AcaMate_API/Program/Services/V1/PushService.cs

using System.Text;
using System.Text.Json;
using Back.Program.Common.Model;
using Back.Program.Models.Entities;
using Back.Program.Services.V1.Interfaces;
using Microsoft.Extensions.Options;
using Polly;
using Version = System.Version;

namespace Back.Program.Services.V1
{
    public class PushService: IPushService
    {
        private readonly HttpClient _httpClient;
        private readonly PushFileSetting _setting;

        public PushService(HttpClient httpClient, IOptions<PushFileSetting> options)
        {
            _httpClient = httpClient;
            _setting = options.Value;
        }

        public async Task SendPushNotificationAsync(string deviceToken, Payload payload)
        {
        
            // 존재 안하면 예외 던져 버리는거
            if (!File.Exists(_setting.p12Path) || !File.Exists(_setting.p12PWPath))
                throw new FileNotFoundException("[푸시] : p12 관련 파일 확인 필요");
        
            var jsonPayload = JsonSerializer.Serialize(payload);
            
            var request = new HttpRequestMessage(HttpMethod.Post, $"/3/device/{deviceToken}")
            {
                Content = new StringContent(jsonPayload, Encoding.UTF8, "application/json"),
                Version = new Version(2, 0) // HTTP/2 사용
            };

            // 필수 헤더 추가
            request.Headers.Add("apns-topic", _setting.apnsTopic);
            request.Headers.Add("apns-push-type", "alert");
            
            var policy = Policy.Handle<HttpRequestException>()
                .WaitAndRetryAsync(3, retryAttempt => 
                    TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));

            await policy.ExecuteAsync(async () =>
            {
                var response = await _httpClient.SendAsync(request);
                if (!response.IsSuccessStatusCode)
                {
                    var errorContent = await response.Content.ReadAsStringAsync();
                    throw new ServiceConnectionFailedException($"[푸시] : APNS 통신 실패 - {errorContent}");
                }
            });

        }

    }
}