The ReflectionProperty class
(PHP 5)
Introduction
The ReflectionProperty class reports information about classes properties.
Class synopsis
Properties
- name
-
Name of the property. Read-only, throws ReflectionException in attempt to write.
- class
-
Name of the class where the property is defined. Read-only, throws ReflectionException in attempt to write.
Table of Contents
- ReflectionProperty::__clone — Clone
- ReflectionProperty::__construct — Construct a ReflectionProperty object
- ReflectionProperty::export — Export
- ReflectionProperty::getDeclaringClass — Gets declaring class
- ReflectionProperty::getDocComment — Gets doc comment
- ReflectionProperty::getModifiers — Gets modifiers
- ReflectionProperty::getName — Gets property name
- ReflectionProperty::getValue — Gets value
- ReflectionProperty::isDefault — Checks if default value
- ReflectionProperty::isPrivate — Checks if property is private
- ReflectionProperty::isProtected — Checks if property is protected
- ReflectionProperty::isPublic — Checks if property is public
- ReflectionProperty::isStatic — Checks if property is static
- ReflectionProperty::setAccessible — Set property accessibility
- ReflectionProperty::setValue — Set property value
- ReflectionProperty::__toString — To string
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения, относящиеся к переменным и типам
- Введение
- Установка и настройка
- Предопределенные константы
- Примеры
- Расширение
- Класс Reflection
- Класс ReflectionClass
- Класс ReflectionZendExtension
- Класс ReflectionExtension
- Класс ReflectionFunction
- Класс ReflectionFunctionAbstract
- Класс ReflectionMethod
- Класс ReflectionObject
- Класс ReflectionParameter
- Класс ReflectionProperty
- ReflectionType
- ReflectionGenerator
- Интерфейс Reflector
- Класс ReflectionException
Коментарии
I think a more accurate explanation is this:
The Reflection classes are designed to reflect upon the source code of an application, not on any runtime information.
I think you misunderstand the ReflectionProperty constructor in your example above. The fact that it accepts an object as argument is just a convenience feature - you are actually inspecting the class of that object, not the object itself, so it's basically equivalent to:
<?php
// works fine
$Reflection = new ReflectionProperty(get_class($a), 'a');
// throws exception
$Reflection = new ReflectionProperty(get_class($a), 'foo');
?>
Getting the class of the object you're passing in is implied, since inspecting a defined property is the purpose of this class.
In your example, $a->foo is a dynamic member - it is not defined as a member of class, so there is no defining class reference, line number, default value, etc. - which means, there is nothing to reflect upon.
Clearly this very useful library could use some real documentation...
There is way to get property type without reflection.
Not very clear, but there is:
<?php
function getPropType(object $object, string $propName): string
{
try {
$object->{$propName} = new class {};
} catch (\TypeError $e) {
// @hint: question mark in type can be used to detect if property is nullable
if (preg_match('/of type \??(.*)$/', $e->getMessage(), $m)) {
return $m[1];
}
throw $e;
} catch (\Error $e) {
// property doesn't exist or is not public
throw $e;
}
throw new \TypeError(sprintf('Property %s of class %s has no type', $propName, $object::class));
// alternatively return 'mixed';
}
?>
note: in case you need access to private/protected properties its easy to change this to be embedded in any class:
<?php
trait PropertyTypeResolver
{
public function getPropType(string $propName): string
{
try {
$this->{$propName} = new class {};
} catch (\TypeError $e) {
// @hint: question mark in type can be used to detect if property is nullable
if (preg_match('/of type \??(.*)$/', $e->getMessage(), $m)) {
return $m[1];
}
throw $e;
} catch (\Error $e) {
// property doesn't exist
throw $e;
}
throw new \TypeError(sprintf('Property %s of class %s has no type', $propName, $this::class));
// alternatively return 'mixed';
}
}
?>