add Idempotency

Author: Daniel-iel

src/RideSharingApp.Api/Middlewares/CorrelationIdMiddleware.cs

@@ -1,27 +1,23 @@
-using Microsoft.AspNetCore.Http;
-using System;
-using System.Threading.Tasks;
+namespace RideSharingApp.Api.Middlewares;
 
-namespace RideSharingApp.Api.Middlewares
+public class CorrelationIdMiddleware
 {
-    public class CorrelationIdMiddleware
+    private const string CorrelationIdHeader = "X-Correlation-Id";
+    private readonly RequestDelegate _next;
+
+    public CorrelationIdMiddleware(RequestDelegate next)
     {
-        private const string CorrelationIdHeader = "X-Correlation-Id";
-        private readonly RequestDelegate _next;
+        _next = next;
+    }
 
-        public CorrelationIdMiddleware(RequestDelegate next)
+    public Task InvokeAsync(HttpContext context)
+    {
+        if (!context.Request.Headers.ContainsKey(CorrelationIdHeader))
         {
-            _next = next;
+            context.Request.Headers[CorrelationIdHeader] = Guid.NewGuid().ToString();
         }
 
-        public async Task InvokeAsync(HttpContext context)
-        {
-            if (!context.Request.Headers.ContainsKey(CorrelationIdHeader))
-            {
-                context.Request.Headers[CorrelationIdHeader] = Guid.NewGuid().ToString();
-            }
-            context.Response.Headers[CorrelationIdHeader] = context.Request.Headers[CorrelationIdHeader];
-            await _next(context);
-        }
+        context.Response.Headers[CorrelationIdHeader] = context.Request.Headers[CorrelationIdHeader];
+        return _next(context);
     }
 }

src/RideSharingApp.Api/Middlewares/IdempotencyMiddleware.cs

@@ -0,0 +1,55 @@
+using System.Collections.Concurrent;
+
+namespace RideSharingApp.Api.Middlewares;
+
+public class IdempotencyMiddleware
+{
+    private readonly RequestDelegate _next;
+    private static readonly ConcurrentDictionary<string, string> _responses = new();
+
+    public IdempotencyMiddleware(RequestDelegate next)
+    {
+        _next = next;
+    }
+
+    public async Task InvokeAsync(HttpContext context)
+    {
+        if (context.Request.Method != HttpMethods.Post)
+        {
+            await _next(context);
+            return;
+        }
+
+        if (!context.Request.Headers.TryGetValue("Idempotency-Key", out var key))
+        {
+            context.Response.StatusCode = StatusCodes.Status400BadRequest;
+            await context.Response.WriteAsync("Missing Idempotency-Key header");
+            return;
+        }
+
+        if (_responses.TryGetValue(key!, out var cachedResponse))
+        {
+            context.Response.ContentType = "application/json";
+            await context.Response.WriteAsync(cachedResponse);
+            return;
+        }
+
+        var originalBodyStream = context.Response.Body;
+        await using var memoryStream = new MemoryStream();
+        context.Response.Body = memoryStream;
+
+        await _next(context);
+
+        memoryStream.Position = 0;
+        var responseText = await new StreamReader(memoryStream).ReadToEndAsync();
+
+        if (context.Response.StatusCode is >= 200 and < 300)
+        {
+            _responses[key!] = responseText;
+        }
+
+        memoryStream.Position = 0;
+        await memoryStream.CopyToAsync(originalBodyStream);
+        context.Response.Body = originalBodyStream;
+    }
+}