Integrity Checks - smbc-digital/form-builder Wiki

Integrity checks are small units of code that validate features or components defined in the JSON DSL.

When a form is loaded, before it's cached (if caching is turned on), the integrity of the form is checked to ensure it's in a valid state.

Form Schema Integrity Validator

Validation happens in a IFormSchemaIntegrityValidator.Validate this should be called from FormSchemaFactory.

A list of IFormSchemaIntegrityCheck is injected into the IFormSchemaIntegrityValidator.

The default implementation of IFormSchemaIntegrityValidator simply aggregates any failure messages and throws a new ApplicationException containing all recorded failures.

Creating an Integrity Check

If a new component or element is being added to the DSL that contains rules custom logic an integrity check should be created to check these rules.

You can create an Integrity Check for the whole form if required, perhaps when corresponding/dependent elements are on different pages. Or if it's just a specific behaviour, or just need to validate a stand-a-lone element.

  1. IFormSchemaIntegrityCheck -> Form wide validation
  2. IBehaviourSchemaIntegrityCheck -> For validating a new behaviour of a page
  3. IElementSchemaIntegrityCheck -> For validating just the element

To create a new Integrity check you must implement the I{Form/Behaviour/Element}SchemaIntegrityCheck.Validate methods.


    public interface IFormSchemaIntegrityCheck
        IntegrityCheckResult Validate(FormSchema schema);
        Task<IntegrityCheckResult> ValidateAsync(FormSchema schema);

the Validate methods return an IntegrityCheckResult object, this contains an bool IsValid flag and a list Messages of reasons for failure.

Registering a new Integrity Check

Registering an integrity check using dependency injects as below.

services.AddSingleton<IFormSchemaIntegrityCheck, MyCustomIntegrityCheck>();

services.AddSingleton<IBehaviourSchemaIntegrityCheck, MyBehaviourCheck>();

services.AddSingleton<IElementSchemaIntegrityCheck, MyElementCheck>();

This can be done either directly in startup.cs or preferrably in the convenience method AddSchemaIntegrityValidation in /Utils/Startup/ ServiceCollectionsExtensions.cs