If I declared a class in a controller and want to use it in a model without passing the class' pointer, how can I redeclare that class without the "Fatal error: Class already declared"? If I use the get_declared_classes() function, I see that the class is declared, but how can I get the pointer to that class so that I can use it in the model?
Basically, how can I use a class that's been declared but with no pointer.
Any help would be greatly appreciated.
Thanks in advance!
EDIT: Maybe the word "pointer" was misused. Here's some code
// Controller...one file
$class = new Class();
$model = $this->load_model('example.php');
$model->dosomething();
// Model...example.php
function dosomething() {
// I want to access the class here. Is it only possible to do this by
// passing a $class parameter to the function or can I do it without
// passing it as a variable?
}
I think you're mixing terminology. There's no concept of a pointer anywhere in PHP. References are similar concepts, but that's another topic.
What I think you're trying to do, is use a variable to indicate the class in the model. So, you can use a string. So let's say you want to tell the model to use class Foo, you could inject the class name into the model:
$model = new Model('foo');
Then, inside the constructor:
public function __construct($class) {
$this->className = $class;
}
Then, when you want to use it, just call new:
$class = $this->className;
$obj = new $class();
But note that it has nothing to do with object scope. So you could do it anywhere:
$class = 'Foo';
$obj = new $class;
Related
I have a class like this:
class MyClass extends CActiveRecord {
public function getSelectedIds()
{
return '';
}
public function setSelectedIds($value)
{
$this->selectedIds = $value;
}
}
This kind of produces weird results:
$object = new MyClass();
$object->selectedIds = 'test';
//Line below shows 'test'
echo $object->selectedIds;
//line below show ''
echo $object->getSelectedIds();
Now my question is why doesn't it break/show some error? Why $this->selectedIds = $value; works within the method even though selectedIds is not defined within the class?
Edit:
Basically I understand that $object->selectedIds = 'xx' resolves to setSelectedIds($xx).
But what does $this->selectedIds == 'xx' resolve to? To itself? And if so why not loop into infinity?
And why $object->selectedIds != $object->getSelectedIds() if $object->selectedIds should resolve to $object->getSelectedIds()...
Why $this->selectedIds = $value; works within the method even though selectedIds is not defined within the class?
You can freely add properties to objects at any time without previously having declared them.
$o = new stdClass;
$o->foo = 'bar';
They'll be created as plain public properties. It's possible that setSelectedIds isn't even called and you're just setting the property on the object straight (don't know if or how CActiveRecord defines __set).
Because:
$object->selectedIds
automatically resolves as function call, either getSelectedIds or setSelectedIds.
This concept is called Virtual Attributes and is achieved via custom implementation of __get and __set. Have a look at: Yii 1.1: Understanding Virtual Attributes and get/set methods
I have a class file: we'll call it class.php. The functionality of that is to grab info from an ini file (yeah, I posted the question about security and was given the great suggestion to use either a config file or an ini file to hold the DB information).
Essentially, my class is this:
<?php
class myClass
{
public function getAttached()
{
$file = "../../myFile.ini";
if (!$settings = parse_ini_file($file, TRUE)) throw new exception('Unable to open ' . $file . '.');
$hoost = $settings['mysqli']['default_host'];
$useer = $settings['mysqli']['default_user'];
$pazz = $settings['mysqli']['default_pw'];
$dbs = $settings['mysqli']['default_db'];
$con = mysqli_connect($hoost ,$useer, $pazz, $dbs);
return $con;
}
}
$obj = new myClass();
$obj->getAttached();
$vals = $obj->getAttached();
//echo $vals; //didn't know if I should echo this or not.
?>
I want to call this in my somePage.php file to make my "mysqli" connection and go from there...
I tried this:
require_once('class.php');
getAttached();
Obviously that didn't work (I knew it wouldn't but - I did it anyway just to see if "maybe"), so - how do I call that function from my class file in the regular php page?
Any thoughts would be appreciated.
Thanks in advance.
