feat(identity): add /users/@me endpoint

.editorconfig

@@ -2,3 +2,6 @@
 
 # CS9113: Parameter is unread.
 dotnet_diagnostic.CS9113.severity = silent
+
+# EntityFramework.ModelValidation.UnlimitedStringLength
+resharper_entity_framework_model_validation_unlimited_string_length_highlighting=none

.gitignore

@@ -1,3 +1,47 @@
 bin/
 obj/
 .version
+
+# Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
+# Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
+
+# User-specific stuff
+.idea/**/workspace.xml
+.idea/**/tasks.xml
+.idea/**/usage.statistics.xml
+.idea/**/dictionaries
+.idea/**/shelf
+.idea/**/discord.xml
+
+# Generated files
+.idea/**/contentModel.xml
+
+# Sensitive or high-churn files
+.idea/**/dataSources/
+.idea/**/dataSources.ids
+.idea/**/dataSources.local.xml
+.idea/**/sqlDataSources.xml
+.idea/**/dynamic.xml
+.idea/**/uiDesigner.xml
+.idea/**/dbnavigator.xml
+
+# Gradle
+.idea/**/gradle.xml
+.idea/**/libraries
+
+# CMake
+cmake-build-*/
+
+# File-based project format
+*.iws
+
+# Editor-based Rest Client
+.idea/httpRequests
+
+# Visual Studio Code
+.vscode/*
+!.vscode/settings.json
+!.vscode/tasks.json
+!.vscode/launch.json
+!.vscode/extensions.json
+!.vscode/*.code-snippets

.idea/.idea.Foxchat/.idea/.gitignore

@@ -0,0 +1,13 @@
+# Default ignored files
+/shelf/
+/workspace.xml
+# Rider ignored files
+/.idea.Foxchat.iml
+/contentModel.xml
+/modules.xml
+/projectSettingsUpdater.xml
+# Editor-based HTTP Client requests
+/httpRequests/
+# Datasource local storage ignored files
+/dataSources/
+/dataSources.local.xml

.idea/.idea.Foxchat/.idea/.name

@@ -0,0 +1 @@
+Foxchat

.idea/.idea.Foxchat/.idea/encodings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Encoding" addBOMForNewFiles="with BOM under Windows, with no BOM otherwise" />
+</project>

.idea/.idea.Foxchat/.idea/indexLayout.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="UserContentModel">
+    <attachedFolders />
+    <explicitIncludes />
+    <explicitExcludes />
+  </component>
+</project>

.idea/.idea.Foxchat/.idea/sqldialects.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="SqlDialectMappings">
+    <file url="file://$PROJECT_DIR$/Foxchat.Chat/Migrations/20240521132416_Init.cs" dialect="PostgreSQL" />
+    <file url="PROJECT" dialect="PostgreSQL" />
+  </component>
+</project>

.idea/.idea.Foxchat/.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

Foxchat.Chat/Controllers/Api/GuildsController.cs

@@ -0,0 +1,84 @@
+using Foxchat.Chat.Database;
+using Foxchat.Chat.Database.Models;
+using Foxchat.Chat.Middleware;
+using Foxchat.Chat.Services;
+using Foxchat.Core.Models;
+using Foxchat.Core.Models.Http;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using ApiError = Foxchat.Core.ApiError;
+
+namespace Foxchat.Chat.Controllers.Api;
+
+[ApiController]
+[Route("/_fox/chat/guilds")]
+public class GuildsController(ILogger logger, ChatContext db, UserResolverService userResolverService) : ControllerBase
+{
+    [HttpPost]
+    public async Task<IActionResult> CreateGuild([FromBody] GuildsApi.CreateGuildRequest req)
+    {
+        var (instance, _, userId) = HttpContext.GetSignatureWithUser();
+
+        var user = await userResolverService.ResolveUserAsync(instance, userId);
+
+        var guild = new Guild
+        {
+            Name = req.Name,
+            Owner = user,
+        };
+        db.Add(guild);
+        guild.Users.Add(user);
+        var defaultChannel = new Channel
+        {
+            Guild = guild,
+            Name = "general"
+        };
+        db.Add(defaultChannel);
+
+        await db.SaveChangesAsync();
+
+        return Ok(new Guilds.Guild(
+            guild.Id.ToString(),
+            guild.Name,
+            [user.Id.ToString()],
+            [new Channels.PartialChannel(defaultChannel.Id.ToString(), defaultChannel.Name)])
+        );
+    }
+
+    [HttpGet("{id}")]
+    public async Task<IActionResult> GetGuild(Ulid id)
+    {
+        var (instance, _, userId) = HttpContext.GetSignatureWithUser();
+        var guild = await db.Guilds
+            .Include(g => g.Channels)
+            .FirstOrDefaultAsync(g =>
+                g.Id == id && g.Users.Any(u => u.RemoteUserId == userId && u.InstanceId == instance.Id));
+        if (guild == null) throw new ApiError.NotFound("Guild not found");
+
+        return Ok(new Guilds.Guild(
+            guild.Id.ToString(),
+            guild.Name,
+            [guild.OwnerId.ToString()],
+            guild.Channels.Select(c => new Channels.PartialChannel(c.Id.ToString(), c.Name))
+        ));
+    }
+
+    [HttpGet("@me")]
+    public async Task<IActionResult> GetUserGuilds()
+    {
+        var (instance, _, userId) = HttpContext.GetSignatureWithUser();
+        var guilds = await db.Guilds
+            .Include(g => g.Channels)
+            .Where(g => g.Users.Any(u => u.RemoteUserId == userId && u.InstanceId == instance.Id))
+            .ToListAsync();
+
+        var guildResponses = guilds.Select(g => new Guilds.Guild(
+            g.Id.ToString(),
+            g.Name,
+            [g.OwnerId.ToString()],
+            g.Channels.Select(c => new Channels.PartialChannel(c.Id.ToString(), c.Name))
+        ));
+
+        return Ok(guildResponses);
+    }
+}

Foxchat.Chat/Controllers/HelloController.cs

@@ -0,0 +1,47 @@
+using Foxchat.Chat.Database;
+using Foxchat.Chat.Database.Models;
+using Foxchat.Chat.Middleware;
+using Foxchat.Core.Extensions;
+using Foxchat.Core.Federation;
+using Foxchat.Core.Models.Http;
+using Microsoft.AspNetCore.Mvc;
+using ApiError = Foxchat.Core.ApiError;
+
+namespace Foxchat.Chat.Controllers;
+
+[ApiController]
+[ServerUnauthenticated]
+[Route("/_fox/chat/hello")]
+public class HelloController(
+    ILogger logger,
+    ChatContext db,
+    InstanceConfig config,
+    RequestSigningService requestSigningService)
+    : ControllerBase
+{
+    [HttpPost]
+    public async Task<IActionResult> Hello([FromBody] Hello.HelloRequest req)
+    {
+        var node = await requestSigningService.RequestAsync<Hello.NodeInfo>(HttpMethod.Get, req.Host,
+            "/_fox/ident/node");
+
+        if (!HttpContext.ExtractRequestData(out var signature, out var domain, out var signatureData))
+            throw new ApiError.IncomingFederationError("This endpoint requires signed requests.");
+        if (domain != req.Host)
+            throw new ApiError.IncomingFederationError("Host is invalid.");
+
+        if (!requestSigningService.VerifySignature(node.PublicKey, signature, signatureData))
+            throw new ApiError.IncomingFederationError("Signature is not valid.");
+
+        var instance = await db.GetInstanceAsync();
+        db.IdentityInstances.Add(new IdentityInstance
+        {
+            Domain = req.Host,
+            BaseUrl = $"https://{req.Host}",
+            PublicKey = node.PublicKey
+        });
+        await db.SaveChangesAsync();
+
+        return Ok(new Hello.HelloResponse(instance.PublicKey, config.Domain));
+    }
+}

Foxchat.Chat/Database/BaseModel.cs

@@ -0,0 +1,6 @@
+namespace Foxchat.Chat.Database;
+
+public abstract class BaseModel
+{
+    public Ulid Id { get; init; } = Ulid.NewUlid();
+}

Foxchat.Chat/Database/ChatContext.cs

@@ -1,5 +1,7 @@
+using Foxchat.Chat.Database.Models;
 using Foxchat.Core;
 using Foxchat.Core.Database;
+using Foxchat.Core.Extensions;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Design;
 using Npgsql;
@@ -9,10 +11,16 @@ namespace Foxchat.Chat.Database;
 public class ChatContext : IDatabaseContext
 {
     private readonly NpgsqlDataSource _dataSource;
+    private readonly ILoggerFactory? _loggerFactory;
 
     public override DbSet<Instance> Instance { get; set; }
+    public DbSet<IdentityInstance> IdentityInstances { get; set; }
+    public DbSet<User> Users { get; set; }
+    public DbSet<Guild> Guilds { get; set; }
+    public DbSet<Channel> Channels { get; set; }
+    public DbSet<Message> Messages { get; set; }
 
-    public ChatContext(InstanceConfig config)
+    public ChatContext(InstanceConfig config, ILoggerFactory? loggerFactory)
     {
         var connString = new NpgsqlConnectionStringBuilder(config.Database.Url)
         {
@@ -23,12 +31,14 @@ public class ChatContext : IDatabaseContext
         var dataSourceBuilder = new NpgsqlDataSourceBuilder(connString);
         dataSourceBuilder.UseNodaTime();
         _dataSource = dataSourceBuilder.Build();
+        _loggerFactory = loggerFactory;
     }
 
     protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
-            => optionsBuilder
-                .UseNpgsql(_dataSource, o => o.UseNodaTime())
-                .UseSnakeCaseNamingConvention();
+        => optionsBuilder
+            .UseNpgsql(_dataSource, o => o.UseNodaTime())
+            .UseSnakeCaseNamingConvention()
+            .UseLoggerFactory(_loggerFactory);
 
     protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
     {
@@ -38,20 +48,35 @@ public class ChatContext : IDatabaseContext
 
     protected override void OnModelCreating(ModelBuilder modelBuilder)
     {
+        modelBuilder.Entity<IdentityInstance>().HasIndex(i => i.Domain).IsUnique();
+
+        modelBuilder.Entity<User>().HasIndex(u => new { u.RemoteUserId, u.InstanceId }).IsUnique();
+        modelBuilder.Entity<User>().HasIndex(u => new { u.Username, u.InstanceId }).IsUnique();
+
+        modelBuilder.Entity<Guild>()
+            .HasOne(e => e.Owner)
+            .WithMany(e => e.OwnedGuilds)
+            .HasForeignKey(e => e.OwnerId)
+            .IsRequired();
+
+        modelBuilder.Entity<User>()
+            .HasMany(e => e.Guilds)
+            .WithMany(e => e.Users);
     }
 }
 
