Initial commit

MealPlan.Api/Middleware/ExceptionMiddleware.cs

@@ -0,0 +1,62 @@
+using System.Text.Json;
+
+namespace MealPlan.Api.Middleware;
+
+/// <summary>
+/// Converts unhandled exceptions into RFC-7807-style JSON problem responses and logs them.
+/// Internal details are never leaked to the client.
+/// </summary>
+public class ExceptionMiddleware
+{
+    private readonly RequestDelegate _next;
+    private readonly ILogger<ExceptionMiddleware> _logger;
+
+    public ExceptionMiddleware(RequestDelegate next, ILogger<ExceptionMiddleware> logger)
+    {
+        _next = next;
+        _logger = logger;
+    }
+
+    public async Task InvokeAsync(HttpContext context)
+    {
+        try
+        {
+            await _next(context);
+        }
+        catch (OperationCanceledException) when (context.RequestAborted.IsCancellationRequested)
+        {
+            // Client disconnected; nothing actionable to report.
+            _logger.LogDebug("Request {Path} was cancelled by the client", context.Request.Path);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Unhandled exception for {Method} {Path}",
+                context.Request.Method, context.Request.Path);
+
+            if (context.Response.HasStarted)
+            {
+                throw;
+            }
+
+            context.Response.Clear();
+            context.Response.StatusCode = StatusCodes.Status500InternalServerError;
+            context.Response.ContentType = "application/problem+json";
+
+            var payload = new
+            {
+                type = "https://httpstatuses.io/500",
+                title = "An unexpected error occurred.",
+                status = StatusCodes.Status500InternalServerError,
+                traceId = context.TraceIdentifier,
+            };
+
+            await context.Response.WriteAsync(JsonSerializer.Serialize(payload));
+        }
+    }
+}
+
+public static class ExceptionMiddlewareExtensions
+{
+    public static IApplicationBuilder UseExceptionMiddleware(this IApplicationBuilder app) =>
+        app.UseMiddleware<ExceptionMiddleware>();
+}