阅读Main Program.cs中的appsettings.json [英] Read appsettings.json in Main Program.cs

问题描述

首先，我的主要目的是为应用程序动态设置IP和端口.

First of all my main purpose is to setup the IP and Port for my application dynamically.

我正在使用IConfiguration注入json配置文件，就像提到的一些教程一样.

I'm using IConfiguration to inject a json config file, like some tutorial mentioned.

但是，我无法在Program.cs中检索配置，因为我的WebHostBuilder将同时使用StartUp和Url.

However, I can't retrieve the configuration in Program.cs, because my WebHostBuilder will use the StartUp and Url at the same time.

因此，在主机建立时，我的配置中没有任何内容.

So at the time the host build up, there is nothing in my configuration.

WebProtocolSettings settings_Web = new WebProtocolSettings();
var host = new WebHostBuilder()
                .UseIISIntegration()
                .UseKestrel()
                .UseContentRoot(Directory.GetCurrentDirectory())
                .UseStartup<Startup>()
                .UseUrls(settings_Web.Url + ":" + settings_Web.Port)
                .Build();

在Startup.cs

In Startup.cs

public Startup(IHostingEnvironment env)
{
    // Set up configuration sources.
    var builder = new ConfigurationBuilder()
        .SetBasePath(env.ContentRootPath)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true);

    Configuration = builder.Build();
}

public IConfigurationRoot Configuration { get; set; }

public void ConfigureServices(IServiceCollection services)
{
    // Adds services required for using options.
    services.AddOptions();

    var _WebProtocolSettings = Configuration.GetSection("WebProtocolSettings");

    // Register the IConfiguration instance
    services.Configure<WebProtocolSettings>(_WebProtocolSettings);
}

我的appsettings.json:

My appsettings.json:

{
    "WebProtocolSettings": {
        "Url": "127.0.0.1",
        "Port": 5050
    }
}

我的WebProtocolSettings.cs:

My WebProtocolSettings.cs:

public class WebProtocolSettings
{
    public string Url { get; set; }
    public int Port { get; set; }
}

推荐答案

您必须在main方法中构建配置，获取该部分并将其绑定到您的模型.没办法.

You must build a configuration in your main method, get the section and bind it to your model. No way around it.

public static void Main(string[] args)
{
    var config = new ConfigurationBuilder()
        .AddJsonFile("appsettings.json", optional: false)
        .Build();

    WebProtocolSettings settings_Web = new WebProtocolSettings();
    config.GetSection("WebProtocolSettings").Bind(settings_Web);

    var host = new WebHostBuilder()
            .UseIISIntegration()
            .UseKestrel()
            .UseContentRoot(Directory.GetCurrentDirectory())
            .UseStartup<Startup>()
            .UseUrls(settings_Web.Url + ":" + settings_Web.Port)
            .Build()

    host.Run();
}

更新

一种替代方法是按照

Update

An alternative way of doing it is by passing the configuration to UseConfiguration as described in the

public static void Main(string[] args)
{
    var config = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("hosting.json", optional: true)
        .AddCommandLine(args)
        .Build();

    var host = new WebHostBuilder()
        .UseUrls("http://*:5000")
        .UseConfiguration(config)
        .UseKestrel()
        .Configure(app =>
        {
            app.Run(context => 
                context.Response.WriteAsync("Hello, World!"));
        })
        .Build();

    host.Run();
}

或在ASP.NET Core> 2.0中

or in ASP.NET Core > 2.0

public static void Main(string[] args)
{
    BuildWebHost(args).Run();
}

public static IWebHost BuildWebHost(string[] args)
{
    var config = new ConfigurationBuilder()
        .SetBasePath(Directory.GetCurrentDirectory())
        .AddJsonFile("hosting.json", optional: true)
        .AddCommandLine(args)
        .Build();

    return WebHost.CreateDefaultBuilder(args)
        .UseUrls("http://*:5000")
        .UseConfiguration(config)
        .Configure(app =>
        {
            app.Run(context => 
                context.Response.WriteAsync("Hello, World!"));
        })
        .Build();
}

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