+// ReSharper disable once UnusedType.Global
 public class DesignTimeIdentityContextFactory : IDesignTimeDbContextFactory<ChatContext>
 {
     public ChatContext CreateDbContext(string[] args)
     {
         // Read the configuration file
         var config = new ConfigurationBuilder()
-            .AddConfiguration("identity.ini")
+            .AddConfiguration("chat.ini")
             .Build()
             // Get the configuration as our config class
             .Get<InstanceConfig>() ?? new();
 
-        return new ChatContext(config);
+        return new ChatContext(config, null);
     }
-}
+}

Foxchat.Chat/Database/Models/Channel.cs

@@ -0,0 +1,9 @@
+namespace Foxchat.Chat.Database.Models;
+
+public class Channel : BaseModel
+{
+    public Ulid GuildId { get; init; }
+    public Guild Guild { get; init; } = null!;
+    public string Name { get; set; } = null!;
+    public string? Topic { get; set; }
+}

Foxchat.Chat/Database/Models/Guild.cs

@@ -0,0 +1,11 @@
+namespace Foxchat.Chat.Database.Models;
+
+public class Guild : BaseModel
+{
+    public string Name { get; set; } = null!;
+    public Ulid OwnerId { get; set; }
+    public User Owner { get; set; } = null!;
+
+    public List<User> Users { get; } = [];
+    public List<Channel> Channels { get; } = [];
+}

Foxchat.Chat/Database/Models/IdentityInstance.cs

@@ -0,0 +1,17 @@
+namespace Foxchat.Chat.Database.Models;
+
+public class IdentityInstance : BaseModel
+{
+    public string Domain { get; init; } = null!;
+    public string BaseUrl { get; init; } = null!;
+    public string PublicKey { get; init; } = null!;
+
+    public InstanceStatus Status { get; set; } = InstanceStatus.Active;
+    public string? Reason { get; set; }
+
+    public enum InstanceStatus
+    {
+        Active,
+        Suspended,
+    }
+}

Foxchat.Chat/Database/Models/Message.cs

@@ -0,0 +1,15 @@
+using NodaTime;
+
+namespace Foxchat.Chat.Database.Models;
+
+public class Message : BaseModel
+{
+    public Ulid ChannelId { get; init; }
+    public Channel Channel { get; init; } = null!;
+    public Ulid AuthorId { get; init; }
+    public User Author { get; init; } = null!;
+    
+    public string? Content { get; set; }
+    
+    public Instant? UpdatedAt { get; set; }
+}

Foxchat.Chat/Database/Models/User.cs

@@ -0,0 +1,18 @@
+using Foxchat.Core.Models;
+using NodaTime;
+
+namespace Foxchat.Chat.Database.Models;
+
+public class User : BaseModel
+{
+    public Ulid InstanceId { get; init; }
+    public IdentityInstance Instance { get; init; } = null!;
+    public string RemoteUserId { get; init; } = null!;
+    public string Username { get; init; } = null!;
+
+    public string? Avatar { get; set; }
+    public Instant LastFetchedAt { get; set; }
+
+    public List<Guild> Guilds { get; } = [];
+    public List<Guild> OwnedGuilds { get; } = [];
+}

Foxchat.Chat/Extensions/WebApplicationExtensions.cs

@@ -0,0 +1,28 @@
+using Foxchat.Chat.Middleware;
+using Foxchat.Chat.Services;
+using Foxchat.Core.Middleware;
+
+namespace Foxchat.Chat.Extensions;
+
+public static class WebApplicationExtensions
+{
+    public static IServiceCollection AddCustomMiddleware(this IServiceCollection services)
+    {
+        return services
+            .AddScoped<ErrorHandlerMiddleware>()
+            .AddScoped<ServerAuthenticationMiddleware>();
+    }
+
+    public static IApplicationBuilder UseCustomMiddleware(this IApplicationBuilder app)
+    {
+        return app
+            .UseMiddleware<ErrorHandlerMiddleware>()
+            .UseMiddleware<ServerAuthenticationMiddleware>();
+    }
+
+    public static IServiceCollection AddChatServices(this IServiceCollection services)
+    {
+        return services
+            .AddScoped<UserResolverService>();
+    }
+}

Foxchat.Chat/Middleware/ServerAuthenticationMiddleware.cs

@@ -0,0 +1,86 @@
+using Foxchat.Chat.Database;
+using Foxchat.Chat.Database.Models;
+using Foxchat.Core;
+using Foxchat.Core.Extensions;
+using Foxchat.Core.Federation;
+using Microsoft.EntityFrameworkCore;
+
+namespace Foxchat.Chat.Middleware;
+
+public class ServerAuthenticationMiddleware(ILogger logger, ChatContext db, RequestSigningService requestSigningService)
+    : IMiddleware
+{
+    public async Task InvokeAsync(HttpContext ctx, RequestDelegate next)
+    {
+        var endpoint = ctx.GetEndpoint();
+        // Endpoints require server authentication by default, unless they have the [Unauthenticated] attribute.
+        var metadata = endpoint?.Metadata.GetMetadata<ServerUnauthenticatedAttribute>();
+        if (metadata != null)
+        {
+            await next(ctx);
+            return;
+        }
+
+        if (!ctx.ExtractRequestData(out var signature, out var domain, out var signatureData))
+            throw new ApiError.IncomingFederationError("This endpoint requires signed requests.");
+
+        var instance = await GetInstanceAsync(domain);
+
+        if (!requestSigningService.VerifySignature(instance.PublicKey, signature, signatureData))
+            throw new ApiError.IncomingFederationError("Signature is not valid.");
+        
+        ctx.SetSignature(instance, signatureData);
+
+        await next(ctx);
+    }
+
+    private async Task<IdentityInstance> GetInstanceAsync(string domain)
+    {
+        return await db.IdentityInstances.FirstOrDefaultAsync(i => i.Domain == domain)
+               ?? throw new ApiError.IncomingFederationError("Remote instance is not known.");
+    }
+}
+
+/// <summary>
+/// Attribute to be put on controllers or methods to indicate that it does <i>not</i> require a signed request.
+/// </summary>
+[AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
+public class ServerUnauthenticatedAttribute : Attribute;
+
+public static class HttpContextExtensions
+{
+    private const string Key = "instance";
+
+    public static void SetSignature(this HttpContext ctx, IdentityInstance instance, SignatureData data)
+    {
+        ctx.Items.Add(Key, (instance, data));
+    }
+
+    public static (IdentityInstance?, SignatureData?) GetSignature(this HttpContext ctx)
+    {
+        try
+        {
+            var obj = ctx.GetSignatureOrThrow();
+            return (obj.Item1, obj.Item2);
+        }
+        catch
+        {
+            return (null, null);
+        }
+    }
+
+    public static (IdentityInstance, SignatureData) GetSignatureOrThrow(this HttpContext ctx)
+    {
+        if (!ctx.Items.TryGetValue(Key, out var obj))
+            throw new ApiError.AuthenticationError("No instance in HttpContext");
+
+        return ((IdentityInstance, SignatureData))obj!;
+    }
+
+    public static (IdentityInstance, SignatureData, string) GetSignatureWithUser(this HttpContext ctx)
+    {
+        var (instance, sig) = ctx.GetSignatureOrThrow();
+        if (sig.UserId == null) throw new ApiError.IncomingFederationError("This endpoint requires a user ID.");
+        return (instance, sig, sig.UserId);
+    }
+}

Foxchat.Chat/Migrations/20240521132416_Init.Designer.cs

@@ -0,0 +1,325 @@
+// <auto-generated />
+using System;
+using Foxchat.Chat.Database;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using NodaTime;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Foxchat.Chat.Migrations
+{
+    [DbContext(typeof(ChatContext))]
+    [Migration("20240521132416_Init")]
+    partial class Init
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.5")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("GuildId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guild_id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<string>("Topic")
+                        .HasColumnType("text")
+                        .HasColumnName("topic");
+
+                    b.HasKey("Id")
+                        .HasName("pk_channels");
+
+                    b.HasIndex("GuildId")
+                        .HasDatabaseName("ix_channels_guild_id");
+
+                    b.ToTable("channels", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<Guid>("OwnerId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("owner_id");
+
+                    b.HasKey("Id")
+                        .HasName("pk_guilds");
+
+                    b.HasIndex("OwnerId")
+                        .HasDatabaseName("ix_guilds_owner_id");
+
+                    b.ToTable("guilds", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.IdentityInstance", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("BaseUrl")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("base_url");
+
+                    b.Property<string>("Domain")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("domain");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.Property<string>("Reason")
+                        .HasColumnType("text")
+                        .HasColumnName("reason");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer")
+                        .HasColumnName("status");
+
+                    b.HasKey("Id")
+                        .HasName("pk_identity_instances");
+
+                    b.HasIndex("Domain")
+                        .IsUnique()
+                        .HasDatabaseName("ix_identity_instances_domain");
+
+                    b.ToTable("identity_instances", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("AuthorId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("author_id");
+
+                    b.Property<Guid>("ChannelId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("channel_id");
+
+                    b.Property<string>("Content")
+                        .HasColumnType("text")
+                        .HasColumnName("content");
+
+                    b.Property<Instant?>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("updated_at");
+
+                    b.HasKey("Id")
+                        .HasName("pk_messages");
+
+                    b.HasIndex("AuthorId")
+                        .HasDatabaseName("ix_messages_author_id");
+
+                    b.HasIndex("ChannelId")
+                        .HasDatabaseName("ix_messages_channel_id");
+
+                    b.ToTable("messages", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Avatar")
+                        .HasColumnType("text")
+                        .HasColumnName("avatar");
+
+                    b.Property<Guid>("InstanceId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("instance_id");
+
+                    b.Property<string>("RemoteUserId")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("remote_user_id");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("username");
+
+                    b.HasKey("Id")
+                        .HasName("pk_users");
+
+                    b.HasIndex("InstanceId")
+                        .HasDatabaseName("ix_users_instance_id");
+
+                    b.HasIndex("RemoteUserId", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_remote_user_id_instance_id");
+
+                    b.HasIndex("Username", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_username_instance_id");
+
+                    b.ToTable("users", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Core.Database.Instance", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasColumnName("id");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("PrivateKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("private_key");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.HasKey("Id")
+                        .HasName("pk_instance");
+
+                    b.ToTable("instance", (string)null);
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.Property<Guid>("GuildsId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guilds_id");
+
+                    b.Property<Guid>("UsersId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("users_id");
+
+                    b.HasKey("GuildsId", "UsersId")
+                        .HasName("pk_guild_user");
+
+                    b.HasIndex("UsersId")
+                        .HasDatabaseName("ix_guild_user_users_id");
+
+                    b.ToTable("guild_user", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", "Guild")
+                        .WithMany("Channels")
+                        .HasForeignKey("GuildId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_channels_guilds_guild_id");
+
+                    b.Navigation("Guild");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Owner")
+                        .WithMany("OwnedGuilds")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guilds_users_owner_id");
+
+                    b.Navigation("Owner");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Author")
+                        .WithMany()
+                        .HasForeignKey("AuthorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_users_author_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.Channel", "Channel")
+                        .WithMany()
+                        .HasForeignKey("ChannelId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_channels_channel_id");
+
+                    b.Navigation("Author");
+
+                    b.Navigation("Channel");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.IdentityInstance", "Instance")
+                        .WithMany()
+                        .HasForeignKey("InstanceId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_users_identity_instances_instance_id");
+
+                    b.Navigation("Instance");
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", null)
+                        .WithMany()
+                        .HasForeignKey("GuildsId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_guilds_guilds_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UsersId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_users_users_id");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Navigation("Channels");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Navigation("OwnedGuilds");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Foxchat.Chat/Migrations/20240521132416_Init.cs

