Add NetCord.Hosting.AzureFunctions to support serverless bots via azu…

.gitignore

@@ -364,4 +364,6 @@ FodyWeavers.xsd
 
 # Settings file
 appsettings.json
-!Documentation/**/appsettings.json
+!Documentation/**/appsettings.json
+host.json
+local.settings.json

Hosting/NetCord.Hosting.AzureFunctions/DiscordInteractionsHandler.cs

@@ -0,0 +1,149 @@
+using System.Buffers;
+using System.Net;
+using System.Text;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Azure.Functions.Worker.Http;
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Extensions.Options;
+using NetCord.Rest;
+using Microsoft.Extensions.DependencyInjection;
+namespace NetCord.Hosting.AzureFunctions;
+
+public static class ServiceCollectionExtensions
+{
+    /// <summary>
+    /// Adds the <see cref="DiscordInteractionsHandler"/> to the service collection.
+    /// </summary>
+    public static IServiceCollection AddDiscordInteractions(this IServiceCollection services)
+    {
+        services.AddSingleton<DiscordInteractionsHandler>();
+        return services;
+    }
+}
+
+public class DiscordInteractionsHandler
+{
+    private readonly IHttpInteractionHandler[] _handlers;
+    private readonly ValueTask[] _tasks;
+    private readonly HttpInteractionValidator _validator;
+    private readonly RestClient _client;
+
+    public DiscordInteractionsHandler(
+        IOptions<IDiscordOptions> options,
+        IEnumerable<IHttpInteractionHandler> handlers,
+        RestClient client)
+    {
+        var publicKey = options.Value.PublicKey ?? throw new InvalidOperationException("PublicKey must be set in IDiscordOptions.");
+        _validator = new HttpInteractionValidator(publicKey);
+        _handlers = handlers.ToArray();
+        _tasks = new ValueTask[_handlers.Length];
+        _client = client;
+    }
+
+    /// <summary>
+    /// Handles the Discord interaction request.
+    /// </summary>
+    /// <param name="req">The HTTP request data.</param>
+    /// <param name="context">The function context.</param>
+    /// <returns>The result of the interaction.</returns>
+    public async Task<HttpResponseData> HandleRequestAsync(HttpRequestData req, FunctionContext context)
+    {
+        var httpContext = context.GetHttpContext();
+        if (httpContext == null)
+        {
+            var res = req.CreateResponse(HttpStatusCode.InternalServerError);
+            await res.WriteStringAsync("HttpContext not available.").ConfigureAwait(false);
+            return res;
+        }
+
+        var interaction = await ParseInteractionAsync(httpContext, _validator, _client).ConfigureAwait(false);
+        if (interaction == null)
+        {
+            var res = req.CreateResponse(HttpStatusCode.Unauthorized);
+            return res;
+        }
+
+        HttpResponseData response = req.CreateResponse(HttpStatusCode.OK);
+
+        switch (interaction)
+        {
+            case Interaction realInteraction:
+                await HandleInteractionAsync(realInteraction, _handlers, _tasks).ConfigureAwait(false);
+                break;
+
+            case PingInteraction ping:
+                await ping.SendResponseAsync(InteractionCallback.Pong).ConfigureAwait(false);
+                break;
+
+            default:
+                response.StatusCode = HttpStatusCode.Unauthorized;
+                break;
+        }
+
+        return response;
+    }
+
+    private static async ValueTask<IInteraction?> ParseInteractionAsync(HttpContext context, HttpInteractionValidator validator, RestClient client)
+    {
+        var request = context.Request;
+
+        var headers = request.Headers;
+        if (!headers.TryGetValue("X-Signature-Ed25519", out var signatures) || !headers.TryGetValue("X-Signature-Timestamp", out var timestamps))
+        {
+            return null;
+        }
+
+        var timestamp = timestamps[0]!;
+        int timestampByteCount = Encoding.UTF8.GetByteCount(timestamp);
+
+        int timestampAndBodyLength = timestampByteCount + (int)request.ContentLength.GetValueOrDefault();
+
+        var timestampAndBodyArray = ArrayPool<byte>.Shared.Rent(timestampAndBodyLength);
+        var timestampAndBody = timestampAndBodyArray.AsMemory(0, timestampAndBodyLength);
+
+        Encoding.UTF8.GetBytes(timestamp, timestampAndBody.Span);
+
+        int position = timestampByteCount;
+        var body = request.Body;
+        while (position < timestampAndBodyLength)
+        {
+            position += await body.ReadAsync(timestampAndBody[position..]).ConfigureAwait(false);
+        }
+
+        if (!validator.Validate(signatures[0], timestampAndBody.Span))
+        {
+            return null;
+        }
+
+        var response = context.Response;
+        var interaction = HttpInteractionFactory.Create(timestampAndBody.Span[timestampByteCount..], async (interaction, interactionCallback, properties, cancellationToken) =>
+        {
+            using var content = interactionCallback.Serialize();
+            response.ContentType = content.Headers.ContentType!.ToString();
+            await content.CopyToAsync(response.Body, cancellationToken).ConfigureAwait(false);
+            await response.CompleteAsync().ConfigureAwait(false);
+        }, client);
+
+        ArrayPool<byte>.Shared.Return(timestampAndBodyArray);
+
+        return interaction;
+    }
+
+    private static async ValueTask HandleInteractionAsync(Interaction interaction, IHttpInteractionHandler[] handlers, ValueTask[] tasks)
+    {
+        int length = handlers.Length;
+
+        for (int i = 0; i < length; i++)
+#pragma warning disable CA2012
+        {
+            tasks[i] = handlers[i].HandleAsync(interaction);
+        }
+#pragma warning restore CA2012
+
+        for (int i = 0; i < length; i++)
+        {
+            await tasks[i].ConfigureAwait(false);
+        }
+    }
+}
+