You need to make an instance of the class before calling the functions as they're not static.
require_once('class.php');
$myClass = new myClass();
$myClass-> getAttached();
or, like I said above you could make the function static.
public static function myFunction() {
//etc...
}
Then to call it you would use:
require_once('class.php');
myClass::getAttached();
You have to instanciate your class first, the same way you did it in you class.php file:
$myclass = new myClass();
$myClass->getAttached();
Note that if your method can be used without any relation with your class, you could make it static:
public static function getAttached() {
// ...
}
And use it without having to instanciate your class:
myClass::getAttached();
Your getAttached() method within the myClass ,create the instance for the class and call
the function
$call = new myClass();
$call->getAttached();
Given answers are correct, but if you keep your class file as you posted, you have object already in $obj so there is no need to make new one. If it is just temporary you can ignore my post.
One more thing:
$obj->getAttached(); // this line is not needed, as you call this function in next line
$vals = $obj->getAttached();
I have a class like the following:
class game {
public $db;
public $check;
public $lang;
public function __construct() {
$this->check = new check();
$this->lang = DEFAULT_LANG;
if (isset($_GET['lang']) && !$this->check->isEmpty($_GET['lang']))
$this->lang = $_GET['lang'];
}
}
As you can see I have a public variable $lang that is also defined via the contructor.
The proble is that I want to access the result of this variable from other classes that are not directly related to this class, since I don't want to redeclare it for each different class.
So for example how can I call the result of that variable from another class, lets call it class Check ?
if you mark the public $lang; as static:
public static $lang;
you can access it via game::$lang;
if not static, you need to make an instance of game and directly access it:
$game = new game;
$game->lang;
static call inside of (current) class:
self::$lang;
late static bound call (to inherited static variable):
static::$lang;
call from child class to parent:
parent::$lang;
normal call inside of an instance (instance is when you use new Obj();):
$this->lang;
BTW:
variables defined by define('DEFAULT_LANG', 'en_EN'); are GLOBAL scope, mean, can access everywhere!
<?php
define('TEST', 'xxx');
class game {
public function __construct() {
echo TEST;
}
}
//prints 'xxx'
new game;
you can make it static variable, so you will be able to call it anytime anywhere, the diff is that instead of
$this->lang;
when editing it(Works inside class game only) you do :
self::$lang;
and when you call/edit it (Works everywhere) from anther class you do :
game::$lang
the idea of static class is that its exist only in one instance, so only one $lang exist in your program. but there is no need to load the whole class to get acsess to it.
How can I call the result of that variable from another class, lets call it class Check?
A variable doesn't have a result. If you mean to retrieve the state of that variable on a specific object $obj of class game then you can simply do:
$obj->lang
On a side note if $lang is publicly only read only you should protect it by defining it private or protected and create a getter method instead.
If you mean that you want to use the same variable name in another class I'd suggest you to consider inheritance:
class Check extends game { /* now Check has $lang */ }
but the variable of the two objects will be different.
Since the property is public, you can access it from outside the class as $objInstance->property. It doesn't matter if you're calling it from a function, procedural script, in another object. As long as you have the instance, you can call it's public property. Ex:
function foo($c) {
echo $c->lang;
}
foo($check);
Also, some advice on working with objects and such: It's considered better code if you don't create instances of objects in the other objects, but rather pass them in someway (either a setter method or through the constructor). This keeps the classes loosely coupled and results in code that is more reusable and easier to test. So:
class Game
{
...
public function __construct($check, $defaultLang, $get) {
$this->check = $check;
$this->lang = $defaultLang;
if (isset($get['lang']) && !$this->check->isEmpty($get['lang']))
$this->lang = $get['lang'];
}
...
$game = new Game(new Check(), DEFAULT_LANG, $_GET);
echo $game->check;
The first half of this article is an accessible explanation of what is known as Dependency Injection.
I am developing on Symfony2 and I need to call a method on a class, both known only at runtime.
I have already successfully used variable functions and call_user_func in the project, but this time they give me problems...