@@ -0,0 +1,228 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+using NodaTime;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Foxchat.Chat.Migrations
+{
+    /// <inheritdoc />
+    public partial class Init : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "identity_instances",
+                columns: table => new
+                {
+                    id = table.Column<Guid>(type: "uuid", nullable: false),
+                    domain = table.Column<string>(type: "text", nullable: false),
+                    base_url = table.Column<string>(type: "text", nullable: false),
+                    public_key = table.Column<string>(type: "text", nullable: false),
+                    status = table.Column<int>(type: "integer", nullable: false),
+                    reason = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_identity_instances", x => x.id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "instance",
+                columns: table => new
+                {
+                    id = table.Column<int>(type: "integer", nullable: false)
+                        .Annotation("Npgsql:ValueGenerationStrategy", NpgsqlValueGenerationStrategy.IdentityByDefaultColumn),
+                    public_key = table.Column<string>(type: "text", nullable: false),
+                    private_key = table.Column<string>(type: "text", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_instance", x => x.id);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "users",
+                columns: table => new
+                {
+                    id = table.Column<Guid>(type: "uuid", nullable: false),
+                    instance_id = table.Column<Guid>(type: "uuid", nullable: false),
+                    remote_user_id = table.Column<string>(type: "text", nullable: false),
+                    username = table.Column<string>(type: "text", nullable: false),
+                    avatar = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_users", x => x.id);
+                    table.ForeignKey(
+                        name: "fk_users_identity_instances_instance_id",
+                        column: x => x.instance_id,
+                        principalTable: "identity_instances",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "guilds",
+                columns: table => new
+                {
+                    id = table.Column<Guid>(type: "uuid", nullable: false),
+                    name = table.Column<string>(type: "text", nullable: false),
+                    owner_id = table.Column<Guid>(type: "uuid", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_guilds", x => x.id);
+                    table.ForeignKey(
+                        name: "fk_guilds_users_owner_id",
+                        column: x => x.owner_id,
+                        principalTable: "users",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "channels",
+                columns: table => new
+                {
+                    id = table.Column<Guid>(type: "uuid", nullable: false),
+                    guild_id = table.Column<Guid>(type: "uuid", nullable: false),
+                    name = table.Column<string>(type: "text", nullable: false),
+                    topic = table.Column<string>(type: "text", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_channels", x => x.id);
+                    table.ForeignKey(
+                        name: "fk_channels_guilds_guild_id",
+                        column: x => x.guild_id,
+                        principalTable: "guilds",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "guild_user",
+                columns: table => new
+                {
+                    guilds_id = table.Column<Guid>(type: "uuid", nullable: false),
+                    users_id = table.Column<Guid>(type: "uuid", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_guild_user", x => new { x.guilds_id, x.users_id });
+                    table.ForeignKey(
+                        name: "fk_guild_user_guilds_guilds_id",
+                        column: x => x.guilds_id,
+                        principalTable: "guilds",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                    table.ForeignKey(
+                        name: "fk_guild_user_users_users_id",
+                        column: x => x.users_id,
+                        principalTable: "users",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "messages",
+                columns: table => new
+                {
+                    id = table.Column<Guid>(type: "uuid", nullable: false),
+                    channel_id = table.Column<Guid>(type: "uuid", nullable: false),
+                    author_id = table.Column<Guid>(type: "uuid", nullable: false),
+                    content = table.Column<string>(type: "text", nullable: true),
+                    updated_at = table.Column<Instant>(type: "timestamp with time zone", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("pk_messages", x => x.id);
+                    table.ForeignKey(
+                        name: "fk_messages_channels_channel_id",
+                        column: x => x.channel_id,
+                        principalTable: "channels",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                    table.ForeignKey(
+                        name: "fk_messages_users_author_id",
+                        column: x => x.author_id,
+                        principalTable: "users",
+                        principalColumn: "id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "ix_channels_guild_id",
+                table: "channels",
+                column: "guild_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_guild_user_users_id",
+                table: "guild_user",
+                column: "users_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_guilds_owner_id",
+                table: "guilds",
+                column: "owner_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_identity_instances_domain",
+                table: "identity_instances",
+                column: "domain",
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "ix_messages_author_id",
+                table: "messages",
+                column: "author_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_messages_channel_id",
+                table: "messages",
+                column: "channel_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_users_instance_id",
+                table: "users",
+                column: "instance_id");
+
+            migrationBuilder.CreateIndex(
+                name: "ix_users_remote_user_id_instance_id",
+                table: "users",
+                columns: new[] { "remote_user_id", "instance_id" },
+                unique: true);
+
+            // EF Core doesn't support creating indexes on arbitrary expressions, so we have to create it manually.
+            migrationBuilder.Sql("CREATE UNIQUE INDEX ix_users_username_instance_id ON users (lower(username), instance_id)");
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "guild_user");
+
+            migrationBuilder.DropTable(
+                name: "instance");
+
+            migrationBuilder.DropTable(
+                name: "messages");
+
+            migrationBuilder.DropTable(
+                name: "channels");
+
+            migrationBuilder.DropTable(
+                name: "guilds");
+
+            migrationBuilder.DropTable(
+                name: "users");
+
+            migrationBuilder.DropTable(
+                name: "identity_instances");
+        }
+    }
+}

Foxchat.Chat/Migrations/20240521191115_AddLastFetchedAtToUsers.Designer.cs

@@ -0,0 +1,329 @@
+// <auto-generated />
+using System;
+using Foxchat.Chat.Database;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using NodaTime;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Foxchat.Chat.Migrations
+{
+    [DbContext(typeof(ChatContext))]
+    [Migration("20240521191115_AddLastFetchedAtToUsers")]
+    partial class AddLastFetchedAtToUsers
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.5")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("GuildId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guild_id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<string>("Topic")
+                        .HasColumnType("text")
+                        .HasColumnName("topic");
+
+                    b.HasKey("Id")
+                        .HasName("pk_channels");
+
+                    b.HasIndex("GuildId")
+                        .HasDatabaseName("ix_channels_guild_id");
+
+                    b.ToTable("channels", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<Guid>("OwnerId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("owner_id");
+
+                    b.HasKey("Id")
+                        .HasName("pk_guilds");
+
+                    b.HasIndex("OwnerId")
+                        .HasDatabaseName("ix_guilds_owner_id");
+
+                    b.ToTable("guilds", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.IdentityInstance", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("BaseUrl")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("base_url");
+
+                    b.Property<string>("Domain")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("domain");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.Property<string>("Reason")
+                        .HasColumnType("text")
+                        .HasColumnName("reason");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer")
+                        .HasColumnName("status");
+
+                    b.HasKey("Id")
+                        .HasName("pk_identity_instances");
+
+                    b.HasIndex("Domain")
+                        .IsUnique()
+                        .HasDatabaseName("ix_identity_instances_domain");
+
+                    b.ToTable("identity_instances", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("AuthorId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("author_id");
+
+                    b.Property<Guid>("ChannelId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("channel_id");
+
+                    b.Property<string>("Content")
+                        .HasColumnType("text")
+                        .HasColumnName("content");
+
+                    b.Property<Instant?>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("updated_at");
+
+                    b.HasKey("Id")
+                        .HasName("pk_messages");
+
+                    b.HasIndex("AuthorId")
+                        .HasDatabaseName("ix_messages_author_id");
+
+                    b.HasIndex("ChannelId")
+                        .HasDatabaseName("ix_messages_channel_id");
+
+                    b.ToTable("messages", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Avatar")
+                        .HasColumnType("text")
+                        .HasColumnName("avatar");
+
+                    b.Property<Guid>("InstanceId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("instance_id");
+
+                    b.Property<Instant>("LastFetchedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("last_fetched_at");
+
+                    b.Property<string>("RemoteUserId")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("remote_user_id");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("username");
+
+                    b.HasKey("Id")
+                        .HasName("pk_users");
+
+                    b.HasIndex("InstanceId")
+                        .HasDatabaseName("ix_users_instance_id");
+
+                    b.HasIndex("RemoteUserId", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_remote_user_id_instance_id");
+
+                    b.HasIndex("Username", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_username_instance_id");
+
+                    b.ToTable("users", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Core.Database.Instance", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasColumnName("id");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("PrivateKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("private_key");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.HasKey("Id")
+                        .HasName("pk_instance");
+
+                    b.ToTable("instance", (string)null);
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.Property<Guid>("GuildsId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guilds_id");
+
+                    b.Property<Guid>("UsersId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("users_id");
+
+                    b.HasKey("GuildsId", "UsersId")
+                        .HasName("pk_guild_user");
+
+                    b.HasIndex("UsersId")
+                        .HasDatabaseName("ix_guild_user_users_id");
+
+                    b.ToTable("guild_user", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", "Guild")
+                        .WithMany("Channels")
+                        .HasForeignKey("GuildId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_channels_guilds_guild_id");
+
+                    b.Navigation("Guild");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Owner")
+                        .WithMany("OwnedGuilds")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guilds_users_owner_id");
+
+                    b.Navigation("Owner");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Author")
+                        .WithMany()
+                        .HasForeignKey("AuthorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_users_author_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.Channel", "Channel")
+                        .WithMany()
+                        .HasForeignKey("ChannelId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_channels_channel_id");
+
+                    b.Navigation("Author");
+
+                    b.Navigation("Channel");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.IdentityInstance", "Instance")
+                        .WithMany()
+                        .HasForeignKey("InstanceId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_users_identity_instances_instance_id");
+
+                    b.Navigation("Instance");
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", null)
+                        .WithMany()
+                        .HasForeignKey("GuildsId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_guilds_guilds_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UsersId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_users_users_id");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Navigation("Channels");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Navigation("OwnedGuilds");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Foxchat.Chat/Migrations/20240521191115_AddLastFetchedAtToUsers.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+using NodaTime;
+
+#nullable disable
+
+namespace Foxchat.Chat.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddLastFetchedAtToUsers : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<Instant>(
+                name: "last_fetched_at",
+                table: "users",
+                type: "timestamp with time zone",
+                nullable: false,
+                defaultValue: NodaTime.Instant.FromUnixTimeTicks(0L));
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "last_fetched_at",
+                table: "users");
+        }
+    }
+}

