.NetCore自定义配置源从配置中心读取配置的方法

  [Route("api/[controller]")]
 [ApiController]
 public class ConfigsController : ControllerBase
 {
  public List> Get()
  {
   var cOnfigs= new List>();
   configs.Add(new KeyValuePair("SecretKey","1238918290381923"));
   configs.Add(new KeyValuePair("ConnectionString", "user=123;password=123;server=."));

   return configs;
  }
 }

 public class MyConfigProvider : ConfigurationProvider
 {
  /// 

  /// 尝试从远程配置中心读取配置信息
  /// 
  public async override void Load()
  {
   var respOnse= "";
   try
   {
    var serverAddress = "http://localhost:5000";
    var client = new HttpClient();
    client.BaseAddress = new Uri(serverAddress);
    respOnse= await client.GetStringAsync("/api/configs");
   }
   catch (Exception ex)
   {
    //write err log
   }

   if (string.IsNullOrEmpty(response))
   {
    throw new Exception("Can not request configs from remote config center .");
   }

   var cOnfigs= JsonConvert.DeserializeObject>>(response);

   Data = new ConcurrentDictionary();

   configs.ForEach(c =>
   {
    Data.Add(c);
   });
  }
 
 }

 public class MyConfigSource : IConfigurationSource
 {
  public IConfigurationProvider Build(IConfigurationBuilder builder)
  {
   return new MyConfigProvider();
  }
 }

 public static class MyConfigBuilderExt
 {
  public static IConfigurationBuilder AddMyConfig(
   this IConfigurationBuilder builder
   )
  {
   return builder.Add(new MyConfigSource());
  }
 }

  public class Program
 {
  public static void Main(string[] args)
  {
   CreateWebHostBuilder(args).Build().Run();
  }

  public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
   WebHost.CreateDefaultBuilder(args)
   .ConfigureAppConfiguration((context, configBuiler) =>
   {
    configBuiler.AddMyConfig();
   })
   .UseStartup();
 }

 public class HomeController : Controller
 {
  IConfiguration _configuration;
  public HomeController(IConfiguration configuration)
  {
   _cOnfiguration= configuration;
  }

  public IActionResult Index()
  {
   var secretKey = _configuration["SecretKey"];
   var cOnnectionString= _configuration["ConnectionString"];

   ViewBag.SecretKey = secretKey;
   ViewBag.COnnectionString= connectionString;

   return View();
  }
  
 }

 @{
 ViewData["Title"] = "Test my config";
}


 SecretKey: @ViewBag.SecretKey


 ConnectionString: @ViewBag.ConnectionString

{
 "Logging": {
 "LogLevel": {
  "Default": "Warning"
 }
 },
 "AllowedHosts": "*",
 "myconfigServer": "http://localhost:5000"
}

 public class MyConfigProvider : ConfigurationProvider
 {
  private string _serverAddress;
  public MyConfigProvider()
  {
   var jsOnConfig= new JsonConfigurationSource();
   jsonConfig.FileProvider = new PhysicalFileProvider(Directory.GetCurrentDirectory());
   jsonConfig.Path = "appsettings.json";
   var jsOnProvider= new JsonConfigurationProvider(jsonConfig);
   jsonProvider.Load();

   jsonProvider.TryGet("myconfigServer", out string serverAddress);

   if (string.IsNullOrEmpty(serverAddress))
   {
    throw new Exception("Can not find myconfigServer's address from appsettings.json");
   }

   _serverAddress = serverAddress;
  }

  /// 

  /// 尝试从远程配置中心读取配置信息，当成功从配置中心读取信息的时候把配置写到本地的myconfig.json文件中，当配置中心无法访问的时候尝试从本地文件恢复配置。
  /// 
  public async override void Load()
  {
   var respOnse= "";
   try
   {
    var client = new HttpClient();
    client.BaseAddress = new Uri(_serverAddress);
    respOnse= await client.GetStringAsync("/api/configs");

    WriteToLocal(response);
   }
   catch (Exception ex)
   {
    //write err log
    respOnse= ReadFromLocal();
   }

   if (string.IsNullOrEmpty(response))
   {
    throw new Exception("Can not request configs from remote config center .");
   }

   var cOnfigs= JsonConvert.DeserializeObject>>(response);

   Data = new ConcurrentDictionary();

   configs.ForEach(c =>
   {
    Data.Add(c);
   });
  }

  private void WriteToLocal(string resp)
  {
   var file = Directory.GetCurrentDirectory() + "/myconfig.json";
   File.WriteAllText(file,resp);
  }

  private string ReadFromLocal()
  {
   var file = Directory.GetCurrentDirectory() + "/myconfig.json";
   return File.ReadAllText(file);
  }
 }