ValidationProxy

ValidationProxy is a library that allows injection of dynamic validation rules in methods. It is designed with Web API services in mind and focuses on simplicity.

Example usage

Having the following service:

publicinterfaceICalculatorService{publicintCalculateFactorial(intnumber);}publicclassCalculatorService:ICalculatorService{publicintCalculateFactorial(intnumber){if(number==1){return1;}returnnumber*CalculateFactorial(number-1);}}

Assume we want to prevent CalculateFactorial from being called with numbers equal or less than zero and numbers above 10. Using ValidationProxy, this is achieved as follows:

• Annotate the CalculateFactorial method.

publicconststringFactorialTooSmall="factorial-too-small";publicconststringFactorialTooLarge="factorial-too-large";[Validator(0,ValidationActions.FactorialTooLarge)][Validator(1,ValidationActions.FactorialTooSmall)]publicintCalculateFactorial(intnumber){if(number==1){return1;}returnnumber*CalculateFactorial(number-1);}

• Add the validation interceptor in the Web API configuration.

services.AddValidatorInterceptor();

• Configure ICalculatorService for interception.

services.AddProxiedScoped<ICalculatorService,CalculatorService>();

• Add validation actions

ActionRepository.AddValidationAction(ValidationActions.FactorialTooSmall, info =>{varargument=info.ArgumentByPosition(0).AsInt();if(argument<=0){thrownewArgumentException($"Cannot calculate factorial for {argument}");}});ActionRepository.AddValidationAction(ValidationActions.FactorialTooLarge, info =>{varargument=info.ArgumentByName("number").AsInt();if(argument>10){thrownewArgumentException($"Will not calculate factorial for {argument}");}});

Validation actions can be removed or added dynamically during the lifetime of the application.