Accessing Configuration as service asp.net core

Question

I am trying to access AppSettings as service in my ASP.NET core WebAPI. When I do Configuration.GetSection("AppSettings") I get null but I could access the configuration values as Configuration["AppSettings:StorageConnectionKey:AccountName"]. I am not sure what I am doing wrong.

My Startup.cs is shown below

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Library;

namespace Athraya
{
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json")
               // .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }

        public IConfiguration Configuration { get; set; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            // Add framework services.
            services.AddMvc();

            services.AddOptions();


            services.Configure<AppSettings>(options => Configuration.GetSection("AppSettings"));

            // *If* you need access to generic IConfiguration this is **required**
            services.AddSingleton<IConfiguration>(Configuration);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
        {
            loggerFactory.AddConsole(Configuration.GetSection("Logging"));
            loggerFactory.AddDebug();

            app.UseMvc();
        }
    }
}

and my appsetting is

    {
  "AppSettings": {
    "StorageConnectionKey": {
      "AccountName": "myaccountName",
      "AccountKey": "abc"

    },
    "CloudContainerkey": {
      "ContainerName": "mycontainername",
      "FileName": "db.dat"
    }
  },
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Warning"
    }
  }
}

I have a Library Project where I have the classes needed

    using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Library
{
    public class AppSettings
    {
        public StorageConnectionKey storageKey {get; set; }
        public CloudContainerKey containerKey { get; set; }
    }
}

    namespace Library
{
    public class CloudContainerKey
    {
        public string ContainerName { get; set; }
        public string FileName { get; set; }
    }
}

    namespace Library
{
    public class StorageConnectionKey
    {
        public string AccountName { get; set; }
        public string AccountKey { get; set; }
    }
}

I am trying to get it in controller as

public class ValuesController : Controller
    {
        private readonly AppSettings _appSettings;

        public ValuesController(IOptions<AppSettings> settings)
        {
            _appSettings = settings.Value;
        }
}

Any Help here is appreciated.

Set · Accepted Answer · 2017-03-13 19:02:35Z

1

To setup AppSettings using IConfiguration instance use:

services.Configure<AppSettings>(Configuration.GetSection("AppSettings"));

Also, you need to use the same property name, as your settings parameters. Modify your AppSettings to:

public class AppSettings
{
    public StorageConnectionKey StorageConnectionKey {get; set; }
    public CloudContainerKey CloudContainerKey { get; set; }
}

In your case, you have null, as you use the extension method, that allows registering an action used to configure option manually. If you look into method definition, you will see:

//
// Summary:
//     Registers an action used to configure a particular type of options. ///
//
// Parameters:
//   services:
//     The Microsoft.Extensions.DependencyInjection.IServiceCollection to add the services
//     to.
//
//   configureOptions:
//     The action used to configure the options.
//
// Type parameters:
//   TOptions:
//     The options type to be configured.
//
// Returns:
//     The Microsoft.Extensions.DependencyInjection.IServiceCollection so that additional
//     calls can be chained.
public static IServiceCollection Configure<TOptions>(this IServiceCollection services,
     Action<TOptions> configureOptions) where TOptions : class;

In other words, when you use follow code, you register the lambda function and already use the instance of AppSettings:

services.Configure<AppSettings>(option =>
{
    // option here is the AppSettings and so we can override value like:
    option.StorageConnectionKey = "some_new_value";
});

edited Mar 13, 2017 at 19:02

answered Mar 13, 2017 at 18:33

Set

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4 Comments

Vijay aravind Over a year ago

I still get null when you have it that way services.Configure<AppSettings>(Configuration.GetSection("AppSettings"));

Vijay aravind Over a year ago

How do you think I should change my startup so i can access it in the controller as I have mentioned. I tried to follow this blog codefluff.com/getting-configuration-settings-asp-net-core-mvc. Please let me know what I am missing is something changed in ASP.NET Core again

Set Over a year ago

@Vijayaravind have updated answer - you need to rename propertis in your option classes to be the same, as setting parameters names.

Vijay aravind Over a year ago

Thank you so much. that was it. I did not realize that at all.. Appreciate your help.

juunas · Accepted Answer · 2017-03-13 18:23:29Z

0

I think it should be like this:

services.Configure<AppSettings>(Configuration.GetSection("AppSettings"));

answered Mar 13, 2017 at 18:23

juunas

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1 Comment

Vijay aravind Over a year ago

This is how I originally had it and I still got Null so I changed it based on this blog weblog.west-wind.com/posts/2016/may/23/…

Waqas Anwar · Accepted Answer · 2020-10-13 03:47:49Z

Let's say you have following settings

"MyApplication": {
    "Name": "Demo Configuration Application (Development)",
    "Version": "1.1",
    "DefaultUrl": "http://localhost:3030",
    "Support": {
      "Email": "[email protected]",
      "Phone": "123456789"
  }
}

First you need to create corresponding C# classes where property names should match with the above JSON settings.

public class ApplicationOptions
{
     public const string MyApplication = "MyApplication";
 
     public string Name { get; set; }
     public decimal Version { get; set; }
     public string DefaultUrl { get; set; }
 
     public SupportOptions Support { get; set; }
}
 
public class SupportOptions
{
     public const string Support = "Support";
 
     public string Email { get; set; }
     public string Phone { get; set; }
}

Next you need to bind your configuration settings in Startup.cs file as follows:

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<ApplicationOptions>(Configuration.GetSection(ApplicationOptions.MyApplication));     
    ...
}

Next you can inject the configuration in Controllers or Services using Options pattern

private readonly ApplicationOptions _options;
 
public HomeController(IOptions<ApplicationOptions> options)
{
    _options = options.Value;
}

Finally you can read settings as follows:

public IActionResult Index()
{
    ViewBag.ApplicationName = _options.Name;
    ViewBag.ApplicationVersion = _options.Version;
    ViewBag.ApplicationUrl = _options.DefaultUrl;
 
    ViewBag.SupportEmail = _options.Support.Email;
    ViewBag.SupportPhone = _options.Support.Phone;
 
    return View();
}

You can read my full blog post A Step by Step Guide for ASP.NET Core Configuration explaining all of these steps in greater detail.

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