Hosting/NetCord.Hosting.AzureFunctions/NetCord.Hosting.AzureFunctions.csproj

@@ -0,0 +1,37 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <LangVersion>latest</LangVersion>
+    <IsAotCompatible>true</IsAotCompatible>
+
+    <RepositoryUrl>https://github.com/NetCordDev/NetCord</RepositoryUrl>
+    <PackageProjectUrl>https://netcord.dev</PackageProjectUrl>
+    <PackageTags>bot;discord;discord-api</PackageTags>
+    <PackageIcon>SmallSquare.png</PackageIcon>
+    <PackageLicenseExpression>MIT</PackageLicenseExpression>
+    <Version>$(VersionPrefix)</Version>
+    <VersionSuffix>alpha.363</VersionSuffix>
+    <Description>The modern and fully customizable C# Discord library.</Description>
+    <PackageReadmeFile>README.md</PackageReadmeFile>
+    <GenerateDocumentationFile>true</GenerateDocumentationFile>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <None Include="..\..\Resources\NuGet\README.md" Pack="true" PackagePath="" />
+    <None Include="..\..\Resources\Logo\png\SmallSquare.png" Pack="true" PackagePath="" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.0.0" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore"
+      Version="2.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\NetCord.Hosting\NetCord.Hosting.csproj" />
+  </ItemGroup>
+</Project>

NetCord.slnx

@@ -55,6 +55,7 @@
   </Folder>
   <Folder Name="/Hosting/">
     <Project Path="Hosting/NetCord.Hosting.AspNetCore/NetCord.Hosting.AspNetCore.csproj" />
+    <Project Path="Hosting/NetCord.Hosting.AzureFunctions/NetCord.Hosting.AzureFunctions.csproj" />
     <Project Path="Hosting/NetCord.Hosting.Services/NetCord.Hosting.Services.csproj" />
     <Project Path="Hosting/NetCord.Hosting/NetCord.Hosting.csproj" />
   </Folder>
@@ -71,6 +72,7 @@
     <Project Path="Tests/ColorTest/ColorTest.csproj" />
     <Project Path="Tests/MentionTest/MentionTest.csproj" />
     <Project Path="Tests/NetCord.Test.Hosting.AspNetCore/NetCord.Test.Hosting.AspNetCore.csproj" />
+    <Project Path="Tests/NetCord.Test.Hosting.AzureFunctions/NetCord.Test.Hosting.AzureFunctions.csproj" />
     <Project Path="Tests/NetCord.Test.Hosting/NetCord.Test.Hosting.csproj" />
     <Project Path="Tests/NetCord.Test.Sharded.Hosting/NetCord.Test.Sharded.Hosting.csproj" />
     <Project Path="Tests/NetCord.Test.Sharded/NetCord.Test.Sharded.csproj" />

