Validate your entities with symfony validator and entity validation api

Editor's Notes

• #2: Hello everyone, thanks for coming, this session is “Validate your entities with symfony validator and Entity Validation API”
• #3: I want to thank all the sponsors, because the conference wouldn't be possible without help from sponsors
• #6: I am software engineer at IbuildingsI work with Drupal since 2011, i am maintainer of different contributed modules: (Paragraphs React : a first integration between ReactJS and Paragraphs contrib module) (jQuery Touch Swipe: a module that implements a system that allow users to flags content in relation to touch events) swipe up..down.., it integrates with the flag contrib module (Paragraphs Wizard : a simple field formatter for paragraphs for generate a multistep wizard)
• #8: This session will not focus on all the complex structures behind the entity validation system (e.g.: Typed Data API), but on how you as a developer can leverage entity validation to improve your module or site's data integrity.
• #9: Input validation, also known as data validation, is the proper testing of any input supplied by a user or application. Input validation prevents improperly formed data from entering an information system. 
• #14: 1. Validates content on multiple levels, you’ll se what those levels are later 2. When it fails it returns a list of violations, if succeeds you get an empty list 3. Happens automatically in entity form validation, so you don’t need to call other methods if you are submitting an entity form
• #16: JSR 303 (Bean Validation) Simply put it provides an easy way of ensuring that the properties of your objects have the right values in them. This document describes each aspect of the bean validation specification in a separate chapter. One should remember that the specification is a consistent whole. Chapter 2, Constraint Definition describes how constraints are defined. Chapter 3, Constraint declaration and validation process describes how a JavaBean class is decorated with annotations to describe constraints. Chapter 4, Validation APIs describes how to programmatically validate a JavaBean. Chapter 5, Constraint metadata request APIs describes how the metadata query API works.
• #17: This new validation API has been implemented based on the Symfony validator.
• #19: An important fact, is that you always get the list of violations even if it’s empty.
• #20: So, first, you call ->validate() on your entity, then you can call $violations->count() and if the count is higher than zero you know you have a problem. Implements also the \iteratoraggregate so you can simply loop over the violations with a foreach
• #21: To get a list of Entity level violations we can use the getEntityViolations() method and loop through all of them. Once we have our individual ConstraintViolationInterface instances, we can inspect them for what went wrong. For instance, we can get the error message with getMessage(), the property path that failed with getPropertyPath() and the invalid value with getInvalidValue(), among other useful things.
• #30: (Src/Plugin/Validation/Constraint, all below this path will be discoverable by drupal) * While core does not prefix constraint plugins, modules have to prefix them * with the module name in order to avoid any naming conflicts; for example, a * "profile" module would have to prefix any constraints with "Profile".
• #31: No t() needed You can use placeholders
• #32: It’s the same of the Constraint, Extends the Constraint Class, it allows to pass an array of fields to the validator. /** * Provides a base class for constraints validating multiple fields. * * The constraint must be defined on entity-level; i.e., added to the entity * type. * * @see \Drupal\Core\Entity\EntityType::addConstraint */
• #34: Inside validate, you don't need to return a value. Instead, you add violations to the validator's context property and a value will be considered valid if it causes no violations. The buildViolation() method takes the error message as its argument and returns an instance of ConstraintViolationBuilder. The addViolation() method call finally adds the violation to the context using messages coming from your constraint. For Dependency Injection you can implement ContainerInjectionInterface.
• #35: The methods that you’ll use the most are “addViolation” and “buildViolation”, for instance when you need to return a dynamic error message (set a minimum and a maximum of a range….)
• #36: For instance when validating a node, the context will always be that node, because the validate method is executed on the $node object, if you call validate on a single field, then the context will be that field.
• #39: The field name vanish from the property path because it becomes the context that i’ve mentioned before.
• #42: Entity level If you are creating a new ContentEntity type You can set the constraints property into the constraints @ContentEntityType Constraints = {“commentname” = {}}
• #43: We can provide our own implementation of Hook_entity_type_alter And then ->addConstraint And the options, so for instance my constraint has got an option called “bad” and i want it to have the value 1 For instance you can have a range constraint here and set minimum and maximum value
• #44: This is how drupal defines the uri baseFieldDefinition of the file entity in the core, BasefieldDefinition has the addConstraint method too
• #45: Always search for already existing validators rather than always create your own validators
• #46: This is the code of paragraphs that checks that has an allowed paragraph type
• #47: Examples of fieldtype are for instance you have entityreference, optionlist, address (this is an example of address module), most of the time you’ll apply validators at entity level but if you create your own fieldtype you might need this. A correct approach for the field type is to use the ValidatoinConstraintManager and return a list of constraints, you can istantiate them using the ->create method of the ConstraintManager and return them in an array. /** * Constraint plugin manager. * * Manages validation constraints based upon * \Symfony\Component\Validator\Constraint, whereas Symfony constraints are * added in manually during construction. Constraint options are passed on as * plugin configuration during plugin instantiation. * You can also use the getDefinitionsByType method of the ConstraintManager to get Constraints by type, so for instance if i’m creating an integer field using validationconstraintmanager i can get all the Constraints that can be applied to an integer field. * Complex data constraint.** Validates properties of complex data structures.
• #48: This is from EntityReferenceItem.php (a @FieldType Plugin) , from the entity reference module in the core You are already defining the property and you can call directly addConstraint on the property.
• #51: This is the reason why i've decided to perform this talk, i was trying to validate a node with a paragraph field
• #53: Core Validation tests
• #54: My Advice is to use this, defining constraint in the data architeture is very important so your application won’t blow up just because someone entered wrong data. Any questions ?, thank you very much for listening.