.NET Core Web API key

Question

I am developing an application that users can authenticate via username and password and we provide a JWT token that then gets validated on the server.

One thing I would like to add is the ability to have a special API Key (guid) that the users can use when integrating with this application instead of using a username and password.

I am unsure how to do this since the authentication part seems to be a bit of a black box (using Aspnet Identity).

Here is some of my code for the authentication setup.

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    // Add framework services.
    services.AddDbContext<OmbiContext>(options =>
        options.UseSqlite("Data Source=Ombi.db"));

    services.AddIdentity<OmbiUser, IdentityRole>()
        .AddEntityFrameworkStores<OmbiContext>()
        .AddDefaultTokenProviders();

    services.Configure<IdentityOptions>(options =>
    {
        options.Password.RequireDigit = false;
        options.Password.RequiredLength = 1;
        options.Password.RequireLowercase = false;
        options.Password.RequireNonAlphanumeric = false;
        options.Password.RequireUppercase = false;
    });
}

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IMemoryCache cache)
{
    var tokenOptions = (IOptions<TokenAuthentication>)app.ApplicationServices.GetService(
        typeof(IOptions<TokenAuthentication>));

    var ctx = (IOmbiContext)app.ApplicationServices.GetService(typeof(IOmbiContext));

    var tokenValidationParameters = new TokenValidationParameters
    {

        ValidateIssuerSigningKey = true,
        IssuerSigningKey = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(tokenOptions.Value.SecretKey)),

        RequireExpirationTime = true,
        ValidateLifetime = true,
        ValidAudience = "Ombi",
        ValidIssuer = "Ombi",
        ClockSkew = TimeSpan.Zero
    };

    app.UseJwtBearerAuthentication(new JwtBearerOptions()
    {
        Audience = "Ombi",
        AutomaticAuthenticate = true,
        TokenValidationParameters =  tokenValidationParameters,

    });
 //....
}

The above code works when having the [Authorized] attributes on controllers and checking for the roles and such.

Anyone have any idea how I can pass some sort of Api-Key header on all requests containing this special API Key for it to pass the [Authorized] attributes? (The key is stored in the database.)

Answer 1

This is what I did in the end:

 public static void ApiKeyMiddlewear(this IApplicationBuilder app, IServiceProvider serviceProvider)
    {
        app.Use(async (context, next) =>
        {
            if (context.Request.Path.StartsWithSegments(new PathString("/api")))
            {
                // Let's check if this is an API Call
                if (context.Request.Headers["ApiKey"].Any())
                {
                    // validate the supplied API key
                    // Validate it
                    var headerKey = context.Request.Headers["ApiKey"].FirstOrDefault();
                    await ValidateApiKey(serviceProvider, context, next, headerKey);
                }
                else if (context.Request.Query.ContainsKey("apikey"))
                {
                    if (context.Request.Query.TryGetValue("apikey", out var queryKey))
                    {
                        await ValidateApiKey(serviceProvider, context, next, queryKey);
                    }
                }
                else
                {
                    await next();
                }
            }
            else
            {
                await next();
            }
        });
    }

    private static async Task ValidateApiKey(IServiceProvider serviceProvider, HttpContext context, Func<Task> next, string key)
    {
        // validate it here
        var valid = false;
        if (!valid)
        {
            context.Response.StatusCode = (int)HttpStatusCode.Unauthorized;
            await context.Response.WriteAsync("Invalid API Key");
        }
        else
        {
            var identity = new GenericIdentity("API");
            var principal = new GenericPrincipal(identity, new[] { "Admin", "ApiUser" });
            context.User = principal;
            await next();
        }
    }

This has changed quite a bit since I answered the original question (Answer is still valid). But you can read about this here: https://tidusjar.github.io/2019/03/25/net-core-jwt-api-key/

Answer 2

There is a nice article on using api keys in header requests on this link: http://www.mithunvp.com/write-custom-asp-net-core-middleware-web-api/

To summarise, in ASP.NET Core , you can use Middleware to control the http pipeline configuration. Middleware effectively replaces HttpHandlers, which were used in ealier versions of asp.net MVC.