An Example of the Manifest Model

This is a worked example of how the Manifest Model might be used to define a validator. The example model is specified using JSON, assuming a simple JSON mapping to/from the manifest model classes.

The object model to be validated

This example assumes that you wish to validate instances of the ShoppingBasket class below. By extension, we will be including instances of the other objects in our validation also.

public class ShoppingBasket
{
  public ICollection<BasketItem> Items { get; set; }
}

public class BasketItem
{
  public StoreProduct Product { get; set; }
  public int Quantity { get; set; }
  public Guid ItemId { get; set; }
}

public class StoreProduct
{
  public long Id { get; set; }
}

The validation rules to be applied

In this example (to keep it brief), we want to apply only three validation validation rules to each basket. we will use the BasketItem.ItemId property to identify the items.

• Every item in the basket must have a positive BasketItem.Quantity
• Every item in the basket must have a non-null BasketItem.Product
• Every BasketItem.Product for every item in the basket must have a positive StoreProduct.Id
  • But we do not process this rule if the BasketItem.Quantity was invalid
  • In a real-world validation, this might not be a simple check for a positive number, it could be a rule which performs a database query to verify that this is a real/supported product in our store. This is why we have specified a dependency, to avoid executing this 'expensive' rule if the quantity is invalid.

Sample Manifest Model JSON

This JSON uses two validation rules from the CSF.Validation.StandardRules package: NotNull and IntegerInRange. This JSON, converted to a manifest model using some simple JSON deserialisation, would represent the validation described above.

{
  "Children": {
    "Items": {
      "CollectionItemValue": {
        "IdentityMemberName": "ItemId",
        "Children": {
          "Quantity": {
            "Rules": [
              {
                "RuleTypeName": "CSF.Validation.Rules.IntegerInRange, CSF.Validation.StandardRules",
                "RulePropertyValues": {
                  "Min": 1
                }
              }
            ]
          },
          "Product": {
            "Rules": [
              {
                "RuleTypeName": "CSF.Validation.Rules.NotNull, CSF.Validation.StandardRules",
              }
            ],
            "Children": {
              "Id": {
                "Rules": [
                  {
                    "RuleTypeName": "CSF.Validation.Rules.IntegerInRange, CSF.Validation.StandardRules",
                    "RulePropertyValues": {
                      "Min": 1
                    },
                    "Dependencies": [
                      {
                        "AncestorLevels": 2,
                        "MemberName": "Quantity",
                        "RuleTypeName": "CSF.Validation.Rules.IntegerInRange, CSF.Validation.StandardRules"
                      }
                    ]
                  }
                ]
              }
            }
          }
        }
      }
    }
  }
}