Request Validation

Requirements

• Do Request Validation before execute
• Should be able to do simple validation like Required, MaxSize
• Also complex validation like Unique name
• Request.Error.Code will be "Invalid Arguments" see Evengrid
• Request.ArgumentErrors will include list of ArgumentError(ArgumentName, ErrorCode, ErrorDescription)
• Some Argument ErrorCodes will be common/shared, like Required, DoesNotExist, etc... But some will be specific to module. Like "Product name is not unique". So each module may have its ow list of ErrorCodes specifc to that module. Need to make sure it doesn't conflict with other modules.

For POC in StoreAdmin -> StoreModule

• Validate ProductCreateRequest

Id shouldn't be set

Product Name is required

Price > 0 and valid currency

Product Name must be unique in this Store

• Validate ProductUpdateRequest

Id is valid product Id

Reuse the rest of validation as ProductCreateRequest

• Validate ProductDeleteRequest

Id is valid

Possible Approaches

Approach 1

https://github.com/JeremySkinner/FluentValidation Need to check how unit testable Is it better then Data Annotations?

Approach 2

    StoreCreateCommand
{
		Execute()
		{
			   ValidateRequest
			   ExecuteInternal
		}   

		ValidateRequest()
		{
			ValidateDataAnnotations
                            ValidateCustom1
                            ValidateCustom2
                            ValidateCustom3
		}
   }

   
   IValidator  //May have dependencies on other services
   {
       Validate();
   }
		

   IRequestValidator
   {
      Validate();
   }


   DataAnnotationsRequestValidator : IRequestValidator
   {
      Validate();
   }

   SinglePropertyRequestValidator : IRequestValidator
   {
      DependentProperties
      TargetProperty
      Validate();
   }

   MultiPropertyRequestValidator : IRequestValidator
   {
      DependentProperties
      TargetProperties
      Validate();
   }
      
   RequestValidatorService
   {
       Validate(List of IRequestValidator);
   }
    
   ValidatorFactory
   {
       IValidator Create();  //Uses IOC COntainer
   }