【发布时间】：2019-08-25 03:19:48
【问题描述】：
.NET Core 配置允许添加许多选项（环境变量、json 文件、命令行参数）。
我只是不知道如何通过代码填充它并找到答案。
我正在为配置的扩展方法编写单元测试，我认为通过代码在单元测试中填充它比为每个测试加载专用的 json 文件更容易。
我当前的代码：
[Fact]
public void Test_IsConfigured_Positive()
{
// test against this configuration
IConfiguration config = new ConfigurationBuilder()
// how to populate it via code
.Build();
// the extension method to test
Assert.True(config.IsConfigured());
}
更新：
一种特殊情况是“空部分”，它在 json 中看起来像这样。
{
"MySection": {
// the existence of the section activates something triggering IsConfigured to be true but does not overwrite any default value
}
}
更新 2：
正如 Matthew 在 cmets 中指出的那样，在 json 中有一个空白部分与根本没有该部分给出的结果相同。我提炼了一个例子，是的，就是这样。我期待不同的行为是错误的。
那么我该怎么做以及我期望什么：
我正在为 IConfiguration 的 2 个扩展方法编写单元测试（实际上是因为 Get...Settings 方法中的值绑定由于某种原因不起作用（但这是一个不同的主题）。它们看起来像这样：
public static bool IsService1Configured(this IConfiguration configuration)
{
return configuration.GetSection("Service1").Exists();
}
public static MyService1Settings GetService1Settings(this IConfiguration configuration)
{
if (!configuration.IsService1Configured()) return null;
MyService1Settings settings = new MyService1Settings();
configuration.Bind("Service1", settings);
return settings;
}
我的误解是，如果我在 appsettings 中放置一个空白部分，IsService1Configured() 方法将返回 true（现在显然是错误的）。我期望的不同之处在于现在有一个空部分 GetService1Settings() 方法返回 null 而不是我期望的 MyService1Settings 具有所有默认值。
幸运的是，这仍然对我有用，因为我不会有空白部分（或者现在知道我必须避免这些情况）。这只是我在编写单元测试时遇到的一个理论案例。
更进一步（对于那些有兴趣的人）。
我用它做什么？基于配置的服务激活/停用。
我有一个应用程序，其中编译了一项服务/一些服务。根据部署，我需要完全激活/停用服务。这是因为某些（本地或测试设置）无法完全访问完整的基础架构（辅助服务，如缓存、指标......）。我通过 appsettings 做到这一点。如果服务已配置（配置部分存在），它将被添加。如果配置部分不存在，它将不会被使用。
提炼示例的完整代码如下。
- 在 Visual Studio 中，从模板中创建一个名为 WebApplication1 的新 API（无需 HTTPS 和身份验证）
- 删除 Startup 类和 appsettings.Development.json
- 将 Program.cs 中的代码替换为以下代码
- 现在在 appsettings.json 中，您可以通过添加/删除
Service1和Service2部分来激活/停用服务
using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System;
namespace WebApplication1
{
public class MyService1Settings
{
public int? Value1 { get; set; }
public int Value2 { get; set; }
public int Value3 { get; set; } = -1;
}
public static class Service1Extensions
{
public static bool IsService1Configured(this IConfiguration configuration)
{
return configuration.GetSection("Service1").Exists();
}
public static MyService1Settings GetService1Settings(this IConfiguration configuration)
{
if (!configuration.IsService1Configured()) return null;
MyService1Settings settings = new MyService1Settings();
configuration.Bind("Service1", settings);
return settings;
}
public static IServiceCollection AddService1(this IServiceCollection services, IConfiguration configuration, ILogger logger)
{
MyService1Settings settings = configuration.GetService1Settings();
if (settings == null) throw new Exception("loaded MyService1Settings are null (did you forget to check IsConfigured in Startup.ConfigureServices?) ");
logger.LogAsJson(settings, "MyServiceSettings1: ");
// do what ever needs to be done
return services;
}
public static IApplicationBuilder UseService1(this IApplicationBuilder app, IConfiguration configuration, ILogger logger)
{
// do what ever needs to be done
return app;
}
}
public class Program
{
public static void Main(string[] args)
{
CreateWebHostBuilder(args).Build().Run();
}
public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
WebHost.CreateDefaultBuilder(args)
.ConfigureLogging
(
builder =>
{
builder.AddDebug();
builder.AddConsole();
}
)
.UseStartup<Startup>();
}
public class Startup
{
public IConfiguration Configuration { get; }
public ILogger<Startup> Logger { get; }
public Startup(IConfiguration configuration, ILoggerFactory loggerFactory)
{
Configuration = configuration;
Logger = loggerFactory.CreateLogger<Startup>();
}
// This method gets called by the runtime. Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
{
// flavour 1: needs check(s) in Startup method(s) or will raise an exception
if (Configuration.IsService1Configured()) {
Logger.LogInformation("service 1 is activated and added");
services.AddService1(Configuration, Logger);
} else
Logger.LogInformation("service 1 is deactivated and not added");
// flavour 2: checks are done in the extension methods and no Startup cluttering
services.AddOptionalService2(Configuration, Logger);
services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
if (env.IsDevelopment()) app.UseDeveloperExceptionPage();
// flavour 1: needs check(s) in Startup method(s) or will raise an exception
if (Configuration.IsService1Configured()) {
Logger.LogInformation("service 1 is activated and used");
app.UseService1(Configuration, Logger); }
else
Logger.LogInformation("service 1 is deactivated and not used");
// flavour 2: checks are done in the extension methods and no Startup cluttering
app.UseOptionalService2(Configuration, Logger);
app.UseMvc();
}
}
public class MyService2Settings
{
public int? Value1 { get; set; }
public int Value2 { get; set; }
public int Value3 { get; set; } = -1;
}
public static class Service2Extensions
{
public static bool IsService2Configured(this IConfiguration configuration)
{
return configuration.GetSection("Service2").Exists();
}
public static MyService2Settings GetService2Settings(this IConfiguration configuration)
{
if (!configuration.IsService2Configured()) return null;
MyService2Settings settings = new MyService2Settings();
configuration.Bind("Service2", settings);
return settings;
}
public static IServiceCollection AddOptionalService2(this IServiceCollection services, IConfiguration configuration, ILogger logger)
{
if (!configuration.IsService2Configured())
{
logger.LogInformation("service 2 is deactivated and not added");
return services;
}
logger.LogInformation("service 2 is activated and added");
MyService2Settings settings = configuration.GetService2Settings();
if (settings == null) throw new Exception("some settings loading bug occured");
logger.LogAsJson(settings, "MyService2Settings: ");
// do what ever needs to be done
return services;
}
public static IApplicationBuilder UseOptionalService2(this IApplicationBuilder app, IConfiguration configuration, ILogger logger)
{
if (!configuration.IsService2Configured())
{
logger.LogInformation("service 2 is deactivated and not used");
return app;
}
logger.LogInformation("service 2 is activated and used");
// do what ever needs to be done
return app;
}
}
public static class LoggerExtensions
{
public static void LogAsJson(this ILogger logger, object obj, string prefix = null)
{
logger.LogInformation(prefix ?? string.Empty) + ((obj == null) ? "null" : JsonConvert.SerializeObject(obj, Formatting.Indented)));
}
}
}
【问题讨论】：
标签： asp.net-core .net-core xunit asp.net-core-2.2 .net-core-2.2