Asp.net core中实现自动更新的Option的方法示例_实用技巧_

 public class RefreshableOptions { public int IncreasementCount { get; set; } } 

 public class AutoRefreshConfigurationSource : IConfigurationSource { public IConfigurationProvider Build(IConfigurationBuilder builder) { return new AutoRefreshConfigurationProvider(); } } public class AutoRefreshConfigurationProvider : ConfigurationProvider { private int count = 0; private bool isChanged; public AutoRefreshConfigurationProvider() : base() { Timer timer = new Timer(TimerCallback); timer.Change(1000, 3000); } public override void Load() { var beforeData = Data; // 这里采用硬编码指定option的路径 Data = new Dictionary() { { "AutoRefreshOptions:IncreasementCount", count.ToString() } }; isChanged = IsDictionaryChanged(beforeData, Data); } private void TimerCallback(object state) { count++; this.Load(); if (isChanged) { base.OnReload();//通知IConfiguration实例, 有参数发生了改变 isChanged = false; } } //判断两个Idictionary是否有不同的帮助方法 private static bool IsDictionaryChanged(IDictionary before, IDictionary after) { if (before == null && after == null) { return false; } if ((before == null) != (after == null)) { return true; } if (before.Count != after.Count) { return true; } var ignoreCaseBefore = new Dictionary(before, StringComparer.OrdinalIgnoreCase); foreach (var afterItemKey in after.Keys) { if (!ignoreCaseBefore.TryGetValue(afterItemKey, out var beforeItemValue)) { return true; } if (beforeItemValue != after[afterItemKey]) { return true; } ignoreCaseBefore.Remove(afterItemKey); } if (ignoreCaseBefore.Count > 0) { return true; } return false; } }

 public static class AutoRereshConfigurationExtensions { public static IConfigurationBuilder AddAutoRereshConfiguration(this IConfigurationBuilder builder) { return builder.Add(new AutoRefreshConfigurationSource()); } } 

 WebHost.CreateDefaultBuilder(args) .ConfigureAppConfiguration(config => { config.AddAutoRereshConfiguration(); }) .UseStartup(); 

 services.Configure(Configuration.GetSection("AutoRefreshOptions"));

 [Route("api/[controller]")] [ApiController] public class ValuesController : ControllerBase { private RefreshableOptions refreshableOptions; public ValuesController(IOptionsSnapshot refreshableOptions) { this.refreshableOptions = refreshableOptions.Value; } [HttpGet] public ActionResult> Get() { return new string[] { "value1", "value2", refreshableOptions.IncreasementCount.ToString() }; } }