My code looks like this
namespace MyBundleNamespace;
use MyBundle\Some\Class;
class MyClass
{
public static function myFunction() { ... }
}
and in some other file I need to do this
MyClass::myFunction();
but dynamically, so I tried both
$class = "MyClass";
$method = "myFunction";
$class::$method();
and
$class = "MyClass";
$method = "myFunction";
call_user_func("$class::$method");
But I get a class MyClass not found error. Of course the class is included correctly with use and if I call MyClass::myFunction() just like that it works.
I also tried to trigger the autoloader manually like suggested in this question answer comment, but it did not work. Also, class_exists returned false.
What am I missing? Any ideas?
Thanks!
You're missing the namespace:
$class = '\\MyBundleNamespace\\MyClass';
$method = 'myFunction';
Both calls should work:
call_user_func("$class::$method");
call_user_func(array($class, $method));
So I have this class:
class A{
public function do_a(){ return 'a_done';};
public function do_b(){ return 'b_done';};
}
So I require the php file and create an instance of the class:
require_once("A_class.php");
$System = new A();
require_once("user_calls.php"); //here I import the user file with the function calls.
user_calls.php contents:
echo 'this was the result of '.$System->do_a();
echo 'this was the result of '.$System->do_b();
So, that does work, but I don't want the user to have to use $System->do_a();, but only do_a();.
Any solutions?
EDIT: I also want to limit the functions the user could call in the user_calls.php file, to basic native php functions and those in class A.
DISCLAIMER: While this code works, and does what you requested, that doesn't mean that I advocate coding like this. It's very hard to follow for other developers (and maybe even you in the future...), and it also makes use of eval(), which is almost always A Bad Thing(tm). That said, here you go:
<?php
class A {
public function do_a() {
return __METHOD__;
}
public function do_b() {
return __METHOD__;
}
}
$aRef = new ReflectionClass('A');
$aPublicMethods = $aRef->getMethods(ReflectionMethod::IS_PUBLIC);
foreach ($aPublicMethods as $method) {
$php = <<<PHP
function {$method->name}() {
global \$System;
return \$System->{$method->name}();
}
PHP;
eval($php);
}
$System = new A();
echo 'this was the result of ' . do_a();
echo 'this was the result of ' . do_b();
Please also note that if your methods use arguments, things get even more hairy. Also, if you name any of your methods the same as a function in the global namespace (ex. substr()), this will attempt to redefine them, and you'll probably get a Fatal Error.
Methods of a class are either instance methods (they act on a particular instance of a class defined by $this) or they are class methods (They aren't tied to any one particular instance of a class, but provide services that fall within the remit of the class.
An instance method is defined as follows:
public function foo()
{
}
whereas a class method is defined with the STATIC keyword.
static public function bar()
{
}
In the instance method you can use $this to get access to the state of the instance on which the method was called. This is not available in the class method because it's not tied to any one instance. It can access other members of the class (provided they're not tied to an instance) with the self keyword though.
Instance methods are called as follows:
$a = new ObjType ()
$output = $a -> foo ();
Class methods are called as follows:
$output = ObjType::bar ();
No matter which approach you use you either have to provide an instance (for instance methods) or a class (for class methods) to call the method. Calling just foo() or bar() will not work.
You'll have to use a closure. Note that it's calling directly from the class definition, not the object:
class test {
function method() {
echo 'method was called';
}
}
$method = function(){call_user_func('test::method');};
$method();
$method();
$method();
//output:
//method was calledmethod was calledmethod was called
To call the method from the object, rather than the class, you'll have to pass the object into the closure:
class test {
var $count = 0;
function method() {
$this->count++;
echo $this->count . "|<br />";
}
}
$obj = new test;
$obj2 = new test;
$method = function($object){call_user_func(array($object, 'method'));};
$method($obj);
$method($obj);
$method($obj);
$method($obj2);
//output:
//1|
//2|
//3|
//1|
But that's not any prettier or simpler, is it?
If you don't want to clutter up your page, just name the object something short:
$pco = new page_controller_object_with_a_long_name_that_is_annoying;
$pco->do_a();
$pco->do_b();
//etc.
Moving it outside the class as suggested by #LucM sounds the easiest way.