codeenigma / entity-validation-examples

Drupal 8 Entity Validation API examples to accompany a blog post

Entity Validation Examples

This Drupal 8 module accompanies a Code Enigma blog post. It illustrates how to use the Drupal 8 Entity Validation API to add different validation constraints to the entity creation process.

Blog post: Introduction to Drupal 8 Entity Validation

The examples are kept short and avoid anything that is not related to the actual topic of entity validation.

Example 1: ArticleLimitConstraint

This example limits the creation of nodes of the type article to a specified number (2).

In a real-world scenario this limit would probably be configured using a configuration form, or specified with a config variable in settings.php.

The module does the following:

1. Defines a new constraint: ArticleLimitConstraint.

2. Defines a new constraint validator: ArticleLimitConstraintValidator

3. Attaches the constraint to entities of the type node using a hook_entity_type_alter implementation.

How to test

To test this functionality:

• Enable the module.
• Create 2 articles.
• Attempt to create a 3rd article and notice the error message.

Example 2

Coming soon.