从appsettings.json向.net核心控制台应用程序添加多个终结点路由

Posted 2021-04-11

我正在使用.net core 3.1来构建充当事件处理程序API的控制台应用程序。

该应用程序捕获对数据库的更改，并将这些更改实时定向到其他API。对“客户”的更新转到“ customerAPI”，“产品”转到“ productAPI”，依此类推。这意味着我有一个如下的appsettings.Local.json：

 "DBConnectionStrings": {
    "DefaultConnection": "AccountEndpoint=(my account)",
    "SourceDatabaseName": "MyDB",
    "SourceContainerName": "MySource",
    "LeasesContainerName": "MyLease",
    "PartitionKey": "/id"
  },
  "EndpointAPIStrings": {
    "Endpoint1": {
      "EndpointUrl": "https://localhost:7777",
      "Username": "myusername1",
      "Password": "mypassword1",
    "Endpoint2": {
      "EndpointUrl": "https://localhost:8888",
      "Username": "myusername2",
      "Password": "mypassword2",
    "Endpoint3": {
      "EndpointUrl": "https://localhost:9999",
      "Username": "myusername3",
      "Password": "mypassword3"
    ...
    }

我目前正在使用一种app脚的方法将其声明为EnvironmentVariables，以从我的Main那里获取它们，在Main中将其配置构建到我的CallAPI Task。

主要：

public static async Task Main(string[] args)
{
    ...
    IConfiguration configuration = BuildConfiguration(environmentName);
    CosmosClient cosmosClient = BuildCosmosClient(configuration);

    Environment.SetEnvironmentVariable("EndpointUrl", configuration["EndpointAPIStrings:Endpoint1:EndpointURL"]);
    Environment.SetEnvironmentVariable("Username", configuration["EndpointAPIStrings:Endpoint1:Username"]);
    Environment.SetEnvironmentVariable("Password", configuration["EndpointAPIStrings:Endpoint1:Password"]);
    ...
}

代理功能：

...
if (entityType == "myproduct")
{
    var entity = "products";
    var result = await Task.Run(() => CallAPIAsync(entity, item));
}
...

任务CallAPI：

public static async Task<HttpResponseMessage> CallAPIAsync(string entity, ProcessedItem item)
{
    using (var client = new HttpClient())
    {
        Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
        var endpointUrl = Environment.GetEnvironmentVariable("EndpointUrl");
        var uri = new Uri($"{endpointUrl}/api/{entity}/{item.Id}/propagate");
        string username = Environment.GetEnvironmentVariable("Username");
        string password = Environment.GetEnvironmentVariable("Password");
        ...
    }
}

这显然仅适用于第一个端点，而忽略其他端点。

我该如何重构它以将所有EndpointAPIString的值获取到我的CallAPI任务中？

答案

您可以为其创建一个类，然后将值读入该类。也可以将其更改为JSON中的列表会很好。我会做的步骤：

1. 将'EndpointAPIStrings'更改为数组：

   {
     "EndpointAPIStrings":[
       {
          "Id":"Endpoint1",
          "EndpointUrl":"https://localhost:7777",
          "Username":"myusername1",
          "Password":"mypassword1"
       },
       {
          "Id":"Endpoint2",
          "EndpointUrl":"https://localhost:8888",
          "Username":"myusername2",
          "Password":"mypassword2"
       },
       {
          "Id":"Endpoint3",
          "EndpointUrl":"https://localhost:9999",
          "Username":"myusername3",
          "Password":"mypassword3"
       }
     ]
   }
   

2. 创建一个定义JSON数组中对象的C＃类：

   public sealed class EndPoint {
       public string Id { get; set; }
   
       public string EndPointUrl { get; set; }
   
       public string Username { get; set; }
   
       public string Password { get; set; }
   }
   

3. 从配置中更改数据检索：

   IConfiguration configuration = BuildConfiguration(environmentName);
   CosmosClient cosmosClient = BuildCosmosClient(configuration);
   
   List<EndPoint> endPoints = configuration.GetSection("EndPointAPIStrings").Get<List<EndPoint>>();
   

---

现在，所有端点都在endPoints变量中。您可以按照自己的喜好删除属性并将其添加到JSON中，唯一需要做的就是相应地更改类。 请注意，为了获得成功的映射，您需要在JSON和C＃类中使用相同的名称。

另一答案

我已经在Windows Service .net Core 3.1应用程序中完成了此操作，非常相似。本质上，当您在program.cs中调用IHostBuilder函数时]

public static IHostBuilder CreateHostBuilder(string[] args) =>
            Host.CreateDefaultBuilder(args)
                .UseWindowsService()
                .ConfigureLogging(loggerFactory => loggerFactory.AddEventLog())
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHostedService<Worker>();
                });
默认情况下，您可以从appsettings.json访问配置变量。然后可以在您的主要启动或执行功能中进行访问：

private readonly ILogger<Worker> _logger;

private readonly IServiceScopeFactory _serviceScopeFactory;

private readonly IConfiguration _config;

public Worker(ILogger<Worker> logger, IServiceScopeFactory serviceScopeFactory, IConfiguration config)
            {
                _logger = logger;
                _serviceScopeFactory = serviceScopeFactory;
                _config = config;
            }  
然后在您的main或execute函数中：

protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            // Must be a scoped process in order to run correctly
            using var scope = _serviceScopeFactory.CreateScope();
            // Start timer and begin log
            var startTime = DateTime.UtcNow;
            var env = _config.GetValue<string>("ENV");
            var stageTable = _config.GetValue<string>("StageTable");
            var prevTable = _config.GetValue<string>("PrevTable");
            var mainTable = _config.GetValue<string>("MainTable");
            var sqlConnectionString = _config.GetValue<string>("SqlConnString_" + env);
            var excelConnectionString = _config.GetValue<string>("ExcelConnectionString1") +
                                        _config.GetValue<string>("ExcelFilePath_" + env) +
                                        _config.GetValue<string>("ExcelFileName") +
                                        _config.GetValue<string>("ExcelConnectionString2");
带有一个appsettings.json，如：

"ENV": "LOCAL",
"StageTable": "Staging",
"PrevTable": "Previous",
"MainTable": "Courses",