overhaul JSON implementation - now it works! (resolves #21)

ActivityPub.Client/ActivityPubClient.cs

@@ -1,10 +1,12 @@
 // This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
 // If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+using System.Net.Http.Headers;
 using System.Text.Json;
 using ActivityPub.Common.TypeInfo;
 using ActivityPub.Common.Util;
 using ActivityPub.Types;
+using ActivityPub.Types.Json;
 using ActivityPub.Types.Util;
 
 namespace ActivityPub.Client;
@@ -17,8 +19,9 @@ public class ActivityPubClient : IActivityPubClient
     private readonly HttpClient _httpClient = new();
     private readonly ITypeInfoCache _typeInfoCache;
     private readonly ActivityPubOptions _apOptions;
+    private readonly IJsonLdSerializer _jsonLdSerializer;
 
-    public ActivityPubClient(ITypeInfoCache typeInfoCache, ActivityPubOptions apOptions)
+    public ActivityPubClient(ITypeInfoCache typeInfoCache, ActivityPubOptions apOptions, IJsonLdSerializer jsonLdSerializer)
     {
         _typeInfoCache = typeInfoCache;
         _apOptions = apOptions;
@@ -50,7 +53,7 @@ private async Task<ASType> Get(Uri uri, Type targetType, int? maxRecursion, Canc
             throw new ApplicationException($"Request failed: unsupported content type {mediaType}");
 
         var json = await resp.Content.ReadAsStringAsync(cancellationToken);
-        var jsonObj = JsonSerializer.Deserialize(json, targetType, _apOptions.SerializerOptions);
+        var jsonObj = _jsonLdSerializer.Deserialize(json, targetType);
         if (jsonObj is not ASType obj)
             throw new JsonException($"Failed to deserialize object - parser returned unsupported object {jsonObj?.GetType()}");
 

ActivityPub.Client/ClientModule.cs

@@ -9,11 +9,9 @@ namespace ActivityPub.Client;
 
 public static class ClientModule
 {
-    public const string ConfigSection = "ClientModule";
-
     public static void TryAddClientModule(this HostApplicationBuilder builder)
     {
-        builder.TryAddCommonModule();
+        builder.Services.TryAddCommonModule();
         builder.Services.TryAddSingleton<IActivityPubClient, ActivityPubClient>();
     }
 }

ActivityPub.Common/ActivityPub.Common.csproj

@@ -7,12 +7,11 @@
     </PropertyGroup>
 
     <ItemGroup>
-        <ProjectReference Include="..\ActivityPub.Types\ActivityPub.Types.csproj"/>
+        <ProjectReference Include="..\ActivityPub.Types\ActivityPub.Types.csproj" />
     </ItemGroup>
 
     <ItemGroup>
-        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="7.0.0"/>
-        <PackageReference Include="Microsoft.Extensions.Hosting" Version="7.0.1"/>
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="7.0.0" />
     </ItemGroup>
 
     <ItemGroup>

ActivityPub.Common/CommonModule.cs

@@ -3,18 +3,19 @@
 
 using ActivityPub.Common.TypeInfo;
 using ActivityPub.Common.Util;
+using ActivityPub.Types;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
-using Microsoft.Extensions.Hosting;
 
 namespace ActivityPub.Common;
 
 public static class CommonModule
 {
-    public const string ConfigSection = "CommonModule";
-
-    public static void TryAddCommonModule(this HostApplicationBuilder builder)
+    public static void TryAddCommonModule(this IServiceCollection services)
     {
-        builder.Services.TryAddSingleton<ITypeInfoCache, TypeInfoCache>();
-        builder.Services.TryAddSingleton<ActivityPubOptions>();
+        services.TryAddTypesModule();
+
+        services.TryAddSingleton<ITypeInfoCache, TypeInfoCache>();
+        services.TryAddSingleton<ActivityPubOptions>();
     }
 }

ActivityPub.Common/TypeInfo/TypeInfo.cs

@@ -5,6 +5,9 @@
 
 namespace ActivityPub.Common.TypeInfo;
 
+// TODO move this entire module into the sample app.
+// Why did I put it here in the first place??
+
 public class TypeInfo
 {
     public required Type Type { get; init; }

ActivityPub.Types/ASLink.cs

@@ -1,10 +1,10 @@
 // This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
 // If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
 using System.Text.Json.Nodes;
 using System.Text.Json.Serialization;
-using ActivityPub.Types.Internal;
 using ActivityPub.Types.Json;
 using ActivityPub.Types.Util;
 
@@ -18,9 +18,8 @@ namespace ActivityPub.Types;
 /// Properties of the Link are properties of the reference as opposed to properties of the resource. 
 /// </summary>
 /// <seealso href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-link"/>
-[JsonConverter(typeof(ASLinkConverter))]
 [ASTypeKey(LinkType)]
-public class ASLink : ASType, IJsonConvertible<ASLink>
+public class ASLink : ASType
 {
     public const string LinkType = "Link";
 
@@ -79,77 +78,36 @@ protected ASLink(string type) : base(type) {}
     public static implicit operator ASUri(ASLink link) => link.HRef;
     public static implicit operator ASLink(ASUri asUri) => new() { HRef = asUri };
 
