Custom Exception Classes

Custom Exceptions

Extend Exception (or any descendant) to create domain-specific exceptions with extra context, enabling precise catch blocks in calling code.

Example

<?php
// Base domain exception
class AppException extends RuntimeException {}

// Specific exceptions
class NotFoundException extends AppException {
    public function __construct(string $resource, int $id) {
        parent::__construct("{$resource} with ID {$id} not found", 404);
    }
}

class ValidationException extends AppException {
    public function __construct(private array $errors) {
        parent::__construct("Validation failed", 422);
    }

    public function getErrors(): array {
        return $this->errors;
    }
}

// Usage
throw new NotFoundException("User", 42);
throw new ValidationException(["email" => "Email is required"]);

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Pro Tip

Create a hierarchy of custom exceptions rooted at a single AppException — catch AppException to handle all domain errors in one place.

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