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Entity API Overview
FreeWhen learning Drupal development, it won't be long before you encounter the word "entity" and the Entity API. But what are entities in Drupal? How can you use them to build your site? When should you use the Entity API?
This tutorial will explain Drupal's Entity system from a high level. We'll look at:
- The main problems the Entity system solves
- Key terms you should know
- Key concepts we'll explore as we dive into Drupal's Entity API
By the end of this tutorial you should be able to explain the problems that the Entity API solves, and when you should use it in your own code.
Drupal includes the Symfony Validator component, and provides an Entity Validation API to assist in validating the values of fields on an entity. By using the Entity Validation API you can ensure that you're validation logic is applied to Entity CRUD operations regardless of how they are triggered. Whether editing an Entity via a Form API form, or creating a new Entity via the REST API, the same validation code will be used.
Using the Entity Validation API in order to validate the value of a field on an entity requires:
- Defining (or choosing) a constraint plugin
- Defining (or choosing) a validation plugin
- Adding the constraint to the field definition
In this tutorial, we'll look at how this Validation API works and how it can be used in custom code to ensure our entities have properly constructed values. We'll look at how this validation works in Drupal core and how we can add our own additional constraints. We'll also see how to work with the error messages returned from the validator when our entity doesn't pass validation.
Containers are sandboxed applications that can be run anywhere, no matter the underlying host OS. Docker containers are quite different from VMs in a number of ways that need to be understood before we can use them to develop Drupal sites.
In this tutorial, we'll:
- Define a container
- Explain how a container is a more limited environment than a VM
Clear Drupal's Cache
FreeKnowing how to clear Drupal's cache is an important skill for any developer. You'll likely find yourself doing it frequently in order to get Drupal to register the changes you make to your code, or other updates you make via the UI. It is also a good first step to trouble shooting problems with your Drupal site: Clear the cache before you do any other debugging to ensure it's not just a bad cache entry.