AspNet.Security.ApiKey.Providers

API Key authentication middleware for ASP.NET Core.

Getting started

Grab the package from NuGet, which will install all dependencies.

Install-Package AspNet.Security.ApiKey.Providers

Usage

First add this authentication type to your pipeline:

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(options =>
    {
        options.DefaultScheme = ApiKeyDefaults.AuthenticationScheme;
    })
    .AddApiKey();
}

And enable authentication in your app:

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
{
    app.UseAuthentication();
}

You must then wire up your custom delegates to handle validation of incoming keys, as well as things like handling of errors during the authentication process:

options.Events = new ApiKeyEvents
{
    // Optional
    OnAuthenticationFailed = context =>
    {
        Trace.TraceError(context.Exception.Message);

        return Task.CompletedTask;
    },
    OnApiKeyValidated = context =>
    {
        if (context.ApiKey == "123")
        {
            // Build and set the context.Principal if you wish to attach an identity to your incoming request.
            context.Principal = new ClaimsPrincipal();

            // Mark success if you are happy the API key in the request is valid.
            context.Success();
        }

        return Task.CompletedTask;
    }
};

Customising Header Values

The format of the expected header containing the API key is completely customisable. By default, it expects a header in the following format:

Authorization: ApiKey {key}

If you wish to override this format, override the default values when configuring your ApiKeyOptions. For example:

// Authorization: MyType {key}

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(options =>
    {
        options.DefaultScheme = ApiKeyDefaults.AuthenticationScheme;
    })
    .AddApiKey(options =>
    {
        options.Header = "Authorization";
        options.HeaderKey = "MyType";
    });
}

// X-API-KEY: {key}

public void ConfigureServices(IServiceCollection services)
{
    services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = ApiKeyDefaults.AuthenticationScheme;
        options.DefaultChallengeScheme = ApiKeyDefaults.AuthenticationScheme;
    })
    .AddApiKey(options =>
    {
        options.Header = "X-API-KEY";
        options.HeaderKey = String.Empty;
    });
}

Custom Status Codes

If you wish to challenge the authentication result, you can set up a delegate to do this. For example, if you wish to return a different status code (e.g. a client's subscription has expired) you could check the reason for failure and change the code as appropriate:

options.Events = new ApiKeyEvents
{
    OnApiKeyValidated = context =>
    {
        if (context.ApiKey == "123")
        {
            context.Principal = new ClaimsPrincipal();

            context.Success();
        }
        else if (context.ApiKey == "789")
        {
            throw new NotSupportedException("You must upgrade.");
        }

        return Task.CompletedTask;
    },
    OnChallenge = context =>
    {
        if (context.AuthenticateFailure is NotSupportedException)
        {
            context.StatusCode = HttpStatusCode.UpgradeRequired;
        }

        return Task.CompletedTask;
    }
};

Advanced Usage

You can override the parsing of headers by wiring up an OnMessageReceived delegate. If you set an API key here then the parsing of the headers will be skipped - this may aid with things like testing.

options.Events = new ApiKeyEvents
{
    OnMessageReceived = context =>
    {
        context.ApiKey = "123";

        return Task.CompletedTask;
    }
};

You can use the ASP.NET Core IConfigureOptions<T> and IPostConfigureOptions<T> interfaces to help you set up your options as appropriate. Simply add these to your services and let ASP.NET Core take care of the rest:

public void ConfigureServices(IServiceCollection services)
{
    services.TryAddEnumerable(ServiceDescriptor.Singleton<IConfigureOptions<ApiKeyOptions>, MyConfigureOptions>());
    services.TryAddEnumerable(ServiceDescriptor.Singleton<IPostConfigureOptions<ApiKeyOptions>, MyPostConfigureOptions>());
}