Foxchat.Chat/Migrations/ChatContextModelSnapshot.cs

@@ -0,0 +1,326 @@
+// <auto-generated />
+using System;
+using Foxchat.Chat.Database;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using NodaTime;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+
+#nullable disable
+
+namespace Foxchat.Chat.Migrations
+{
+    [DbContext(typeof(ChatContext))]
+    partial class ChatContextModelSnapshot : ModelSnapshot
+    {
+        protected override void BuildModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.5")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("GuildId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guild_id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<string>("Topic")
+                        .HasColumnType("text")
+                        .HasColumnName("topic");
+
+                    b.HasKey("Id")
+                        .HasName("pk_channels");
+
+                    b.HasIndex("GuildId")
+                        .HasDatabaseName("ix_channels_guild_id");
+
+                    b.ToTable("channels", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("name");
+
+                    b.Property<Guid>("OwnerId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("owner_id");
+
+                    b.HasKey("Id")
+                        .HasName("pk_guilds");
+
+                    b.HasIndex("OwnerId")
+                        .HasDatabaseName("ix_guilds_owner_id");
+
+                    b.ToTable("guilds", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.IdentityInstance", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("BaseUrl")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("base_url");
+
+                    b.Property<string>("Domain")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("domain");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.Property<string>("Reason")
+                        .HasColumnType("text")
+                        .HasColumnName("reason");
+
+                    b.Property<int>("Status")
+                        .HasColumnType("integer")
+                        .HasColumnName("status");
+
+                    b.HasKey("Id")
+                        .HasName("pk_identity_instances");
+
+                    b.HasIndex("Domain")
+                        .IsUnique()
+                        .HasDatabaseName("ix_identity_instances_domain");
+
+                    b.ToTable("identity_instances", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<Guid>("AuthorId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("author_id");
+
+                    b.Property<Guid>("ChannelId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("channel_id");
+
+                    b.Property<string>("Content")
+                        .HasColumnType("text")
+                        .HasColumnName("content");
+
+                    b.Property<Instant?>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("updated_at");
+
+                    b.HasKey("Id")
+                        .HasName("pk_messages");
+
+                    b.HasIndex("AuthorId")
+                        .HasDatabaseName("ix_messages_author_id");
+
+                    b.HasIndex("ChannelId")
+                        .HasDatabaseName("ix_messages_channel_id");
+
+                    b.ToTable("messages", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .HasColumnType("uuid")
+                        .HasColumnName("id");
+
+                    b.Property<string>("Avatar")
+                        .HasColumnType("text")
+                        .HasColumnName("avatar");
+
+                    b.Property<Guid>("InstanceId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("instance_id");
+
+                    b.Property<Instant>("LastFetchedAt")
+                        .HasColumnType("timestamp with time zone")
+                        .HasColumnName("last_fetched_at");
+
+                    b.Property<string>("RemoteUserId")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("remote_user_id");
+
+                    b.Property<string>("Username")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("username");
+
+                    b.HasKey("Id")
+                        .HasName("pk_users");
+
+                    b.HasIndex("InstanceId")
+                        .HasDatabaseName("ix_users_instance_id");
+
+                    b.HasIndex("RemoteUserId", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_remote_user_id_instance_id");
+
+                    b.HasIndex("Username", "InstanceId")
+                        .IsUnique()
+                        .HasDatabaseName("ix_users_username_instance_id");
+
+                    b.ToTable("users", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Core.Database.Instance", b =>
+                {
+                    b.Property<int>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("integer")
+                        .HasColumnName("id");
+
+                    NpgsqlPropertyBuilderExtensions.UseIdentityByDefaultColumn(b.Property<int>("Id"));
+
+                    b.Property<string>("PrivateKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("private_key");
+
+                    b.Property<string>("PublicKey")
+                        .IsRequired()
+                        .HasColumnType("text")
+                        .HasColumnName("public_key");
+
+                    b.HasKey("Id")
+                        .HasName("pk_instance");
+
+                    b.ToTable("instance", (string)null);
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.Property<Guid>("GuildsId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("guilds_id");
+
+                    b.Property<Guid>("UsersId")
+                        .HasColumnType("uuid")
+                        .HasColumnName("users_id");
+
+                    b.HasKey("GuildsId", "UsersId")
+                        .HasName("pk_guild_user");
+
+                    b.HasIndex("UsersId")
+                        .HasDatabaseName("ix_guild_user_users_id");
+
+                    b.ToTable("guild_user", (string)null);
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Channel", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", "Guild")
+                        .WithMany("Channels")
+                        .HasForeignKey("GuildId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_channels_guilds_guild_id");
+
+                    b.Navigation("Guild");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Owner")
+                        .WithMany("OwnedGuilds")
+                        .HasForeignKey("OwnerId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guilds_users_owner_id");
+
+                    b.Navigation("Owner");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Message", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.User", "Author")
+                        .WithMany()
+                        .HasForeignKey("AuthorId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_users_author_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.Channel", "Channel")
+                        .WithMany()
+                        .HasForeignKey("ChannelId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_messages_channels_channel_id");
+
+                    b.Navigation("Author");
+
+                    b.Navigation("Channel");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.IdentityInstance", "Instance")
+                        .WithMany()
+                        .HasForeignKey("InstanceId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_users_identity_instances_instance_id");
+
+                    b.Navigation("Instance");
+                });
+
+            modelBuilder.Entity("GuildUser", b =>
+                {
+                    b.HasOne("Foxchat.Chat.Database.Models.Guild", null)
+                        .WithMany()
+                        .HasForeignKey("GuildsId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_guilds_guilds_id");
+
+                    b.HasOne("Foxchat.Chat.Database.Models.User", null)
+                        .WithMany()
+                        .HasForeignKey("UsersId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired()
+                        .HasConstraintName("fk_guild_user_users_users_id");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.Guild", b =>
+                {
+                    b.Navigation("Channels");
+                });
+
+            modelBuilder.Entity("Foxchat.Chat.Database.Models.User", b =>
+                {
+                    b.Navigation("OwnedGuilds");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

Foxchat.Chat/Program.cs

@@ -3,16 +3,28 @@ using Serilog;
 using Foxchat.Core;
 using Foxchat.Chat;
 using Foxchat.Chat.Database;
+using Foxchat.Chat.Extensions;
+using Foxchat.Core.Extensions;
+using Newtonsoft.Json;
 
 var builder = WebApplication.CreateBuilder(args);
 
 var config = builder.AddConfiguration<InstanceConfig>("chat.ini");
 
-builder.AddSerilog(config.LogEventLevel);
+builder.AddSerilog();
 
 await BuildInfo.ReadBuildInfo();
 Log.Information("Starting Foxchat.Chat {Version} ({Hash})", BuildInfo.Version, BuildInfo.Hash);
 
+// Set the default converter to snake case as we use it in a couple places.
+JsonConvert.DefaultSettings = () => new JsonSerializerSettings
+{
+    ContractResolver = new DefaultContractResolver
+    {
+        NamingStrategy = new SnakeCaseNamingStrategy()
+    }
+};
+
 builder.Services
     .AddControllers()
     .AddNewtonsoftJson(options =>
@@ -23,6 +35,8 @@ builder.Services
 
 builder.Services
     .AddCoreServices<ChatContext>()
+    .AddChatServices()
+    .AddCustomMiddleware()
     .AddEndpointsApiExplorer()
     .AddSwaggerGen();
 
@@ -33,12 +47,11 @@ app.UseRouting();
 app.UseSwagger();
 app.UseSwaggerUI();
 app.UseCors();
-app.UseAuthentication();
-app.UseAuthorization();
+app.UseCustomMiddleware();
 app.MapControllers();
 
 using (var scope = app.Services.CreateScope())
-using (var context = scope.ServiceProvider.GetRequiredService<ChatContext>())
+await using (var context = scope.ServiceProvider.GetRequiredService<ChatContext>())
 {
     Log.Information("Initializing instance keypair...");
     if (await context.InitializeInstanceAsync())

Foxchat.Chat/Services/UserResolverService.cs

@@ -0,0 +1,35 @@
+using Foxchat.Chat.Database;
+using Foxchat.Chat.Database.Models;
+using Foxchat.Core.Federation;
+using Foxchat.Core.Models;
+using Microsoft.EntityFrameworkCore;
+
+namespace Foxchat.Chat.Services;
+
+public class UserResolverService(ILogger logger, ChatContext db, RequestSigningService requestSigningService)
+{
+    public async Task<User> ResolveUserAsync(IdentityInstance instance, string userId)
+    {
+        var user = await db.Users.FirstOrDefaultAsync(u => u.InstanceId == instance.Id && u.RemoteUserId == userId);
+        if (user != null)
+        {
+            // TODO: update user if it's been long enough
+            return user;
+        }
+
+        var userResponse = await requestSigningService.RequestAsync<Users.User>(HttpMethod.Get, instance.Domain,
+            $"/_fox/ident/users/{userId}");
+
+        user = new User
+        {
+            Instance = instance,
+            Username = userResponse.Username,
+            RemoteUserId = userResponse.Id,
+            Avatar = userResponse.AvatarUrl
+        };
+
+        db.Add(user);
+        await db.SaveChangesAsync();
+        return user;
+    }
+}

Foxchat.Chat/chat.ini

@@ -2,9 +2,6 @@ Host = localhost
 Port = 7610
 Domain = chat.fox.localhost
 
-; The level to log things at. Valid settings: Verbose, Debug, Information, Warning, Error, Fatal
-LogEventLevel = Debug
-
 [Database]
 ; The database URL in ADO.NET format.
 Url = "Host=localhost;Database=foxchat_cs_chat;Username=foxchat;Password=password"
@@ -13,3 +10,11 @@ Url = "Host=localhost;Database=foxchat_cs_chat;Username=foxchat;Password=passwor
 Timeout = 5
 ; The maximum number of open connections. Defaults to 50.
 MaxPoolSize = 500
+
+[Logging]
+; The level to log things at. Valid settings: Verbose, Debug, Information, Warning, Error, Fatal
+LogEventLevel = Debug
+; Whether to log SQL queries.
+LogQueries = true
+; Optional logging to Seq
+SeqLogUrl = http://localhost:5341

Foxchat.Core/CoreConfig.cs

@@ -11,9 +11,7 @@ public class CoreConfig
 
     public string Address => $"{(Secure ? "https" : "http")}://{Host}:{Port}";
 
-    public LogEventLevel LogEventLevel { get; set; } = LogEventLevel.Debug;
-    public string? SeqLogUrl { get; set; }
-
+    public LoggingConfig Logging { get; set; } = new();
     public DatabaseConfig Database { get; set; } = new();
 
     public class DatabaseConfig
@@ -22,4 +20,11 @@ public class CoreConfig
         public int? Timeout { get; set; }
         public int? MaxPoolSize { get; set; }
     }
-}
+
+    public class LoggingConfig
+    {
+        public LogEventLevel LogEventLevel { get; set; } = LogEventLevel.Debug;
+        public string? SeqLogUrl { get; set; }
+        public bool LogQueries { get; set; } = false;
+    }
+}

Foxchat.Core/Database/IDatabaseContext.cs

@@ -16,11 +16,11 @@ public abstract class IDatabaseContext : DbContext
         var publicKey = rsa.ExportRSAPublicKeyPem();
         var privateKey = rsa.ExportRSAPrivateKeyPem();
 
