Related
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a object having some protected property that I want to get and set. The object looks like
Fields_Form_Element_Location Object
(
[helper] => formText
[_allowEmpty:protected] => 1
[_autoInsertNotEmptyValidator:protected] => 1
[_belongsTo:protected] =>
[_description:protected] =>
[_disableLoadDefaultDecorators:protected] =>
[_errorMessages:protected] => Array
(
)
[_errors:protected] => Array
(
)
[_isErrorForced:protected] =>
[_label:protected] => Current City
[_value:protected] => 93399
[class] => field_container field_19 option_1 parent_1
)
I want to get value property of the object. When I try $obj->_value or $obj->value it generates error. I searched and found the solution to use PHP Reflection Class. It worked on my local but on server PHP version is 5.2.17 So I cannot use this function there. So any solution how to get such property?
Here's the really simple example (with no error checking) of how to use ReflectionClass:
function accessProtected($obj, $prop) {
$reflection = new ReflectionClass($obj);
$property = $reflection->getProperty($prop);
$property->setAccessible(true);
return $property->getValue($obj);
}
I know you said you were limited to 5.2, but that was 2 years ago, 5.5 is the oldest supported version and I'm hoping to help people with modern versions.
Object can be typecasted into (associative) array and the protected members have keys prefixed with chr(0).'*'.chr(0) (see #fardelian's comment here). Using this undocummented feature you can write an "exposer":
function getProtectedValue($obj, $name) {
$array = (array)$obj;
$prefix = chr(0).'*'.chr(0);
return $array[$prefix.$name];
}
Alternatively, you can parse the value from serialized string, where (it seems) protected members have the same prefix.
This works in PHP 5.2 without the overhead of ReflectionClass. However, there are reasons why some property is protected and hidden from client code. The reading or writing can make the data inconsistent or the author provides some other way to expose it in effort to make the interface as lean as possible. When there are reasons to read the protected property directly, the then-correct approach was to implement __get() magic method, so always check if there is any and see what it does. This counter intuitive lookup was finally solved in PHP 8.1 with readonly properties.
Since PHP 8.0, there also attributes metadata accessible by ReflectionClass, make sure to check them also before performing attempts to break into protected members. Attributes superseded "Annotations"1, so check them, too.
1: annotations are a very nasty surprise to client coders: they parse comments to add crazy fancy black-box useless confusing functionality, should not be used anymore, but they still exist
That's what "protected" is meant for, as the Visibility chapter explains:
Members declared protected can be accessed only within the class itself and by inherited and parent classes.
If you need to access the property from outside, pick one:
Don't declare it as protected, make it public instead
Write a couple of functions to get and set the value (getters and setters)
If you don't want to modify the original class (because it's a third-party library you don't want to mess) create a custom class that extends the original one:
class MyFields_Form_Element_Location extends Fields_Form_Element_Location{
}
... and add your getter/setter there.
If you want to tinker with a class without adding getters and setters....
PHP 7 adds a call($obj) method (faster than old bindTo) on closures allowing you to call a function so the $this variable will act just as it would within a class -with full permissions.
//test class with restricted properties
class test{
protected $bar="protected bar";
private $foo="private foo";
public function printProperties(){
echo $this->bar."::".$this->foo;
}
}
$testInstance=new test();
//we can change or read the restricted properties by doing this...
$change=function(){
$this->bar="I changed bar";
$this->foo="I changed foo";
};
$change->call($testInstance);
$testInstance->printProperties();
//outputs I changed bar::I changed foo in php 7.0
For PHP 7.4+, we can use an Arrow Function and the Closure::call to access private and protected members using just one small line:
PHP 7.4+
Retrieving protected/private members:
class Test {
protected $data = 'Protected variable!';
}
// Will output "Protected variable!"
echo (fn() => $this->data)->call(new Test);
Altering protected/private members:
class Test {
protected $data = 'Testing';
}
$test = new Test;
(fn() => $this->data = "New Data!")->call($test);
// Will output "New Data!"
echo (fn() => $this->data)->call($test);
Of course, we can use a normal Closure function if we want to alter/use multiple members:
class Test {
protected $data = 'Data!';
}
$test = new Test;
(function() {
$this->new_data = "New {$this->data}";
})->call($test);
// Will output "New Data!"
echo (fn() => $this->new_data)->call($test);
If you cannot modify the original class and extending it is not an option either, you can use the ReflectionProperty interface.
