How to get IOptions in ConfigureServices method?

Question

I have asp.net core application. I want to use IOptions pattern to inject values from appsettings.json. So I have a class SecurityHeaderOptions, and also have target class SecurityHeadersBuilder whose constructor takes IOptions<SecurityHeaderOptions> as parameter.

I know that .net core can implicitly create instance of SecurityHeadersBuilder by injecting IOptions<SecurityHeaderOptions> after registering both with container.

However i want to explicitly create instance of SecurityHeadersBuilder, call one of its method and then register the instance with the container.

public sealed class SecurityHeaderOptions {     public string FrameOption { get; set; }         public string XssProtection { get; set; } }   public class SecurityHeadersBuilder {     private readonly SecurityHeaderOptions _options = null;      public SecurityHeadersBuilder(IOptions<SecurityHeaderOptions> options)     {         _options = options.Value;         }      public SecurityHeadersBuilder AddDefaultPolicy()     {         AddFrameOptions();         AddConetntSecurityPolicy();         return this;     } } 

ConfigureServices method

public void ConfigureServices(IServiceCollection services) {             services.Configure<SecurityHeaderOptions>(Configuration.GetSection("SecurityHeaderOptions"));      services.AddScoped<SecurityHeadersBuilder>(provider =>             new SecurityHeadersBuilder(?????).AddDefaultPolicy()) } 

Questions
1> If i am explicitly passing options into constructor, do i need to register SecurityHeaderOptions with the container using service.Configure method?

2> Configuration.GetSection("SecurityHeaderOptions") can't return instance of IOptions<SecurityHeaderOptions> , instead it returns IConfigurationSection?

3>Either way, how do I retrieve and pass SecurityHeaderOptions into SecurityHeadersBuilder's constructor?

Answer 1

Using .NET Core 2 and not having a provider available (or caring to add it) in ConfigureServices I opted to go with something like this (using OP code as example):

public void ConfigureServices(IServiceCollection services) {     // secOpts available for use in ConfigureServices     var secOpts = Configuration         .GetSection("SecurityHeaderOptions")         .Get<SecurityHeaderOptions>();      ... } 

Answer 2

This is how I register options and inject into SecurityHeadersBuilder

public void ConfigureServices(IServiceCollection services) {     services.Configure<SecurityHeaderOptions>(Configuration.GetSection("SecurityHeaderOptions"));                 services.AddScoped<SecurityHeadersBuilder>(provider =>     {         var option = provider.GetService<IOptions<SecurityHeaderOptions>>();         return new SecurityHeadersBuilder(option)             .AddDefaultPolicy();     }); }