Effective Error Handling in PHP Applications

Proper error handling is crucial for building robust PHP applications. PHP offers several mechanisms to handle errors and exceptions gracefully.

Error Reporting Configuration

// Development environment
error_reporting(E_ALL);
ini_set('display_errors', 1);

// Production environment
error_reporting(E_ALL & ~E_DEPRECATED & ~E_STRICT);
ini_set('display_errors', 0);
ini_set('log_errors', 1);
ini_set('error_log', '/path/to/php-errors.log');

Exception Handling

PHP uses try-catch blocks for exception handling:

try {
    $file = fopen("nonexistent.txt", "r");
} catch (Throwable $e) {
    error_log("File error: " . $e->getMessage());
    echo "An error occurred. Please try again later.";
}

Custom Exception Classes

class ValidationException extends InvalidArgumentException {
    public function __construct(
        public readonly array $errors,
        string $message = "Validation failed"
    ) {
        parent::__construct($message);
    }
}

try {
    throw new ValidationException(['email' => 'Invalid format']);
} catch (ValidationException $e) {
    foreach ($e->errors as $field => $error) {
        echo "$field: $error\n";
    }
}

Error Handling Best Practices

• Log all errors in production
• Create custom exception classes for domain-specific errors
• Use finally blocks for cleanup operations
• Implement a global exception handler
• Convert errors to exceptions with set_error_handler()

Global Exception Handler

set_exception_handler(function (Throwable $e) {
    error_log("Uncaught exception: " . $e->getMessage());
    http_response_code(500);
    if (ENVIRONMENT === 'development') {
        echo "Error: " . $e->getMessage();
    } else {
        echo "An unexpected error occurred";
    }
});

Implementing these error handling strategies will make your application more reliable and easier to debug.