928),
+            PublicKey = pubKeyHex,
+            Tags = {
+                new(){ TagIdentifier = "p", Data = { "23378c18cb34edc0ea5f979b41703df2799fed769595e31312fef04b8011c0d6" }},
+                new(){ TagIdentifier = "e", Data = { "e6dceff3a4cd834edd17c170a41146086e6a200c5f012232bc80840856ddfa27" }},
+                new(){ TagIdentifier = "description", Data = { evtRequestStr }},
+            }
+        };
+        evtReceipt = await evtReceipt.ComputeIdAndSignAsync(privKey);
+        
+        var evtReceiptStr = JsonSerializer.Serialize(evtReceipt);
+
+        _output.WriteLine("Receipt:");
+        _output.WriteLine(evtReceiptStr);
+        
+        // Since we both sign and verify from the same 'ToIdPreimage', this will always succeed, even if the computation of the id is invalid
+        // Use a tool like https://nak.nostr.com/ to copy/paste the event receipt string and verify if the signature is valid
+        Assert.True(evtReceipt.Verify());
+    }
+}