.Net Core 3.1 Worker Service使用Appsettings.json。

Question

我正试图从我的worker服务的appsettings.json中获取我的应用程序设置（我只是假设这样做是正确的）。 我只做到了这一点，但实际上我无法理解如何使用Worker.cs中的appsettings。

下面是我在Program.cs中的内容

public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .ConfigureAppConfiguration((hostContext, config) =>
                {
                    // Configure the app here.
                    config
                        .SetBasePath(Environment.CurrentDirectory)
                        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                        .AddJsonFile($"appsettings.{hostContext.HostingEnvironment.EnvironmentName}.json", optional: true);

                    config.AddEnvironmentVariables();
                })
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHttpClient();
                    services.AddHostedService<Worker>();
                });

添加工人类

public class Worker : BackgroundService
    {
        private const int ThreadDelay = 5000;

        private readonly ILogger<Worker> _logger;
        private readonly HttpClient _httpClient;
        private readonly JsonSerializer _serializer;

        public Worker(ILogger<Worker> logger, IHttpClientFactory httpClient)
        {
            _logger = logger;
            _httpClient = httpClient.CreateClient();
            _serializer = new JsonSerializer();
        }

        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                _logger.LogInformation("Worker running at: {time}", DateTimeOffset.Now);

                var locations = GetLocations(stoppingToken);

                foreach(var item in locations)
                {

                }


                //lets start the thread again in 5 minutes
                await Task.Delay(ThreadDelay, stoppingToken);
            }
        }

        private string GetLocations(CancellationToken stoppingToken)
        {
            var result = string.Empty;

            var response = _httpClient.GetAsync($"https://", stoppingToken);


            return result;
        }

        private async Task TriggerPoll(CancellationToken stoppingToken)
        {
            var response = await _httpClient.GetAsync($"https://", stoppingToken);
        }

Answer 1

看起来你已经有了你所需要的东西，除了需要有一个 IConfiguration 在你 Worker 构造函数，所以框架的依赖注入容器会提供它。

经过下面的小改动，从appsettings中得到一个这样的值出来。_configuration["key"]

public class Worker : BackgroundService
{
        private const int ThreadDelay = 5000;

        private readonly IConfiguration _configuration;
        private readonly ILogger<Worker> _logger;
        private readonly HttpClient _httpClient;
        private readonly JsonSerializer _serializer;

        public Worker(IConfiguration configuration, ILogger<Worker> logger, IHttpClientFactory httpClient)
        {
            _configuration = configuration;
            _logger = logger;
            _httpClient = httpClient.CreateClient();
            _serializer = new JsonSerializer();
        }

        ...

}