Tests/NetCord.Test.Hosting.AzureFunctions/Interactions.cs

@@ -0,0 +1,16 @@
+using Microsoft.Azure.Functions.Worker;
+using Microsoft.Azure.Functions.Worker.Http;
+
+using NetCord.Hosting.AzureFunctions;
+
+namespace NetCord.Test.Hosting.AzureFunctions;
+
+public class Interactions(DiscordInteractionsHandler handler)
+{
+    [Function("interactions")]
+    public async Task<HttpResponseData> Run([HttpTrigger(AuthorizationLevel.Anonymous, "post")] HttpRequestData req, FunctionContext context)
+    {
+        var res = await handler.HandleRequestAsync(req, context).ConfigureAwait(false);
+        return res;
+    }
+}

Tests/NetCord.Test.Hosting.AzureFunctions/NetCord.Test.Hosting.AzureFunctions.csproj

@@ -0,0 +1,42 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+      <TargetFramework>net8.0</TargetFramework>
+      <AzureFunctionsVersion>v4</AzureFunctionsVersion>
+      <OutputType>Exe</OutputType>
+      <ImplicitUsings>enable</ImplicitUsings>
+      <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <ProjectReference
+      Include="..\..\Hosting\NetCord.Hosting.AzureFunctions\NetCord.Hosting.AzureFunctions.csproj" />
+    <ProjectReference
+      Include="..\..\Hosting\NetCord.Hosting.Services\NetCord.Hosting.Services.csproj" />
+    <ProjectReference Include="..\..\Hosting\NetCord.Hosting\NetCord.Hosting.csproj" />
+  </ItemGroup>
+
+  <ItemGroup>
+      <PackageReference Include="libsodium" Version="1.0.20" />
+
+      <FrameworkReference Include="Microsoft.AspNetCore.App" />
+      <PackageReference Include="Microsoft.Azure.Functions.Worker" Version="2.0.0" />
+      <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http" Version="3.2.0" />
+      <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version="2.0.0" />
+      <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" Version="2.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Update="host.json" Condition="Exists('host.json')">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+
+    <None Update="local.settings.json" Condition="Exists('local.settings.json')">
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
+    <ItemGroup>
+        <Using Include="System.Threading.ExecutionContext" Alias="ExecutionContext" />
+    </ItemGroup>
+</Project>

Tests/NetCord.Test.Hosting.AzureFunctions/Program.cs

@@ -0,0 +1,23 @@
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+using NetCord;
+using NetCord.Hosting;
+using NetCord.Hosting.AzureFunctions;
+using NetCord.Hosting.Rest;
+using NetCord.Hosting.Services.ApplicationCommands;
+
+var host = new HostBuilder()
+    .ConfigureFunctionsWebApplication()
+    .ConfigureServices((context, services) =>
+    {
+        services.AddDiscordRest();
+        services.AddHttpApplicationCommands();
+        services.AddDiscordInteractions();
+    })
+    .Build();
+
+host.AddSlashCommand("ping", "Ping!", () => "Pong!");
+
+host.Run();

Tests/NetCord.Test.Hosting.AzureFunctions/Properties/launchSettings.json

@@ -0,0 +1,9 @@
+{
+  "profiles": {
+    "NetCord.Test.Hosting.AzureFunctions": {
+      "commandName": "Project",
+      "commandLineArgs": "--port 7048",
+      "launchBrowser": false
+    }
+  }
+}

Tests/NetCord.Test.Hosting.AzureFunctions/Properties/serviceDependencies.json

@@ -0,0 +1,8 @@
+{
+  "dependencies": {
+    "storage1": {
+      "type": "storage",
+      "connectionId": "AzureWebJobsStorage"
+    }
+  }
+}