-        await Instance.AddAsync(new Instance
+        Instance.Add(new Instance
         {
             PublicKey = publicKey!,
             PrivateKey = privateKey!,
-        }, ct);
+        });
 
         await SaveChangesAsync(ct);
         return true;

Foxchat.Core/Extensions/HttpContextExtensions.cs

@@ -0,0 +1,40 @@
+using System.Diagnostics.CodeAnalysis;
+using Foxchat.Core.Federation;
+using Microsoft.AspNetCore.Http;
+
+namespace Foxchat.Core.Extensions;
+
+public static class HttpContextExtensions
+{
+    public static bool ExtractRequestData(this HttpContext ctx, [NotNullWhen(true)] out string? signature,
+        [NotNullWhen(true)] out string? domain, [NotNullWhen(true)] out SignatureData? data)
+    {
+        signature = null;
+        domain = null;
+        data = null;
+
+        if (!ctx.Request.Headers.TryGetValue(RequestSigningService.SIGNATURE_HEADER, out var encodedSignature))
+            return false;
+        if (!ctx.Request.Headers.TryGetValue(RequestSigningService.DATE_HEADER, out var date))
+            return false;
+        if (!ctx.Request.Headers.TryGetValue(RequestSigningService.SERVER_HEADER, out var server))
+            return false;
+        var time = RequestSigningService.ParseTime(date.ToString());
+        string? userId = null;
+        if (ctx.Request.Headers.TryGetValue(RequestSigningService.USER_HEADER, out var userIdHeader))
+            userId = userIdHeader;
+        var host = ctx.Request.Headers.Host.ToString();
+
+        signature = encodedSignature.ToString();
+        domain = server.ToString();
+        data = new SignatureData(
+            time,
+            host,
+            ctx.Request.Path,
+            (int?)ctx.Request.Headers.ContentLength,
+            userId
+        );
+
+        return true;
+    }
+}

Foxchat.Core/Extensions/ServiceCollectionExtensions.cs

@@ -7,30 +7,32 @@ using NodaTime;
 using Serilog;
 using Serilog.Events;
 
-namespace Foxchat.Core;
+namespace Foxchat.Core.Extensions;
 
 public static class ServiceCollectionExtensions
 {
     /// <summary>
     /// Adds Serilog to this service collection. This method also initializes Serilog so it should be called as early as possible, before any log calls.
     /// </summary>
-    public static void AddSerilog(this WebApplicationBuilder builder, LogEventLevel level)
+    public static void AddSerilog(this WebApplicationBuilder builder)
     {
         var config = builder.Configuration.Get<CoreConfig>() ?? new();
 
         var logCfg = new LoggerConfiguration()
             .Enrich.FromLogContext()
-            .MinimumLevel.Is(level)
+            .MinimumLevel.Is(config.Logging.LogEventLevel)
             // ASP.NET's built in request logs are extremely verbose, so we use Serilog's instead.
-            // Serilog doesn't disable the built in logs so we do it here.
+            // Serilog doesn't disable the built-in logs, so we do it here.
             .MinimumLevel.Override("Microsoft", LogEventLevel.Information)
+            .MinimumLevel.Override("Microsoft.EntityFrameworkCore.Database.Command",
+                config.Logging.LogQueries ? LogEventLevel.Information : LogEventLevel.Warning)
             .MinimumLevel.Override("Microsoft.AspNetCore.Hosting", LogEventLevel.Warning)
             .MinimumLevel.Override("Microsoft.AspNetCore.Mvc", LogEventLevel.Warning)
             .MinimumLevel.Override("Microsoft.AspNetCore.Routing", LogEventLevel.Warning)
             .WriteTo.Console();
 
-        if (config.SeqLogUrl != null)
-            logCfg.WriteTo.Seq(config.SeqLogUrl, restrictedToMinimumLevel: LogEventLevel.Verbose);
+        if (config.Logging.SeqLogUrl != null)
+            logCfg.WriteTo.Seq(config.Logging.SeqLogUrl, restrictedToMinimumLevel: LogEventLevel.Verbose);
 
         Log.Logger = logCfg.CreateLogger();
 
@@ -54,9 +56,9 @@ public static class ServiceCollectionExtensions
         return services;
     }
 
-    public static T AddConfiguration<T>(this WebApplicationBuilder builder, string? configFile = null) where T : class, new()
+    public static T AddConfiguration<T>(this WebApplicationBuilder builder, string? configFile = null)
+        where T : class, new()
     {
-
         builder.Configuration.Sources.Clear();
         builder.Configuration.AddConfiguration(configFile);
 
@@ -76,4 +78,4 @@ public static class ServiceCollectionExtensions
             .AddIniFile(file, optional: false, reloadOnChange: true)
             .AddEnvironmentVariables();
     }
-}
+}

Foxchat.Core/Federation/RequestSigningService.Client.cs

@@ -1,5 +1,4 @@
 using System.Net.Http.Headers;
-using Foxchat.Core.Models;
 using Newtonsoft.Json;
 using Newtonsoft.Json.Serialization;
 
@@ -15,14 +14,6 @@ public partial class RequestSigningService
     public const string SIGNATURE_HEADER = "X-Foxchat-Signature";
     public const string USER_HEADER = "X-Foxchat-User";
 
-    private static readonly JsonSerializerSettings _jsonSerializerSettings = new()
-    {
-        ContractResolver = new DefaultContractResolver
-        {
-            NamingStrategy = new SnakeCaseNamingStrategy()
-        }
-    };
-
     public async Task<T> RequestAsync<T>(HttpMethod method, string domain, string requestPath, string? userId = null, object? body = null)
     {
         var request = BuildHttpRequest(method, domain, requestPath, userId, body);
@@ -30,17 +21,17 @@ public partial class RequestSigningService
         if (!resp.IsSuccessStatusCode)
         {
             var error = await resp.Content.ReadAsStringAsync();
-            throw new ApiError.OutgoingFederationError($"Request to {domain}{requestPath} returned an error", DeserializeObject<Models.ApiError>(error));
+            throw new ApiError.OutgoingFederationError($"Request to {domain}{requestPath} returned an error", JsonConvert.DeserializeObject<Models.Http.ApiError>(error));
         }
 
         var bodyString = await resp.Content.ReadAsStringAsync();
-        return DeserializeObject<T>(bodyString)
+        return JsonConvert.DeserializeObject<T>(bodyString)
             ?? throw new ApiError.OutgoingFederationError($"Request to {domain}{requestPath} returned invalid response body");
     }
 
     private HttpRequestMessage BuildHttpRequest(HttpMethod method, string domain, string requestPath, string? userId = null, object? bodyData = null)
     {
-        var body = bodyData != null ? SerializeObject(bodyData) : null;
+        var body = bodyData != null ? JsonConvert.SerializeObject(bodyData) : null;
 
         var now = _clock.GetCurrentInstant();
         var url = $"https://{domain}{requestPath}";
@@ -59,7 +50,4 @@ public partial class RequestSigningService
 
         return request;
     }
-
-    public static string SerializeObject(object data) => JsonConvert.SerializeObject(data, _jsonSerializerSettings);
-    public static T? DeserializeObject<T>(string data) => JsonConvert.DeserializeObject<T>(data, _jsonSerializerSettings);
 }

Foxchat.Core/Federation/RequestSigningService.cs

@@ -31,23 +31,21 @@ public partial class RequestSigningService(ILogger logger, IClock clock, IDataba
     }
 
     public bool VerifySignature(
-        string publicKey, string encodedSignature, string dateHeader, string host, string requestPath, int? contentLength, string? userId)
+        string publicKey, string encodedSignature, SignatureData data)
     {
+        if (data.Host != _config.Domain)
+            throw new ApiError.IncomingFederationError("Request is not for this instance");
+
+        var now = _clock.GetCurrentInstant();
+        if (now + Duration.FromMinutes(1) < data.Time)
+            throw new ApiError.IncomingFederationError("Request was made in the future");
+        if (now - Duration.FromMinutes(1) > data.Time)
+            throw new ApiError.IncomingFederationError("Request was made too long ago");
+
         var rsa = RSA.Create();
         rsa.ImportFromPem(publicKey);
 
-        var now = _clock.GetCurrentInstant();
-        var time = ParseTime(dateHeader);
-        if ((now + Duration.FromMinutes(1)) < time)
-        {
-            throw new ApiError.IncomingFederationError("Request was made in the future");
-        }
-        else if ((now - Duration.FromMinutes(1)) > time)
-        {
-            throw new ApiError.IncomingFederationError("Request was made too long ago");
-        }
-
-        var plaintext = GeneratePlaintext(new SignatureData(time, host, requestPath, contentLength, userId));
+        var plaintext = GeneratePlaintext(data);
         var plaintextBytes = Encoding.UTF8.GetBytes(plaintext);
         var hash = SHA256.HashData(plaintextBytes);
 
@@ -71,7 +69,9 @@ public partial class RequestSigningService(ILogger logger, IClock clock, IDataba
         return $"{time}:{data.Host}:{data.RequestPath}:{contentLength}:{userId}";
     }
 
-    private static readonly InstantPattern _pattern = InstantPattern.Create("ddd, dd MMM yyyy HH:mm:ss 'GMT'", CultureInfo.GetCultureInfo("en-US"));
+    private static readonly InstantPattern _pattern =
+        InstantPattern.Create("ddd, dd MMM yyyy HH:mm:ss 'GMT'", CultureInfo.GetCultureInfo("en-US"));
+
     private static string FormatTime(Instant time) => _pattern.Format(time);
-    private static Instant ParseTime(string header) => _pattern.Parse(header).GetValueOrThrow();
-}
+    public static Instant ParseTime(string header) => _pattern.Parse(header).GetValueOrThrow();
+}

Foxchat.Core/Federation/SignatureData.cs

@@ -8,4 +8,13 @@ public record SignatureData(
     string RequestPath,
     int? ContentLength,
     string? UserId
-);
+)
+{
+    public static readonly SignatureData Empty = new(
+        Instant.MinValue,
+        string.Empty,
+        string.Empty,
+        null,
+        null
+    );
+}

Foxchat.Core/FoxchatError.cs

@@ -2,31 +2,31 @@ using System.Net;
 
 namespace Foxchat.Core;
 
