add error handler middleware

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/FoxchatError.cs

@@ -2,10 +2,12 @@ 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)
@@ -23,10 +25,10 @@ public class ApiError(string message, HttpStatusCode? statusCode = null) : Foxch
     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/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/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.Identity/Controllers/Oauth/AppsController.cs

@@ -1,8 +1,9 @@
 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;
@@ -29,9 +30,7 @@ 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(
             app.Id,

Foxchat.Identity/Controllers/Oauth/PasswordAuthController.cs

@@ -0,0 +1,22 @@
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Database;
+using Foxchat.Identity.Utils;
+using Microsoft.AspNetCore.Mvc;
+
+namespace Foxchat.Identity.Controllers.Oauth;
+
+[ApiController]
+[Authenticate]
+[Route("/_fox/ident/oauth/password")]
+public class PasswordAuthController(ILogger logger, IdentityContext db) : ControllerBase
+{
+    [HttpPost("register")]
+    public async Task<IActionResult> Register()
+    {
+        var app = HttpContext.GetApplicationOrThrow();
+
+        throw new NotImplementedException();
+    }
+
+    public record RegisterRequest();
+}

Foxchat.Identity/Controllers/Oauth/TokenController.cs

@@ -16,7 +16,7 @@ public class TokenController(ILogger logger, IdentityContext db, IClock clock) :
         var app = await db.GetApplicationAsync(req.ClientId, req.ClientSecret);
 
         var scopes = req.Scope.Split(' ');
-        if (app.Scopes.Except(scopes).Any())
+        if (scopes.Except(app.Scopes).Any())
         {
             throw new ApiError.BadRequest("Invalid or unauthorized scopes");
         }

Foxchat.Identity/Extensions/WebApplicationExtensions.cs

@@ -1,4 +1,4 @@
-using Foxchat.Identity.Authorization;
+using Foxchat.Identity.Middleware;
 
 namespace Foxchat.Identity.Extensions;
 
@@ -7,6 +7,7 @@ public static class WebApplicationExtensions
     public static IServiceCollection AddCustomMiddleware(this IServiceCollection services)
     {
         return services
+            .AddScoped<ErrorHandlerMiddleware>()
             .AddScoped<AuthenticationMiddleware>()
             .AddScoped<AuthorizationMiddleware>();
     }
@@ -14,6 +15,7 @@ public static class WebApplicationExtensions
     public static IApplicationBuilder UseCustomMiddleware(this IApplicationBuilder app)
     {
         return app
+            .UseMiddleware<ErrorHandlerMiddleware>()
             .UseMiddleware<AuthenticationMiddleware>()
             .UseMiddleware<AuthorizationMiddleware>();
     }

Foxchat.Identity/Middleware/AuthenticationMiddleware.cs

@@ -6,7 +6,7 @@ using Foxchat.Identity.Database.Models;
 using Microsoft.EntityFrameworkCore;
 using NodaTime;
 
-namespace Foxchat.Identity.Authorization;
+namespace Foxchat.Identity.Middleware;
 
 public class AuthenticationMiddleware(
     IdentityContext db,

Foxchat.Identity/Middleware/AuthorizationMiddleware.cs

@@ -1,9 +1,8 @@
-using System.Net;
 using Foxchat.Core;
 using Foxchat.Identity.Database;
 using NodaTime;
 
-namespace Foxchat.Identity.Authorization;
+namespace Foxchat.Identity.Middleware;
 
 public class AuthorizationMiddleware(
     IdentityContext db,

Foxchat.Identity/Middleware/ErrorHandlerMiddleware.cs

@@ -0,0 +1,87 @@
+
+using System.Net;
+using Foxchat.Core;
+using Foxchat.Core.Models.Http;
+using Newtonsoft.Json;
+using ApiError = Foxchat.Core.ApiError;
+using HttpApiError = Foxchat.Core.Models.Http.ApiError;
+
+namespace Foxchat.Identity.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.Identity/Program.cs

@@ -5,6 +5,7 @@ using Foxchat.Identity;
 using Foxchat.Identity.Database;
 using Foxchat.Identity.Services;
 using Foxchat.Identity.Extensions;
+using Newtonsoft.Json;
 
 var builder = WebApplication.CreateBuilder(args);
 
@@ -15,6 +16,15 @@ builder.AddSerilog(config.LogEventLevel);
 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 =>

Foxchat.Identity/Utils/OauthUtils.cs

@@ -1,3 +1,7 @@
+using Foxchat.Core;
+using Foxchat.Identity.Middleware;
+using Foxchat.Identity.Database.Models;
+
 namespace Foxchat.Identity.Utils;
 
 public static class OauthUtils
@@ -20,4 +24,11 @@ public static class OauthUtils
             return false;
         }
     }
+
+    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;
+    }
 }