Payment Required

This library intend to add a simple interface to your API, if a client of a Software-as-a-Service (SaaS) has their payments in order.

A middleware component is added to the middleware pipeline, and is injected with a instance of an object that implements IPaymentRequiredValidator with your "business rules" validation.

The response of the API will be either the result of the service if everything is OK, or a ProblemDetails with the description of the exception.

Configuration

1- Create an class that implements IPaymentRequiredValidator

public sealed class NoPaymentIsRequiredValidator : IPaymentRequiredValidator
    {
        private readonly PaymentRequiredResponse _paymentRequiredResponse;
        public NoPaymentIsRequiredValidator()
        {
            this._paymentRequiredResponse = new NoPaymentIsRequiredResponseNullObject();
        }
        public bool IsPaymentRequired()
        {
            return _paymentRequiredResponse.IsPaymentRequired;
        }
        public PaymentRequiredResponse ValidatePaymentRequired(HttpContext context)
        {
			// implement your own business logic
			// ...
            return _paymentRequiredResponse;
        }
    }

2- Add IPaymentRequiredValidator to Dependency Injection Container

We need to inject IPaymentRequiredValidator, one of the PaymentRequiredMiddleware dependencies.

	// ... previous application configurations and dependencies
	builder.Services.AddScoped<IPaymentRequiredValidator, NoPaymentIsRequiredValidator>();
	// ... even more application configurations.

3- Add PaymentRequiredMiddleware to middleware pipeline

Add PaymentRequiredMiddleware into the pipeline, between UseAuthentication and UseAuthorization. You need to identify your "client" in order to verify if payment is due or not.

	app.UseAuthentication();

	app.UseMiddleware<PaymentRequiredMiddleware>(); 
	
	app.UseAuthorization();

Credits

• @masterzdran

Attribution

Payment method icons created by Freepik - Flaticon