-public class FoxchatError(string message) : Exception(message)
+public class FoxchatError(string message, Exception? inner = null) : Exception(message)
 {
-    public class DatabaseError(string message) : FoxchatError(message);
-    public class UnknownEntityError(Type entityType) : FoxchatError($"Entity of type {entityType.Name} not found");
+    public Exception? Inner => inner;
+
+    public class DatabaseError(string message, Exception? inner = null) : FoxchatError(message, inner);
+    public class UnknownEntityError(Type entityType, Exception? inner = null) : FoxchatError($"Entity of type {entityType.Name} not found", inner);
 }
 
 public class ApiError(string message, HttpStatusCode? statusCode = null) : FoxchatError(message)
 {
     public readonly HttpStatusCode StatusCode = statusCode ?? HttpStatusCode.InternalServerError;
-
     public class Unauthorized(string message) : ApiError(message, statusCode: HttpStatusCode.Unauthorized);
-
     public class Forbidden(string message, IEnumerable<string>? scopes = null) : ApiError(message, statusCode: HttpStatusCode.Forbidden)
     {
         public readonly string[] Scopes = scopes?.ToArray() ?? [];
     }
-
     public class BadRequest(string message) : ApiError(message, statusCode: HttpStatusCode.BadRequest);
+    public class NotFound(string message) : ApiError(message, statusCode: HttpStatusCode.NotFound);
     public class IncomingFederationError(string message) : ApiError(message, statusCode: HttpStatusCode.BadRequest);
 
     public class OutgoingFederationError(
-        string message, Models.ApiError? innerError = null
+        string message, Models.Http.ApiError? innerError = null
     ) : ApiError(message, statusCode: HttpStatusCode.InternalServerError)
     {
-        public Models.ApiError? InnerError => innerError;
+        public Models.Http.ApiError? InnerError => innerError;
     }
 
     public class AuthenticationError(string message) : ApiError(message, statusCode: HttpStatusCode.BadRequest);

Foxchat.Core/Middleware/ErrorHandlerMiddleware.cs

@@ -0,0 +1,86 @@
+using System.Net;
+using Foxchat.Core.Models.Http;
+using Microsoft.AspNetCore.Http;
+using Newtonsoft.Json;
+using HttpApiError = Foxchat.Core.Models.Http.ApiError;
+
+namespace Foxchat.Core.Middleware;
+
+public class ErrorHandlerMiddleware(ILogger baseLogger) : IMiddleware
+{
+    public async Task InvokeAsync(HttpContext ctx, RequestDelegate next)
+    {
+        try
+        {
+            await next(ctx);
+        }
+        catch (Exception e)
+        {
+            var type = e.TargetSite?.DeclaringType ?? typeof(ErrorHandlerMiddleware);
+            var typeName = e.TargetSite?.DeclaringType?.FullName ?? "<unknown>";
+            var logger = baseLogger.ForContext(type);
+
+            if (ctx.Response.HasStarted)
+            {
+                logger.Error(e, "Error in {ClassName} ({Path}) after response started being sent", typeName,
+                    ctx.Request.Path);
+            }
+
+            if (e is ApiError ae)
+            {
+                ctx.Response.StatusCode = (int)ae.StatusCode;
+                ctx.Response.Headers.RequestId = ctx.TraceIdentifier;
+                ctx.Response.ContentType = "application/json; charset=utf-8";
+                if (ae is ApiError.OutgoingFederationError ofe)
+                {
+                    await ctx.Response.WriteAsync(JsonConvert.SerializeObject(new HttpApiError
+                    {
+                        Status = (int)ofe.StatusCode,
+                        Code = ErrorCode.OutgoingFederationError,
+                        Message = ofe.Message,
+                        OriginalError = ofe.InnerError
+                    }));
+                    return;
+                }
+                else if (ae is ApiError.Forbidden fe)
+                {
+                    await ctx.Response.WriteAsync(JsonConvert.SerializeObject(new HttpApiError
+                    {
+                        Status = (int)fe.StatusCode,
+                        Code = ErrorCode.Forbidden,
+                        Message = fe.Message,
+                        Scopes = fe.Scopes.Length > 0 ? fe.Scopes : null
+                    }));
+                    return;
+                }
+
+                await ctx.Response.WriteAsync(JsonConvert.SerializeObject(new HttpApiError
+                {
+                    Status = (int)ae.StatusCode,
+                    Code = ErrorCode.GenericApiError,
+                    Message = ae.Message,
+                }));
+                return;
+            }
+
+            if (e is FoxchatError fce)
+            {
+                logger.Error(fce.Inner ?? fce, "Exception in {ClassName} ({Path})", typeName, ctx.Request.Path);
+            }
+            else
+            {
+                logger.Error(e, "Exception in {ClassName} ({Path})", typeName, ctx.Request.Path);
+            }
+
+            ctx.Response.StatusCode = (int)HttpStatusCode.InternalServerError;
+            ctx.Response.Headers.RequestId = ctx.TraceIdentifier;
+            ctx.Response.ContentType = "application/json; charset=utf-8";
+            await ctx.Response.WriteAsync(JsonConvert.SerializeObject(new HttpApiError
+            {
+                Status = (int)HttpStatusCode.InternalServerError,
+                Code = ErrorCode.InternalServerError,
+                Message = "Internal server error",
+            }));
+        }
+    }
+}

Foxchat.Core/Models/ApiError.cs

@@ -1,17 +0,0 @@
-namespace Foxchat.Core.Models;
-
-public record ApiError(int Status, ErrorCode Code, string Message);
-
-public enum ErrorCode
-{
-    INTERNAL_SERVER_ERROR,
-    OBJECT_NOT_FOUND,
-    INVALID_SERVER,
-    INVALID_HEADER,
-    INVALID_DATE,
-    INVALID_SIGNATURE,
-    MISSING_SIGNATURE,
-    GUILD_NOT_FOUND,
-    UNAUTHORIZED,
-    INVALID_REST_EVENT,
-}

Foxchat.Core/Models/Channels.cs

@@ -0,0 +1,8 @@
+namespace Foxchat.Core.Models;
+
+public static class Channels
+{
+    public record Channel(string Id, string GuildId, string Name, string? Topic);
+
+    public record PartialChannel(string Id, string Name);
+}

Foxchat.Core/Models/Guilds.cs

@@ -0,0 +1,14 @@
+using Newtonsoft.Json;
+
+namespace Foxchat.Core.Models;
+
+public static class Guilds
+{
+    public record Guild(
+        string Id,
+        string Name,
+        IEnumerable<string> OwnerIds,
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        IEnumerable<Channels.PartialChannel>? Channels
+    );
+}

Foxchat.Core/Models/Http/ApiError.cs

@@ -0,0 +1,28 @@
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+
+namespace Foxchat.Core.Models.Http;
+
+public record ApiError
+{
+    public required int Status { get; init; }
+    [JsonConverter(typeof(StringEnumConverter))]
+    public required ErrorCode Code { get; init; }
+    public required string Message { get; init; }
+    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+    public ApiError? OriginalError { get; init; }
+    [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+    public string[]? Scopes { get; init; }
+}
+
+public enum ErrorCode
+{
+    InternalServerError,
+    Unauthorized,
+    Forbidden,
+    BadRequest,
+    OutgoingFederationError,
+    AuthenticationError,
+    // TODO: more specific API error codes
+    GenericApiError,
+}

Foxchat.Core/Models/Http/AppsApi.cs

@@ -1,6 +1,6 @@
 namespace Foxchat.Core.Models.Http;
 
-public static class Apps
+public static class AppsApi
 {
     public record CreateRequest(string Name, string[] Scopes, string[] RedirectUris);
     public record CreateResponse(Ulid Id, string ClientId, string ClientSecret, string Name, string[] Scopes, string[] RedirectUris);

Foxchat.Core/Models/Http/GuildsApi.cs

@@ -0,0 +1,6 @@
+namespace Foxchat.Core.Models.Http;
+
+public static class GuildsApi
+{
+    public record CreateGuildRequest(string Name);
+}

Foxchat.Core/Models/Http/Hello.cs

@@ -4,6 +4,6 @@ public static class Hello
 {
     public record HelloRequest(string Host);
     public record HelloResponse(string PublicKey, string Host);
-    public record NodeInfo(string Software, string PublicKey);
+    public record NodeInfo(NodeSoftware Software, string PublicKey);
     public record NodeSoftware(string Name, string? Version);
 }

Foxchat.Core/Models/Users.cs

@@ -0,0 +1,8 @@
+namespace Foxchat.Core.Models;
+
+public static class Users
+{
+    public record User(string Id, string Username, string Instance, string? AvatarUrl);
+
+    public record PartialUser(string Id, string Username, string Instance);
+}

Foxchat.Identity/Controllers/NodeController.cs

@@ -1,3 +1,4 @@
+using Foxchat.Core;
 using Foxchat.Core.Models.Http;
 using Foxchat.Identity.Database;
 using Foxchat.Identity.Services;
@@ -7,15 +8,16 @@ namespace Foxchat.Identity.Controllers;
 
 [ApiController]
 [Route("/_fox/ident/node")]
-public class NodeController(IdentityContext db, ChatInstanceResolverService chatInstanceResolverService) : ControllerBase
+public class NodeController(IdentityContext db, ChatInstanceResolverService chatInstanceResolverService)
+    : ControllerBase
 {
-    public const string SOFTWARE_NAME = "Foxchat.NET.Identity";
+    private const string SoftwareName = "Foxchat.NET.Identity";
 
     [HttpGet]
     public async Task<IActionResult> GetNode()
     {
         var instance = await db.GetInstanceAsync();
-        return Ok(new Hello.NodeInfo(SOFTWARE_NAME, instance.PublicKey));
+        return Ok(new Hello.NodeInfo(new Hello.NodeSoftware(SoftwareName, BuildInfo.Version), instance.PublicKey));
     }
 
     [HttpGet("{domain}")]
@@ -24,4 +26,4 @@ public class NodeController(IdentityContext db, ChatInstanceResolverService chat
         var instance = await chatInstanceResolverService.ResolveChatInstanceAsync(domain);
         return Ok(instance);
     }
-}
+}

Foxchat.Identity/Controllers/Oauth/AppsController.cs

@@ -1,27 +1,28 @@
 using Foxchat.Core;
 using Foxchat.Core.Models.Http;
-using Foxchat.Identity.Authorization;
+using Foxchat.Identity.Middleware;
 using Foxchat.Identity.Database;
 using Foxchat.Identity.Database.Models;
+using Foxchat.Identity.Utils;
 using Microsoft.AspNetCore.Mvc;
 
 namespace Foxchat.Identity.Controllers.Oauth;
 
 [ApiController]
-[Authenticate]
+[ClientAuthenticate]
 [Route("/_fox/ident/oauth/apps")]
 public class AppsController(ILogger logger, IdentityContext db) : ControllerBase
 {
     [HttpPost]
-    public async Task<IActionResult> CreateApplication([FromBody] Apps.CreateRequest req)
+    public async Task<IActionResult> CreateApplication([FromBody] AppsApi.CreateRequest req)
     {
         var app = Application.Create(req.Name, req.Scopes, req.RedirectUris);
-        await db.AddAsync(app);
+        db.Add(app);
         await db.SaveChangesAsync();
 
         logger.Information("Created new application {Name} with ID {Id} and client ID {ClientId}", app.Name, app.Id, app.ClientId);
 
