Validation Laravel Package

Getting Started

Minimal Setup

1. Installation:

   composer require respect/validation
   

   Add to composer.json if using Laravel's autoloader:

   "autoload": {
       "psr-4": {
           "App\\": "app/",
           "Respect\\Validation\\": "vendor/respect/validation/src/"
       }
   }
   

   Run composer dump-autoload.

2. First Use Case: Validate a user input in a Laravel controller:

   use Respect\Validation\Validator as v;
   
   public function store(Request $request) {
       $validator = v::stringType()->notEmpty()->validate($request->input('name'));
       if ($validator->isValid()) {
           // Proceed with logic
       } else {
           return response()->json(['error' => $validator->getFullMessage()], 422);
       }
   }
   

3. Key Entry Point: The Validator facade (v::) is the primary interface. Start with the official documentation for validator lists and patterns.

Implementation Patterns

1. Chaining Validators

Leverage fluent interfaces for complex rules:

v::numericVal()
    ->positive()
    ->between(1, 100)
    ->validate($input);

2. Nested Validation

Validate arrays/objects with dot notation:

v::key('user.address.zip', v::numericVal()->length(5))
    ->validate($data);

3. Dynamic Factories

Create validators based on runtime input:

v::factory(function ($input) {
    return v::key('confirm_password', v::equals($input['password']));
})
->assert($request->all());

4. Attribute Validation (PHP 8.0+)

Annotate DTOs for automatic validation:

use Respect\Validation\Validators as v;

class UserDto {
    #[v\Email] public string $email;
    #[v\Between(18, 120)] public int $age;
}

// Validate all annotated properties
v::attributes()->assert($userDto);

5. Short-Circuiting

Stop validation at first failure (optimization for dependent checks):

v::shortCircuit(
    v::key('country', v::countryCode()),
    v::factory(fn($input) => v::key('state', v::subdivisionCode($input['country'])))
)->assert($data);

6. Result-Based Workflows

Inspect validation failures granularly:

$result = v::email()->validate($input);
if ($result->hasFailed()) {
    foreach ($result->getMessages() as $message) {
        // Handle each error (e.g., log, translate)
    }
}

7. Integration with Laravel

• Form Requests:

  use Respect\Validation\Validator as v;
  
  public function rules() {
      return [
          'email' => v::email()->setMessage('Invalid email format'),
          'age'   => v::between(18, 120),
      ];
  }
  

• Service Layer:

  public function validateUser(UserRequest $request) {
      $validator = v::allOf(
          v::key('email', v::email()),
          v::key('password', v::length(8, 32))
      );
      $validator->assert($request->validated());
  }
  

8. Custom Validators

Extend for domain-specific rules:

use Respect\Validation\Validator as v;
use Respect\Validation\Rules\Validator;

class StrongPasswordValidator extends Validator {
    public function validate($input) {
        return preg_match('/^(?=.*[a-z])(?=.*[A-Z])(?=.*\d).+$/', $input);
    }
}

// Usage
v::newValidator()->setValidator(new StrongPasswordValidator())
    ->validate($password);

Gotchas and Tips

Pitfalls

1. PHP 8.5 Requirement: Respect/Validation 3.x requires PHP 8.5+. Use 2.x for older PHP versions.

   composer require respect/validation:^2.4
   

2. validate() vs isValid():

   • validate() returns a ResultQuery (for inspection).
   • isValid() returns a boolean (legacy alias).

   // Prefer:
   $result = v::email()->validate($input);
   if ($result->hasFailed()) { ... }
   
   // Avoid (deprecated):
   if (!v::email()->isValid($input)) { ... }
   

3. Strict Defaults:

   • Contains, In, StartsWith are strict by default (use notStrict() for loose checks).
   • Each rejects non-iterables (use IterableVal for arrays/objects).

4. Nested Paths: Deeply nested keys (e.g., user.address.city) may fail if intermediate keys are missing. Use KeyOptional or KeyExists:

   v::keyOptional('user.address.city', v::stringType());
   

5. Custom Messages:

   • Use templated() for dynamic messages:

     v::numericVal()->templated('{{subject}} must be a number between {{min}} and {{max}}')
         ->between(1, 100);
     

   • Placeholders like {{subject}} (not {{name}} as in v2).

6. Attribute Validation:

   • Only validates public properties. Use PropertyOptional for non-existent properties:

     #[v\PropertyOptional('metadata', v\arrayType())] public ?array $metadata;
     

7. Short-Circuiting:

   • Stops at the first failure. Use allOf() or anyOf() for parallel validation:

     v::allOf(
         v::key('email', v::email()),
         v::key('phone', v::phoneNumber())
     );
     

Debugging Tips

1. Inspect Results:

   $result = v::email()->validate($input);
   dd($result->getFullMessage()); // Full error tree
   dd($result->getMessages());    // Flat array of messages
   

2. Enable Debug Mode: Set RESPECT_VALIDATION_DEBUG=1 to see raw validation traces.

3. Validator Registry: Check registered validators with:

   \Respect\Validation\Validator::getRegistry()->getAll();
   

4. Symfony Translation: Integrate with Laravel’s translator:

   use Symfony\Contracts\Translation\TranslatorInterface;
   
   $validator = v::email()
       ->setTranslator($app->make(TranslatorInterface::class));
   

Performance Tips

1. Reuse Validators: Cache frequently used validators (e.g., in a service container):

   $emailValidator = v::email();
   // Reuse $emailValidator across requests.
   

2. Short-Circuit for Dependent Checks: Avoid validating unrelated fields when possible:

   v::shortCircuit(
       v::key('country', v::countryCode()),
       v::factory(fn($input) => v::key('state', v::subdivisionCode($input['country'])))
   );
   

3. Avoid allOf/anyOf Overhead: Use all() or any() for lightweight checks:

   v::all(v::numericVal())->validate([1, 2, 3]); // Faster than allOf()
   

Extension Points

1. Custom Validators:

   • Extend Validator for reusable rules.
   • Use #[Template] for custom error messages:

     #[Template('{{subject}} must be a palindrome')]
     class PalindromeValidator extends Validator {
         public function validate($input) {
             return $input === strrev($input);
         }
     }
     

2. Custom Formatters: Override NestedListStringFormatter for custom error output:

   use Respect\Validation\Exception\NestedListStringFormatter;
   
   class CustomFormatter extends NestedListStringFormatter {
       protected function formatMessage(string $message): string {
           return strtoupper($message);
       }
   }
   

3. PSR-11 Container: Register custom validators via a PSR-11 container:

   $container->set(StrongPasswordValidator::class, fn() => new StrongPasswordValidator());
   \Respect\Validation\Validator::setContainer($container);
   

4. Laravel Service Provider: Bind the validator to Laravel’s container:

   public function register() {
       $this->app->singleton(\Respect\Validation\Validator::class, function () {
           return \Respect\Validation\Validator::create();
       });
   }
   

Migration from v2 to v3

1. Key Changes:
   • Validator