TaskAPI/Middleware/IdempontencyMiddleware.cs - master - ilyamikhaylov07/integration_solution_course

TaskAPI/Middleware/IdempontencyMiddleware.cs

56 строк2 KB

Ilya

Init

24 сен 2025, 16:32

24 сен 2025, 16:32360074e

using Microsoft.Extensions.Caching.Memory;

namespace TaskAPI.Middleware
{
    public class IdempotencyMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly IMemoryCache _cache;

        public IdempotencyMiddleware(RequestDelegate next, IMemoryCache cache)
        {
            _next = next;
            _cache = cache;
        }

        /// <summary>
        /// Если от клиента приходит POST запрос с заголовком "Idempotency-Key", то применяется middleware
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public async Task InvokeAsync(HttpContext context)
        {
            if (context.Request.Method != HttpMethods.Post ||
                !context.Request.Headers.TryGetValue("Idempotency-Key", out var keyValue))
            {
                await _next(context);
                return;
            }

            var key = keyValue.ToString();

            if (_cache.TryGetValue(key, out string cachedResponse))
            {
                context.Response.StatusCode = StatusCodes.Status200OK;
                context.Response.ContentType = "application/json";
                await context.Response.WriteAsync(cachedResponse);
                return;
            }

            var originalBodyStream = context.Response.Body;
            using var responseBody = new MemoryStream();
            context.Response.Body = responseBody;

            await _next(context);

            context.Response.Body.Seek(0, SeekOrigin.Begin);
            var responseText = await new StreamReader(context.Response.Body).ReadToEndAsync();
            context.Response.Body.Seek(0, SeekOrigin.Begin);

            _cache.Set(key, responseText, TimeSpan.FromHours(2));

            await responseBody.CopyToAsync(originalBodyStream);
        }
    }

}