ASP.NET Core 2 AddGithub OAuth extension

AuthenticationBuilderExtensions.cs

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Security.Claims;
using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authentication.OAuth;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Newtonsoft.Json.Linq;

namespace SampleMvc.Extensions
{
    public static class AuthenticationBuilderExtensions
    {
        public static AuthenticationBuilder AddGithub(this AuthenticationBuilder builder, Action<OAuthOptions> configureOptions)
        {
            builder
                .AddOAuth("Github", "GitHub", options =>
                {
                    options.CallbackPath = new PathString("/signin-github");
                    options.AuthorizationEndpoint = "https://github.com/login/oauth/authorize";
                    options.TokenEndpoint = "https://github.com/login/oauth/access_token";
                    options.UserInformationEndpoint = "https://api.github.com/user";
                    options.ClaimsIssuer = "OAuth2-Github";
                    options.SaveTokens = true;
                    // Retrieving user information is unique to each provider.
                    options.ClaimActions.MapJsonKey(ClaimTypes.NameIdentifier, "id");
                    options.ClaimActions.MapJsonKey(ClaimTypes.Name, "login");
                    options.ClaimActions.MapJsonKey("urn:github:name", "name");
                    options.ClaimActions.MapJsonKey(ClaimTypes.Email, "email", ClaimValueTypes.Email);
                    options.ClaimActions.MapJsonKey("urn:github:url", "url");
                    options.Events = new OAuthEvents
                    {
                        OnCreatingTicket = async context =>
                        {
                            // Get the GitHub user
                            var request = new HttpRequestMessage(HttpMethod.Get, context.Options.UserInformationEndpoint);
                            request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", context.AccessToken);
                            request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

                            var response = await context.Backchannel.SendAsync(request, context.HttpContext.RequestAborted);
                            response.EnsureSuccessStatusCode();

                            var user = JObject.Parse(await response.Content.ReadAsStringAsync());

                            context.RunClaimActions(user);
                        }
                    };
                    configureOptions?.Invoke(options);
                });
            return builder;
        }

    }
}