-
-    protected override void ReadJson(JsonElement element, JsonOptions options)
-    {
-        base.ReadJson(element, options);
-
-        // Skip HRef - it has to be pre-initialized
-        if (element.TryGetProperty("hreflang", out var hRefLang))
-            HRefLang = hRefLang.GetString();
-        if (element.TryGetProperty("width", out var width))
-            Width = width.GetInt32();
-        if (element.TryGetProperty("height", out var height))
-            Height = height.GetInt32();
-        if (element.TryGetProperty("rel", out var rel))
-            Rel = rel.Deserialize<HashSet<string>>(options.SerializerOptions)!;
-    }
-
-    protected override void WriteJson(JsonNode node, JsonOptions options)
-    {
-        base.WriteJson(node, options);
-
-        node["href"] = JsonValue.Create(HRef, options.NodeOptions);
-        if (HRefLang != null)
-            node["hreflang"] = JsonValue.Create(HRefLang, options.NodeOptions);
-        if (Width != null)
-            node["width"] = JsonValue.Create(Width, options.NodeOptions);
-        if (Height != null)
-            node["height"] = JsonValue.Create(Height, options.NodeOptions);
-        if (Rel.Count > 0)
-            node["rel"] = JsonSerializer.SerializeToNode(Rel, options.SerializerOptions);
-    }
-
-    public new static ASLink? Deserialize(JsonElement element, JsonOptions options)
+    [CustomJsonDeserializer]
+    public static bool TryDeserialize(JsonElement element, JsonSerializerOptions options, [NotNullWhen(true)] out ASLink? obj)
     {
-        if (element.ValueKind == JsonValueKind.Null)
-            return null;
-
-        // Parse flattened form
+        // We either parse from string, or allow parser to use default logic
         if (element.ValueKind == JsonValueKind.String)
         {
-            return new ASLink()
+            obj = new ASLink
             {
                 HRef = element.GetString()!
             };
+            return true;
         }
 
-        if (element.ValueKind == JsonValueKind.Object && element.TryGetProperty("href", out var href) && href.TryGetString(out var hrefString))
-        {
-            var link = new ASLink
-            {
-                HRef = hrefString
-            };
-            link.ReadJson(element, options);
-            return link;
-        }
 
-        throw new JsonException("Can't deserialize ASLink - not in any supported form");
+        obj = null;
+        return false;
     }
 
-    public static JsonNode? Serialize(ASLink obj, JsonOptions options)
+    [CustomJsonSerializer]
+    public static bool TrySerialize(ASLink obj, JsonSerializerOptions options, JsonNodeOptions nodeOptions, [NotNullWhen(true)] out JsonNode? node)
     {
-        // TODO split ASLink into flat and object form
-
         // If its only a link, then use the flattened form
         if (obj.HasOnlyHRef)
         {
-            return JsonValue.Create(obj.HRef.Uri.ToString(), options.NodeOptions);
+            node = JsonValue.Create(obj.HRef.Uri.ToString(), nodeOptions)!;
+            return true;
         }
 
-        var node = new JsonObject(options.NodeOptions);
-        obj.WriteJson(node, options);
-        return node;
+        node = null;
+        return false;
     }
 
     /// <summary>

ActivityPub.Types/ASType.cs

@@ -2,10 +2,7 @@
 // If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/.
 
 using System.Diagnostics.CodeAnalysis;
-using System.Text.Json;
-using System.Text.Json.Nodes;
 using System.Text.Json.Serialization;
-using ActivityPub.Types.Internal;
 using ActivityPub.Types.Json;
 using ActivityPub.Types.Util;
 
@@ -18,7 +15,7 @@ namespace ActivityPub.Types;
 /// This is a synthetic type created to help adapt ActivityStreams to the .NET object model.
 /// It does not exist in the ActivityStreams standard.
 /// </remarks>
-public abstract class ASType : IJsonConvertible<ASType>
+public abstract class ASType
 {
     protected ASType(string defaultType) => Types.Add(defaultType);
 