-        return Ok(new Apps.CreateResponse(
+        return Ok(new AppsApi.CreateResponse(
             app.Id, app.ClientId, app.ClientSecret, app.Name, app.Scopes, app.RedirectUris
         ));
     }
@@ -29,11 +30,9 @@ public class AppsController(ILogger logger, IdentityContext db) : ControllerBase
     [HttpGet]
     public IActionResult GetSelfApp([FromQuery(Name = "with_secret")] bool withSecret)
     {
-        var token = HttpContext.GetToken();
-        if (token is not { Account: null }) throw new ApiError.Forbidden("This endpoint requires a client token.");
-        var app = token.Application;
+        var app = HttpContext.GetApplicationOrThrow();
 
-        return Ok(new Apps.GetSelfResponse(
+        return Ok(new AppsApi.GetSelfResponse(
             app.Id,
             app.ClientId,
             withSecret ? app.ClientSecret : null,

Foxchat.Identity/Controllers/Oauth/PasswordAuthController.cs

@@ -0,0 +1,84 @@
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Database;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.AspNetCore.Identity;
+using Foxchat.Identity.Database.Models;
+using Foxchat.Core;
+using System.Diagnostics;
+using Foxchat.Identity.Utils;
+using NodaTime;
+using Microsoft.EntityFrameworkCore;
+
+namespace Foxchat.Identity.Controllers.Oauth;
+
+[ApiController]
+[ClientAuthenticate]
+[Route("/_fox/ident/oauth/password")]
+public class PasswordAuthController(ILogger logger, IdentityContext db, IClock clock) : ControllerBase
+{
+    private readonly PasswordHasher<Account> _passwordHasher = new();
+
+    [HttpPost("register")]
+    public async Task<IActionResult> Register([FromBody] RegisterRequest req)
+    {
+        var app = HttpContext.GetApplicationOrThrow();
+        var appToken =
+            HttpContext.GetToken() ??
+            throw new UnreachableException(); // GetApplicationOrThrow already gets the token and throws if it's null
+        var appScopes = appToken.Scopes.ExpandScopes();
+
+        if (req.Scopes.Except(appScopes).Any())
+            throw new ApiError.Forbidden("Cannot request token scopes that are not allowed for this token",
+                req.Scopes.Except(appScopes));
+
+        var acct = new Account
+        {
+            Username = req.Username,
+            Email = req.Email,
+            Role = Account.AccountRole.User
+        };
+
+        db.Add(acct);
+        var hashedPassword = await Task.Run(() => _passwordHasher.HashPassword(acct, req.Password));
+        acct.Password = hashedPassword;
+        // TODO: make token expiry configurable
+        var (tokenStr, token) = Token.Create(acct, app, req.Scopes, clock.GetCurrentInstant() + Duration.FromDays(365));
+        db.Add(token);
+        await db.SaveChangesAsync();
+
+        return Ok(new AuthResponse(acct.Id, acct.Username, acct.Email, tokenStr));
+    }
+
+    [HttpPost("login")]
+    public async Task<IActionResult> Login([FromBody] LoginRequest req)
+    {
+        var app = HttpContext.GetApplicationOrThrow();
+        var appToken = HttpContext.GetToken() ?? throw new UnreachableException();
+        var appScopes = appToken.Scopes.ExpandScopes();
+
+        if (req.Scopes.Except(appScopes).Any())
+            throw new ApiError.Forbidden("Cannot request token scopes that are not allowed for this token",
+                req.Scopes.Except(appScopes));
+
+        var acct = await db.Accounts.FirstOrDefaultAsync(a => a.Email == req.Email)
+                   ?? throw new ApiError.NotFound("No user with that email found, or password is incorrect");
+
+        var pwResult = await Task.Run(() => _passwordHasher.VerifyHashedPassword(acct, acct.Password, req.Password));
+        if (pwResult == PasswordVerificationResult.Failed)
+            throw new ApiError.NotFound("No user with that email found, or password is incorrect");
+        if (pwResult == PasswordVerificationResult.SuccessRehashNeeded)
+            acct.Password = await Task.Run(() => _passwordHasher.HashPassword(acct, req.Password));
+
+        var (tokenStr, token) = Token.Create(acct, app, req.Scopes, clock.GetCurrentInstant() + Duration.FromDays(365));
+        db.Add(token);
+        await db.SaveChangesAsync();
+
+        return Ok(new AuthResponse(acct.Id, acct.Username, acct.Email, tokenStr));
+    }
+
+    public record RegisterRequest(string Username, string Password, string Email, string[] Scopes);
+
+    public record LoginRequest(string Email, string Password, string[] Scopes);
+
+    public record AuthResponse(Ulid Id, string Username, string Email, string Token);
+}

Foxchat.Identity/Controllers/Oauth/TokenController.cs

@@ -1,6 +1,7 @@
 using Foxchat.Core;
 using Foxchat.Identity.Database;
 using Foxchat.Identity.Database.Models;
+using Foxchat.Identity.Utils;
 using Microsoft.AspNetCore.Mvc;
 using NodaTime;
 
@@ -14,18 +15,20 @@ public class TokenController(ILogger logger, IdentityContext db, IClock clock) :
     public async Task<IActionResult> PostToken([FromBody] PostTokenRequest req)
     {
         var app = await db.GetApplicationAsync(req.ClientId, req.ClientSecret);
+        var appScopes = app.Scopes.ExpandScopes();
 
         var scopes = req.Scope.Split(' ');
-        if (app.Scopes.Except(scopes).Any())
+        if (scopes.Except(appScopes).Any())
         {
-            throw new ApiError.BadRequest("Invalid or unauthorized scopes");
+            throw new ApiError.Forbidden("Invalid or unauthorized scopes", scopes.Except(appScopes));
         }
 
         switch (req.GrantType)
         {
-            case "client_credentials":
+            case OauthUtils.ClientCredentials:
                 return await HandleClientCredentialsAsync(app, scopes);
-            case "authorization_code":
+            case OauthUtils.AuthorizationCode:
+                // TODO
                 break;
             default:
                 throw new ApiError.BadRequest("Unknown grant_type");
@@ -38,16 +41,9 @@ public class TokenController(ILogger logger, IdentityContext db, IClock clock) :
     {
         // TODO: make this configurable
         var expiry = clock.GetCurrentInstant() + Duration.FromDays(365);
-        var (token, hash) = Token.Generate();
-        var tokenObj = new Token
-        {
-            Hash = hash,
-            Scopes = scopes,
-            Expires = expiry,
-            ApplicationId = app.Id
-        };
+        var (token, tokenObj) = Token.Create(null, app, scopes, expiry);
 
-        await db.AddAsync(tokenObj);
+        db.Add(tokenObj);
         await db.SaveChangesAsync();
 
         logger.Debug("Created token with scopes {Scopes} for application {ApplicationId}", scopes, app.Id);

Foxchat.Identity/Controllers/Proxy/GuildsProxyController.cs

@@ -0,0 +1,21 @@
+using Foxchat.Core.Federation;
+using Foxchat.Core.Models;
+using Foxchat.Core.Models.Http;
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Services;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Foxchat.Identity.Controllers.Proxy;
+
+[Route("/_fox/proxy/guilds")]
+public class GuildsProxyController(
+    ILogger logger,
+    ChatInstanceResolverService chatInstanceResolverService,
+    RequestSigningService requestSigningService)
+    : ProxyControllerBase(logger, chatInstanceResolverService, requestSigningService)
+{
+    [Authorize("chat_client")]
+    [HttpPost]
+    public Task<IActionResult> CreateGuild([FromBody] GuildsApi.CreateGuildRequest req) =>
+        Proxy<Guilds.Guild>(HttpMethod.Post, req);
+}

Foxchat.Identity/Controllers/Proxy/ProxyControllerBase.cs

@@ -0,0 +1,38 @@
+using Foxchat.Core;
+using Foxchat.Core.Federation;
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Services;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Foxchat.Identity.Controllers.Proxy;
+
+[ApiController]
+[ClientAuthenticate]
+public class ProxyControllerBase(
+    ILogger logger,
+    ChatInstanceResolverService chatInstanceResolverService,
+    RequestSigningService requestSigningService) : ControllerBase
+{
+    internal async Task<IActionResult> Proxy<TResponse>(HttpMethod method, object? body = null) where TResponse : class
+    {
+        var acct = HttpContext.GetAccountOrThrow();
+
+        var path = HttpContext.Request.Path.ToString();
+        if (!path.StartsWith("/_fox/proxy"))
+            throw new FoxchatError("Proxy<T> used for endpoint that does not start with /_fox/proxy");
+        path = $"/_fox/chat/{path[12..]}";
+
+        if (!HttpContext.Request.Headers.TryGetValue(RequestSigningService.SERVER_HEADER, out var serverHeader))
+            throw new ApiError.BadRequest($"Invalid or missing {RequestSigningService.SERVER_HEADER} header.");
+        var server = serverHeader.ToString();
+
+        logger.Debug("Proxying {Method} request to {Domain}{Path}", method, server, path);
+
+        // Identity instances always initiate federation, so we have to make sure the instance knows about us.
+        // This also serves as a way to make sure the instance being requested actually exists.
+        await chatInstanceResolverService.ResolveChatInstanceAsync(serverHeader.ToString());
+
+        var resp = await requestSigningService.RequestAsync<TResponse>(method, server, path, acct.Id.ToString(), body);
+        return Ok(resp);
+    }
+}

Foxchat.Identity/Controllers/UsersController.cs

@@ -0,0 +1,52 @@
+using Foxchat.Core;
+using Foxchat.Core.Models;
+using Foxchat.Identity.Database;
+using Foxchat.Identity.Database.Models;
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Utils;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using Newtonsoft.Json;
+
+namespace Foxchat.Identity.Controllers;
+
+[ApiController]
+[ClientAuthenticate]
+[Route("/_fox/ident/users")]
+public class UsersController(ILogger logger, InstanceConfig config, IdentityContext db) : ControllerBase
+{
+    [HttpGet("{id}")]
+    public async Task<IActionResult> GetUser(Ulid id)
+    {
+        var user = await db.Accounts.FirstOrDefaultAsync(a => a.Id == id);
+        if (user == null) throw new ApiError.NotFound("User not found.");
+
+        return Ok(new Users.User(user.Id.ToString(), user.Username, config.Domain, null));
+    }
+
+    [HttpGet("@me")]
+    [Authorize("identify")]
+    public IActionResult GetMe()
+    {
+        var acct = HttpContext.GetAccountOrThrow();
+        var token = HttpContext.GetToken()!;
+        var showEmail = token.Scopes.ExpandScopes().Contains("email");
+
+        return Ok(new MeUser(
+            acct.Id,
+            acct.Username,
+            acct.Role,
+            null,
+            showEmail ? acct.Email : null
+        ));
+    }
+
+    public record MeUser(
+        Ulid Id,
+        string Username,
+        Account.AccountRole Role,
+        string? AvatarUrl,
+        [JsonProperty(NullValueHandling = NullValueHandling.Ignore)]
+        string? Email
+    );
+}

