How to get IOptions in ConfigureServices method?

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?

Solution 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>();

    ...
}

Solution 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();
    });
}