get_class_vars
(PHP 4, PHP 5)
get_class_vars — Get the default properties of the class
Description
array get_class_vars
( string
$class_name
)Get the default properties of the given class.
Parameters
-
class_name -
The class name
Return Values
Returns an associative array of declared properties visible from the
current scope, with their default value.
The resulting array elements are in the form of
varname => value.
In case of an error, it returns FALSE.
Changelog
| Version | Description |
|---|---|
| 5.0.3 | Depending on the scope, get_class_vars() will only return the properties that can be accessed from the current scope. |
| 5.0.2 | Calling get_class_vars() will now expose all the properties as an array, unlike previous behaviour where protected and private properties were prefixed with nul bytes. |
| 5.0.1 | Calling get_class_vars() will expose all properties, as when converting an object to a class. |
| 4.2.0 | Uninitialized class variables are now also reported by get_class_vars(). |
Examples
Example #1 get_class_vars() example
<?php
class myclass {
var $var1; // this has no default value...
var $var2 = "xyz";
var $var3 = 100;
private $var4; // PHP 5
// constructor
function myclass() {
// change some properties
$this->var1 = "foo";
$this->var2 = "bar";
return true;
}
}
$my_class = new myclass();
$class_vars = get_class_vars(get_class($my_class));
foreach ($class_vars as $name => $value) {
echo "$name : $value\n";
}
?>
The above example will output:
// Before PHP 4.2.0 var2 : xyz var3 : 100 // As of PHP 4.2.0 var1 : var2 : xyz var3 : 100
Example #2 get_class_vars() and scoping behaviour
<?php
function format($array)
{
return implode('|', array_keys($array)) . "\r\n";
}
class TestCase
{
public $a = 1;
protected $b = 2;
private $c = 3;
public static function expose()
{
echo format(get_class_vars(__CLASS__));
}
}
TestCase::expose();
echo format(get_class_vars('TestCase'));
?>
The above example will output:
// 5.0.0 a| * b| TestCase c a| * b| TestCase c // 5.0.1 - 5.0.2 a|b|c a|b|c // 5.0.3 + a|b|c a
See Also
- get_class_methods() - Gets the class methods' names
- get_object_vars() - Gets the properties of the given object
- PHP Руководство
- Функции по категориям
- Индекс функций
- Справочник функций
- Расширения, относящиеся к переменным и типам
- Функции работы с классами и объектами
- __autoload
- call_user_method_array
- call_user_method
- class_alias
- class_exists
- get_called_class
- get_class_methods
- get_class_vars
- get_class
- get_declared_classes
- get_declared_interfaces
- get_declared_traits
- get_object_vars
- get_parent_class
- interface_exists
- is_a
- is_subclass_of
- method_exists
- property_exists
- trait_exists
Коментарии
If you want to retrieve the class vars from within the class itself, use $this.
<?php
class Foo {
var $a;
var $b;
var $c;
var $d;
var $e;
function GetClassVars()
{
return array_keys(get_class_vars(get_class($this))); // $this
}
}
$Foo = new Foo;
$class_vars = $Foo->GetClassVars();
foreach ($class_vars as $cvar)
{
echo $cvar . "<br />\n";
}
?>
Produces, after PHP 4.2.0, the following:
a
b
c
d
e
in PHP5 to get all the vars (including private etc.) use:
$reflection = new ReflectionClass($class);
$defaults = $reflection->getdefaultProperties();
Contrary to multiple comments throughout the manual, get_class_vars() performed within a class can access any public, protected, and private members.
<?php
class Foo {
public $x;
protected $y;
private $z;
public function __sleep() {
return( get_class_vars( __CLASS__ ) );
}
}
?>
works fine (returns x, y, & z). However, given the same class as above,
<?php
print_r( get_class_vars( "Foo" ) );
?>
will NOT return x, y, & z. Instead it will only return the public members (in our case, z).
I wanted a simple ToString() function that was automatic and class independent. I wanted to dump it into any of several classes and get values quickly. I wanted to leave it there so I could customize it for each class, so an outside function wasn't suitable. I came up with this and thought it might be useful. Have fun!
<?php
function ToString () {
$s = "";
$s .= "<table>\n";
$s .= "<tr><td colspan=2><hr></td></tr>\n";
foreach (get_class_vars(get_class($this)) as $name => $value) {
$s .= "<tr><td>$name:</td><td>" . $this->$name . "</td></tr>\n";
}
$s .= "<tr><td colspan=2><hr></td></tr>\n";
$s .= "</table>\n";
return $s;
}
?>
If you assign a constant value using the self-scope by default to a variable, get_class_vars() will result in a FATAL error.
Example:
<?PHP
class Foo {
const Bar = "error";
public $Foo = self::Bar;
}
print_r(get_class_vars("Foo"));
?>
... but using "Foo::Bar" instead "self::Bar" will work ;)
This is one of the best php functions. Look at what you can do
class Object
{
var $updtFields;//keep track of affected values
function Object($record="") {
if (is_array($record))
{
$this->updtFields = array();
foreach(array_keys(get_class_vars(get_class($this))) as $k)
if (isset($record[$k]))
{
$this->$k = $record[$k];
$this->updtFields[] = $k;
}
}
}//end of arrayToObject
function toDebug($nl='<br>')
{
foreach(array_keys(get_class_vars(get_class($this))) as $k)
echo "$k = [" . $this->$k . "]{$nl}";
}//end of toDebug
}
Now you can do really cool things. If you have a form like
<form action="" method="post">
<input type="text" name="name" />
<input type="text" name="phone" />
<input type="submit" />
</form>
and you define your class like this
class Person extends Object{
var $name; //same same as in the form
var $phone;
}
when you submmit the form, you can get the data like
$person = new Person($_POST);
//everything in just one line,cool!! Also if you use pear db or adodb when you get data from the database you can do the same thing except use the $row that you get from the database. Remember to ask the result is associative mode.