Foxchat.Identity/Database/IdentityContext.cs

@@ -1,5 +1,6 @@
 using Foxchat.Core;
 using Foxchat.Core.Database;
+using Foxchat.Core.Extensions;
 using Foxchat.Identity.Database.Models;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Design;
@@ -10,15 +11,16 @@ namespace Foxchat.Identity.Database;
 public class IdentityContext : IDatabaseContext
 {
     private readonly NpgsqlDataSource _dataSource;
+    private readonly ILoggerFactory? _loggerFactory;
 
+    public override DbSet<Instance> Instance { get; set; }
     public DbSet<Account> Accounts { get; set; }
     public DbSet<ChatInstance> ChatInstances { get; set; }
-    public override DbSet<Instance> Instance { get; set; }
     public DbSet<Application> Applications { get; set; }
     public DbSet<Token> Tokens { get; set; }
     public DbSet<GuildAccount> GuildAccounts { get; set; }
 
-    public IdentityContext(InstanceConfig config)
+    public IdentityContext(InstanceConfig config, ILoggerFactory? loggerFactory)
     {
         var connString = new NpgsqlConnectionStringBuilder(config.Database.Url)
         {
@@ -29,12 +31,14 @@ public class IdentityContext : IDatabaseContext
         var dataSourceBuilder = new NpgsqlDataSourceBuilder(connString);
         dataSourceBuilder.UseNodaTime();
         _dataSource = dataSourceBuilder.Build();
+        _loggerFactory = loggerFactory;
     }
 
     protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
-            => optionsBuilder
-                .UseNpgsql(_dataSource, o => o.UseNodaTime())
-                .UseSnakeCaseNamingConvention();
+        => optionsBuilder
+            .UseNpgsql(_dataSource, o => o.UseNodaTime())
+            .UseSnakeCaseNamingConvention()
+            .UseLoggerFactory(_loggerFactory);
 
     protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
     {
@@ -55,6 +59,7 @@ public class IdentityContext : IDatabaseContext
     }
 }
 
+// ReSharper disable once UnusedType.Global
 public class DesignTimeIdentityContextFactory : IDesignTimeDbContextFactory<IdentityContext>
 {
     public IdentityContext CreateDbContext(string[] args)
@@ -66,6 +71,6 @@ public class DesignTimeIdentityContextFactory : IDesignTimeDbContextFactory<Iden
             // Get the configuration as our config class
             .Get<InstanceConfig>() ?? new();
 
-        return new IdentityContext(config);
+        return new IdentityContext(config, null);
     }
 }

Foxchat.Identity/Database/Models/Token.cs

@@ -24,4 +24,17 @@ public class Token : BaseModel
 
         return (token, hash);
     }
+
+    public static (string, Token) Create(Account? account, Application application, string[] scopes, Instant expires)
+    {
+        var (token, hash) = Generate();
+        return (token, new()
+        {
+            Hash = hash,
+            Scopes = scopes,
+            Expires = expires,
+            Account = account,
+            Application = application,
+        });
+    }
 }

Foxchat.Identity/Extensions/WebApplicationExtensions.cs

@@ -1,4 +1,5 @@
-using Foxchat.Identity.Authorization;
+using Foxchat.Core.Middleware;
+using Foxchat.Identity.Middleware;
 
 namespace Foxchat.Identity.Extensions;
 
@@ -7,14 +8,16 @@ public static class WebApplicationExtensions
     public static IServiceCollection AddCustomMiddleware(this IServiceCollection services)
     {
         return services
-            .AddScoped<AuthenticationMiddleware>()
-            .AddScoped<AuthorizationMiddleware>();
+            .AddScoped<ErrorHandlerMiddleware>()
+            .AddScoped<ClientAuthenticationMiddleware>()
+            .AddScoped<ClientAuthorizationMiddleware>();
     }
 
     public static IApplicationBuilder UseCustomMiddleware(this IApplicationBuilder app)
     {
         return app
-            .UseMiddleware<AuthenticationMiddleware>()
-            .UseMiddleware<AuthorizationMiddleware>();
+            .UseMiddleware<ErrorHandlerMiddleware>()
+            .UseMiddleware<ClientAuthenticationMiddleware>()
+            .UseMiddleware<ClientAuthorizationMiddleware>();
     }
 }

Foxchat.Identity/Middleware/ClientAuthenticationMiddleware.cs

@@ -6,9 +6,9 @@ using Foxchat.Identity.Database.Models;
 using Microsoft.EntityFrameworkCore;
 using NodaTime;
 
-namespace Foxchat.Identity.Authorization;
+namespace Foxchat.Identity.Middleware;
 
-public class AuthenticationMiddleware(
+public class ClientAuthenticationMiddleware(
     IdentityContext db,
     IClock clock
 ) : IMiddleware
@@ -16,7 +16,7 @@ public class AuthenticationMiddleware(
     public async Task InvokeAsync(HttpContext ctx, RequestDelegate next)
     {
         var endpoint = ctx.GetEndpoint();
-        var metadata = endpoint?.Metadata.GetMetadata<AuthenticateAttribute>();
+        var metadata = endpoint?.Metadata.GetMetadata<ClientAuthenticateAttribute>();
 
         if (metadata == null)
         {
@@ -71,7 +71,14 @@ public static class HttpContextExtensions
             return token as Token;
         return null;
     }
+
+    public static Application GetApplicationOrThrow(this HttpContext context)
+    {
+        var token = context.GetToken();
+        if (token is not { Account: null }) throw new ApiError.Forbidden("This endpoint requires a client token.");
+        return token.Application;
+    }
 }
 
 [AttributeUsage(AttributeTargets.Class | AttributeTargets.Method)]
-public class AuthenticateAttribute : Attribute;
+public class ClientAuthenticateAttribute : Attribute;

Foxchat.Identity/Middleware/ClientAuthorizationMiddleware.cs

@@ -1,11 +1,11 @@
-using System.Net;
 using Foxchat.Core;
 using Foxchat.Identity.Database;
+using Foxchat.Identity.Utils;
 using NodaTime;
 
-namespace Foxchat.Identity.Authorization;
+namespace Foxchat.Identity.Middleware;
 
-public class AuthorizationMiddleware(
+public class ClientAuthorizationMiddleware(
     IdentityContext db,
     IClock clock
 ) : IMiddleware
@@ -22,10 +22,10 @@ public class AuthorizationMiddleware(
         }
 
         var token = ctx.GetToken();
-        if (token == null || token.Expires > clock.GetCurrentInstant())
+        if (token == null || token.Expires < clock.GetCurrentInstant())
             throw new ApiError.Unauthorized("This endpoint requires an authenticated user.");
-        if (attribute.Scopes.Length > 0 && attribute.Scopes.Except(token.Scopes).Any())
-            throw new ApiError.Forbidden("This endpoint requires ungranted scopes.", attribute.Scopes.Except(token.Scopes));
+        if (attribute.Scopes.Length > 0 && attribute.Scopes.Except(token.Scopes.ExpandScopes()).Any())
+            throw new ApiError.Forbidden("This endpoint requires ungranted scopes.", attribute.Scopes.Except(token.Scopes.ExpandScopes()));
 
         await next(ctx);
     }

Foxchat.Identity/Program.cs

@@ -1,20 +1,31 @@
 using Newtonsoft.Json.Serialization;
 using Serilog;
 using Foxchat.Core;
+using Foxchat.Core.Extensions;
 using Foxchat.Identity;
 using Foxchat.Identity.Database;
 using Foxchat.Identity.Services;
 using Foxchat.Identity.Extensions;
+using Newtonsoft.Json;
 
 var builder = WebApplication.CreateBuilder(args);
 
 var config = builder.AddConfiguration<InstanceConfig>("identity.ini");
 
-builder.AddSerilog(config.LogEventLevel);
+builder.AddSerilog();
 
 await BuildInfo.ReadBuildInfo();
 Log.Information("Starting Foxchat.Identity {Version} ({Hash})", BuildInfo.Version, BuildInfo.Hash);
 
+// Set the default converter to snake case as we use it in a couple places.
+JsonConvert.DefaultSettings = () => new JsonSerializerSettings
+{
+    ContractResolver = new DefaultContractResolver
+    {
+        NamingStrategy = new SnakeCaseNamingStrategy()
+    }
+};
+
 builder.Services
     .AddControllers()
     .AddNewtonsoftJson(options =>
@@ -41,7 +52,7 @@ app.UseCustomMiddleware();
 app.MapControllers();
 
 using (var scope = app.Services.CreateScope())
-using (var context = scope.ServiceProvider.GetRequiredService<IdentityContext>())
+await using (var context = scope.ServiceProvider.GetRequiredService<IdentityContext>())
 {
     Log.Information("Initializing instance keypair...");
     if (await context.InitializeInstanceAsync())

Foxchat.Identity/Services/ChatInstanceResolverService.cs

@@ -31,7 +31,7 @@ public class ChatInstanceResolverService(ILogger logger, RequestSigningService r
             PublicKey = resp.PublicKey,
             Status = ChatInstance.InstanceStatus.Active,
         };
-        await db.AddAsync(instance);
+        db.Add(instance);
         await db.SaveChangesAsync();
 
         return instance;

Foxchat.Identity/Utils/OauthUtils.cs

@@ -1,8 +1,15 @@
+using Foxchat.Core;
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Database.Models;
+
 namespace Foxchat.Identity.Utils;
 
 public static class OauthUtils
 {
-    public static readonly string[] Scopes = ["identify", "chat_client"];
+    public const string ClientCredentials = "client_credentials";
+    public const string AuthorizationCode = "authorization_code";
+
+    public static readonly string[] Scopes = ["identify", "email", "guilds", "chat_client"];
 
     private static readonly string[] ForbiddenSchemes = ["javascript", "file", "data", "mailto", "tel"];
     private const string OobUri = "urn:ietf:wg:oauth:2.0:oob";
@@ -20,4 +27,8 @@ public static class OauthUtils
             return false;
         }
     }
-}
+
+    public static string[] ExpandScopes(this string[] scopes) => scopes.Contains("chat_client")
+        ? Scopes
+        : scopes;
+}

Foxchat.Identity/identity.ini

@@ -2,11 +2,6 @@ Host = localhost
 Port = 7611
 Domain = id.fox.localhost
 
-; The level to log things at. Valid settings: Verbose, Debug, Information, Warning, Error, Fatal
-LogEventLevel = Debug
-; Optional logging to Seq
-SeqLogUrl = http://localhost:5341
-
 [Database]
 ; The database URL in ADO.NET format.
 Url = "Host=localhost;Database=foxchat_cs_ident;Username=foxchat;Password=password"
@@ -15,3 +10,11 @@ Url = "Host=localhost;Database=foxchat_cs_ident;Username=foxchat;Password=passwo
 Timeout = 5
 ; The maximum number of open connections. Defaults to 50.
 MaxPoolSize = 500
+
+[Logging]
+; The level to log things at. Valid settings: Verbose, Debug, Information, Warning, Error, Fatal
+LogEventLevel = Debug
+; Whether to log SQL queries.
+LogQueries = true
+; Optional logging to Seq
+SeqLogUrl = http://localhost:5341