在ASP.net Core 2中管理设置

Question

I am converting an MVC 5 application to Core 2, and am confused over the settings.

I have a service that connects to an API server; The API server address is stored in a AppSettings.json configuration file as there is a development and production version.

"EtimeSettings": {
    "Api_Server": "123.123.123.123"
}

Having read some blogs, I have added the following code to startup.cs ConfigureServices :

services.AddMvc();

var eTimeSettings = new EtimeSettingsModel();
Configuration.Bind("EtimeSettings", eTimeSettings);
services.AddSingleton(eTimeSettings);

I cannot figure out how to retrieve these values in my API Service.

I was though able to retrieve the values using the following code;

public string GetApiServer()
{
    var builder = new ConfigurationBuilder()
    .SetBasePath(Directory.GetCurrentDirectory())
    .AddJsonFile("appsettings.json");

    EtimeSettingsModel et = new EtimeSettingsModel();
    IConfiguration Configuration = builder.Build();
    Configuration.GetSection("EtimeSettings").Bind(et);
    var apiServer = Configuration["EtimeSettings:Api_Server"];
    return apiServer;
}

But I really don't believe that this is the best way.

What am I missing?

Answer 1

Referencing Options pattern in ASP.NET Core Documentation

Assuming

public class EtimeSettingsModel {
    public string Api_Server { get; set; }
}

To setup the IOptions<TOptions> service you call the AddOptions extension method during startup in your ConfigureServices method. You configure options using the Configure<TOptions> extension method. You can configure options using a delegate or by binding your options to configuration:

public void ConfigureServices(IServiceCollection services) {

    //...

    // Setup options with DI
    services.AddOptions();

    // Configure EtimeSettingsModel using config by installing 
    // Microsoft.Extensions.Options.ConfigurationExtensions
    // Bind options using a sub-section of the appsettings.json file.
    services.Configure<EtimeSettingsModel>(Configuration.GetSection("EtimeSettings"));

    services.AddMvc();

    //...       
}

Options can be injected into your application using the IOptions<TOptions> accessor service.

private readonly EtimeSettingsModel eTimeSettings;
public MyAPIService(IOptions<EtimeSettingsModel> eTimeSettings) {
    this.eTimeSettings = eTimeSettings.Value;
}