This is my core Object for everthing I do and it works great.
There seems to be be a function to get constants missing , i.e. get_class_constants() ... so here is a simple function for you all. Hopefully Zend will include this in the next round as a native php call, without using reflection.
<?php
function GetClassConstants($sClassName) {
$oClass = new ReflectionClass($sClassName);
return $oClass->getConstants());
}
?>
So I wanted to get a list of the public parameters in a child class using a static function pre-5.3.0 (< 5.3.0). In 5.3.0+ you would use the new 'static' like you would 'self' to get the late binding.
<?php
class childClass extends parentClass
{
public $id;
public $name;
public static function getFields()
{
return self::_getFields(__CLASS__);
}
}
abstract class parentClass
{
public $idInParent;
public $nameInParent;
abstract public static function getFields();
final protected static function _getFields($className)
{
$rtn = array();
foreach (array_keys(get_class_vars($className)) as $var) {
$rtn[] = $var;
}
return $rtn;
}
}
var_dump(childClass::getFields());
?>
Results:
array(4) {
[0]=>
string(2) "id"
[1]=>
string(4) "name"
[2]=>
string(10) "idInParent"
[3]=>
string(12) "nameInParent"
}
If you need get the child protected/private vars ignoring the parent vars, use like this:
<?php
class childClass extends parentClass {
private $login;
private $password;
public function __set($key, $val) {
if ($key == 'password')
$this->$key = md5($val);
else
$this->$key = $val;
}
}
class parentClass {
public $name;
public $email;
function __construct() {
$reflection = new ReflectionClass($this);
$vars = array_keys($reflection->getdefaultProperties());
$reflection = new ReflectionClass(__CLASS__);
$parent_vars = array_keys($reflection->getdefaultProperties());
$my_child_vars = array();
foreach ($vars as $key) {
if (!in_array($key, $parent_vars)) {
$my_child_vars[] = $key;
}
}
print_r($my_child_vars);
}
}
$child_class = new childClass();
?>
All 3 of get_object_vars, get_class_vars and reflection getDefaultProperties will reveal the name of the array. For serialization I recommend:
<?php
$cName = get_class($this);
$varTemplate= get_class_vars($cName)
foreach ($varTemplate as $name => $defaultVal) {
$vars[$name] = $this->$name; // gets actual val.
}
?>
No scan the $vars and create serialization string how you wish.
This protects against erroneous prior deserializing in maintaining the integrity of the class template and ignoring unintended object properties.
If you need the variables before the class is included this function does not seem to work.Use a reflection class to get around this.
http://www.php.net/reflectionclass
I propse following for getting Public members, always:
<?PHP
if (!function_exists("get_public_class_vars")) {
function get_public_class_vars($class) {
return get_class_vars($class);
}
}
if (!function_exists("get_public_object_vars")) {
function get_public_object_vars($object) {
return get_object_vars($object);
}
}
?>
This is to mitigate the problem and a feature that get_object_vars($this) returns private members. Running it simply outside the scope will get the public.
Iterating public members only and their defaults are enormously useful in e.g. in serialization classes such as options where each public member is an serializable that is saved and loaded.
get_class_vars_assoc()
- Returns an associative array with name of (parent) class(es) as key(s) and corresponding class vars as sub-arrays. My boilerplate for some crude O/R mapping.
Note: vars re-defined in sub-classes are ignored.
<?php
class GrandClass {
public $grandVar;
public $in_grand_and_parent;
public $in_grand_and_child;
public static function load() {
print_r(self::get_class_vars_assoc());
}
protected static function get_class_vars_assoc() {
$called = get_called_class();
//echo "called: $called \n";
$classVars[$called] = array_keys(get_class_vars($called));
$parent = get_parent_class($called);
while ( $parent !== FALSE ) {
//echo "parent: $parent \n";
$classVars[$parent] = array_keys(get_class_vars($parent));
$classVars[$called] = array_diff($classVars[$called],
$classVars[$parent]);
if ( isset($prevParentVars) ) {
$prevParentVars = array_diff($prevParentVars,
$classVars[$parent]);
}
$prevParentVars = &$classVars[$parent];
$parent = get_parent_class($parent);
}
return $classVars;
}
}
class ParentClass extends GrandClass {
public $in_grand_and_parent;
public $parentVar;
public $in_parent_and_child;
}
class ChildClass extends ParentClass {
public $in_grand_and_child;
public $in_parent_and_child;
public $childVar;
}
ChildClass::load();
?>
Array
(
[ChildClass] => Array
(
[2] => childVar
)
[ParentClass] => Array
(
[1] => parentVar
[2] => in_parent_and_child
)
[GrandClass] => Array
(
[0] => grandVar
[1] => in_grand_and_parent
[2] => in_grand_and_child
)
)
I needed to get only the class static variables, leaving out instance variables.
<?php
function get_static_vars($class) {
$result = array();
foreach (get_class_vars($class) as $name => $default)
if (isset($class::$$name))
$result[$name] = $default;
return $result;
}
?>
That function returns only the public ones. The same pattern can be used inside a class, then it returns private and protected static variables, too:
<?php
static protected function get_static_vars($class = NULL) {
if (!isset($class)) $class = get_called_class();
$result = array();
foreach (get_class_vars($class) as $name => $default)
if (isset($class::$$name))
$result[$name] = $default;
return $result;
}
?>
<?php
class someClass {
public function toArray() {
$records = array();
foreach( $this as $key => $value ) {
$records[$key] = $value;
}
return $records;
}
}
?>