Authentication via VK in asp.net core web api. How to implement correctly?

Question

OAuth

I am writing an application. The server part is a web api on asp.net core, and the client part is a vuejs application. My task is to implement a user login to the site through VKontakte.
The backend uses the AspNet.Security.OAuth.Vkontakte package .

ConfigureServices

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication()
        .AddVkontakte(builder =>
        {
            builder.ApiVersion = "5.130";
            builder.ClientId = Configuration["ClientId"];
            builder.ClientSecret = Configuration["SecureKey"];

            builder.AuthorizationEndpoint = "https://oauth.vk.com/authorize";
            builder.TokenEndpoint = "https://oauth.vk.com/access_token";

            builder.Scope.Add("friends");
            builder.Scope.Add("offline");
        });
    services.AddControllers();
    services.AddSwaggerGen(c =>
    {
        c.SwaggerDoc("v1", new OpenApiInfo { Title = "WeAgree", Version = "v1" });
    });
}

I don't understand how to properly implement the user authentication logic.
How to correctly pass the authentication request from the frontend to the server and how to tell the frontend that everything went well or vice versa?

Answer 1

Generate a jwt token on the server side.
Further, this vue token is hawked in local.storage and in the http interceptor constantly puts this token in the request. Handler on the bark, each request listens and checks the embedded token from the client for validity. Throws standard errors 400 and 401 if the token is not valid or has already timed out.
Everything is pretty standard.
For self-learning purposes, implement authentication with your api and your login password, without using the vk api. As soon as everything works, then connect VK api.