@@ -108,48 +105,4 @@ public string? Id
     /// <seealso href="https://www.w3.org/TR/activitystreams-vocabulary/#dfn-mediaType"/>
     [JsonPropertyName("mediaType")]
     public Linkable<ASObject>? MediaType { get; set; }
-
-
-    protected virtual void ReadJson(JsonElement element, JsonOptions options)
-    {
-        if (element.TryGetProperty("type", out var type))
-            Types = type.Deserialize<HashSet<string>>(options.SerializerOptions)!;
-
-        if (element.TryGetProperty("@context", out var ldContext))
-            JsonLdContexts = ldContext.Deserialize<HashSet<string>>(options.SerializerOptions)!;
-
-        if (element.TryGetProperty("id", out var id) && id.TryGetString(out var idStr))
-            Id = idStr;
-
-        if (element.TryGetProperty("attributedTo", out var attributedTo))
-            AttributedTo = attributedTo.Deserialize<LinkableList<ASObject>>(options.SerializerOptions)!;
-
-        if (element.TryGetProperty("preview", out var preview))
-            Preview = preview.Deserialize<Linkable<ASObject>>(options.SerializerOptions)!;
-
-        if (element.TryGetProperty("name", out var name))
-            Name = name.Deserialize<NaturalLanguageString>(options.SerializerOptions)!;
-
-        if (element.TryGetProperty("mediaType", out var mediaType))
-            MediaType = mediaType.Deserialize<Linkable<ASObject>>(options.SerializerOptions)!;
-    }
-
-    protected virtual void WriteJson(JsonNode node, JsonOptions options)
-    {
-        node["type"] = JsonSerializer.SerializeToNode(Types, options.SerializerOptions);
-        node["@context"] = JsonSerializer.SerializeToNode(JsonLdContexts, options.SerializerOptions);
-        if (!IsAnonymous)
-            node["id"] = JsonValue.Create(Id, options.NodeOptions);
-        if (AttributedTo.Count > 0)
-            node["attributedTo"] = JsonSerializer.SerializeToNode(AttributedTo, options.SerializerOptions);
-        if (Preview != null)
-            node["preview"] = JsonSerializer.SerializeToNode(Preview, options.SerializerOptions);
-        if (Name != null)
-            node["name"] = JsonSerializer.SerializeToNode(Name, options.SerializerOptions);
-        if (MediaType != null)
-            node["mediaType"] = JsonSerializer.SerializeToNode(MediaType, options.SerializerOptions);
-    }
-
-    public static ASType Deserialize(JsonElement element, JsonOptions options) => throw new NotSupportedException("ASType is abstract and should be deserialized through a subclass");
-    public static JsonNode Serialize(ASType obj, JsonOptions options) => throw new NotSupportedException("ASType is abstract and should be serialized through a subclass");
 }

ActivityPub.Types/ActivityPub.Types.csproj

@@ -7,7 +7,9 @@
     </PropertyGroup>
 
     <ItemGroup>
-      <PackageReference Include="System.Text.Json" Version="7.0.3" />
+        <PackageReference Include="JetBrains.Annotations" Version="2023.2.0"/>
+        <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="7.0.0"/>
+        <PackageReference Include="System.Text.Json" Version="7.0.3"/>
     </ItemGroup>
 
 </Project>

ActivityPub.Types/Internal/JsonExtensions.cs

@@ -3,7 +3,6 @@
 
 using System.Diagnostics.CodeAnalysis;
 using System.Text.Json;
-using System.Text.Json.Serialization;
 
 namespace ActivityPub.Types.Internal;
 
@@ -31,19 +30,6 @@ public static bool TryGetString(this Utf8JsonReader reader, [NotNullWhen(true)]
         return type != null;
     }
 
-    /// <summary>
-    /// Modifies the JsonSerializerOptions to remove all JsonConverters of the specified type
-    /// </summary>
-    /// <param name="options"></param>
-    /// <typeparam name="T"></typeparam>
-    /// <returns>Returns the same object for chaining</returns>
-    public static JsonSerializerOptions RemoveConvertersOfType<T>(this JsonSerializerOptions options)
-        where T : JsonConverter
-    {
-        options.Converters.RemoveWhere(c => c is T);
-        return options;
-    }
-
     /// <summary>
     /// Attempts to read the element as a string.
     /// Returns true on success.
@@ -67,37 +53,15 @@ public static bool TryGetString(this JsonElement element, [NotNullWhen(true)] ou
     /// Attempts to read the provided <see cref="JsonElement"/> as an ActivityStreams object and return its type.
     /// Returns false if the element does not contain an object or the object does not contain a valid type.
     /// </summary>
-    /// <param name="objectElement">object to read</param>
+    /// <param name="element">object to read</param>
     /// <param name="type">Set to the AS type on success, or null on failure</param>
     /// <returns>Returns true on success, false on failure</returns>
-    public static bool TryGetASType(this JsonElement objectElement, [NotNullWhen(true)] out string? type)
+    public static bool TryGetASType(this JsonElement element, [NotNullWhen(true)] out string? type)
     {
-        if (objectElement.TryGetProperty("type", out var asTypeElement) && asTypeElement.TryGetString(out type))
+        if (element.ValueKind == JsonValueKind.Object && element.TryGetProperty("type", out var asTypeElement) && asTypeElement.TryGetString(out type))
             return true;
 
         type = null;
         return false;
     }
-
-    // /// <summary>
-    // /// TODO docs
-    // /// </summary>
-    // /// <param name="element"></param>
-    // /// <param name="name"></param>
-    // /// <param name="options"></param>
-    // /// <param name="value"></param>
-    // /// <typeparam name="T"></typeparam>
-    // /// <returns></returns>
-    // /// <exception cref="JsonException"></exception>
-    // public static bool TryGetProperty<T>(this JsonElement element, string name, JsonSerializerOptions options, [NotNullWhen(true)] out T? value)
-    // {
-    //     if (!element.TryGetProperty(name, out var prop))
-    //     {
-    //         value = default;
-    //         return false;
-    //     }
-    //
-    //     value = prop.Deserialize<T>() ?? throw new JsonException($"Conversion to {typeof(T)} failed");
-    //     return true;
-    // }
 }