The phptoolcase library has a handy method for this:
$value = PtcHandyMan::getProperty($your_object , 'propertyName');
Static property from a singleton class:
$value = PtcHandyMan::getProperty('myCLassName', 'propertyName');
You can find the tool here: http://phptoolcase.com/guides/ptc-hm-guide.html
$a=json_encode((array)$obj);
$b=(array)json_decode(str_replace('\u0000*\u0000','',$a));
echo($b['value']);
What I like to do is declare every property that would be writable from outside as public. The properties that you want to be visible for the outside world but not writable you should declare as protected and write __get() magic method so you can read them. Example:
/**
* Class Test
*
* #property int $protected
*
*/
class Test
{
private const READABLE = ['protected'];
protected $protected = 1;
public $public = 2;
public function __get($property)
{
//if you want to read every protected or private
return $this->$property ?? null;
//if you want only some protected and private values to be readable
if (in_array($property, self::READABLE)) {
return $this->$property;
}
}
}
$test = new Test();
echo $test->protected; //outputs 1
echo $test->public; //outputs 2
$test->protected = 3; //outputs error - protected property
The best would be to have property declaration like:
public readonly $protected = 1; //only readable from the outside
public $public = 2; //readable and writable from the outside
but no such syntax exists yet(or... at least I don't know about it). P.S. you should declare the protected/private properties that will be readable in the Class DockBlock as shown, so you can autocomplete them, otherwise you will be able to access them, but your IDE won't recognize them on autocomplete when you are writing code.
I have a string containing the class name and I wish to get a constant and call a (static) method from that class.
<?php
$myclass = 'b'; // My class I wish to use
$x = new x($myclass); // Create an instance of x
$response = $x->runMethod(); // Call "runMethod" which calls my desired method
// This is my class I use to access the other classes
class x {
private $myclass = NULL;
public function __construct ( $myclass ) {
if(is_string($myclass)) {
// Assuming the input has a valid class name
$this->myclass = $myclass;
}
}
public function runMethod() {
// Get the selected constant here
print $this->myclass::CONSTANT;
// Call the selected method here
return $this->myclass::method('input string');
}
}
// These are my class(es) I want to access
abstract class a {
const CONSTANT = 'this is my constant';
public static function method ( $str ) {
return $str;
}
}
class b extends a {
const CONSTANT = 'this is my new constant';
public static function method ( $str ) {
return 'this is my method, and this is my string: '. $str;
}
}
?>
As I expected (more or less), using $variable::CONSTANT or $variable::method(); doesn't work.
Before asking what I have tried; I've tried so many things I basically forgot.
What's the best approach to do this? Thanks in advance.
To access the constant, use constant():
constant( $this->myClass.'::CONSTANT' );
Be advised: If you are working with namespaces, you need to specifically add your namespace to the string even if you call constant() from the same namespace!
For the call, you'll have to use call_user_func():
call_user_func( array( $this->myclass, 'method' ) );
However: this is all not very efficient, so you might want to take another look at your object hierarchy design. There might be a better way to achieve the desired result, using inheritance etc.
in php 7 you can use this code
echo 'my class name'::$b;
or
#Uncomment this lines if you're the input($className and $constName) is safe.
$reg = '/^[a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*$/';
if(preg_match($reg,$className) !== 1 || preg_match($reg,$constName) !== 1)
throw new \Exception('Oh, is it an attack?');
$value = eval("return $className::$constName;");
You can achieve it by setting a temporary variable. Not the most elegant way but it works.
public function runMethod() {
// Temporary variable
$myclass = $this->myclass;
// Get the selected constant here
print $myclass::CONSTANT;
// Call the selected method here
return $myclass::method('input string');
}
I guess it's to do with the ambiguity of the ::, at least that what the error message is hinting at (PHP Parse error: syntax error, unexpected T_PAAMAYIM_NEKUDOTAYIM)
Use call_user_func to call static method:
call_user_func(array($className, $methodName), $parameter);
Classes defined as abstract may not be instantiated, and any class that contains at least one abstract method must also be abstract. Methods defined as abstract simply declare the method's signature - they cannot define the implementation.
When inheriting from an abstract class, all methods marked abstract in the parent's class declaration must be defined by the child; additionally, these methods must be defined with the same (or a less restricted) visibility. For example, if the abstract method is defined as protected, the function implementation must be defined as either protected or public, but not private. Furthermore the signatures of the methods must match, i.e. the type hints and the number of required arguments must be the same. This also applies to constructors as of PHP 5.4. Before 5.4 constructor signatures could differ.
Refer to http://php.net/manual/en/language.oop5.abstract.php
This might just be tangential to the subject but, while searching for my own issue I found that the accepted answer pointed me in the right direction, so I wanted to share my problem & solution in case someone else might be stuck in a similar fashion.
I was using the PDO class and was building some error options from an ini config file. I needed them in an associative array in the form: PDO::OPTION_KEY => PDO::OPTION_VALUE, but it was of course failing because I was trying to build the array with just PDO::$key => PDO::$value.
The solution (inspired from the accepted answer):
$config['options'] += [constant('PDO::'.$key) => constant('PDO::'.$option)];
where everything works if you concatenate the class name and the Scope Resolution Operator as a string with the variable and get the constant value of the resulting string through the constant function (more here).
Thank you and I hope this helps someone else!