I was wondering if it's possible to create a function and pass it a class name. The function then checks if an instance of the class currently exists, if it does not it create an instance of the class. Furthermore if possible make that variable global and require it to be returned. I realize that returning may be the only option.
function ($class_name) {
// Check if Exists
// __autoload will automatically include the file
// If it does not create a variable where the say '$people = new people();'
$class_name = new $class_name();
// Then if possible make this variable a globally accessible var.
}
Is this possible or am I being crazy?
eval is pretty much the only way to do this. It is very important you make sure this isn't provided by user input, like from $_GET or $_POST values.
function create_or_return($class_name) {
if(! class_exists($class_name)) {
eval("class $class_name { }");
// put it in the global scope
$GLOBALS[$class_name] = new $class_name;
}
}
create_or_return("Hello");
var_dump($GLOBALS['Hello']);
/*
class Hello#1 (0) {
}
*/
You can't really make it globally accessible because PHP doesn't have a global object like javascript does. But you can't simply make a container holding the object.
PHP has a function called class_exists($class_name), returns a bool.
http://www.php.net/manual/en/function.class-exists.php
Something along the lines of:
function some_fumction($class_name) {
if(class_exists($class_name)) {
return new $class_name;
} else {
throw new Exception("The class $class_name does not exist");
}
}
Related
I am testing a class, let's call it ClassUnderTest using another class, let's call it OtherClass. In my Test I do:
$OtherClassStub = $this->createStub(OtherClass::class);
$OtherClassStub->method(...)
->willReturn(...);
$ClassUnderTest->otherClass = $OtherClassStub;
That works. But when the $ClassUnderTest calls new OtherClass(), the original OtherClass class is created instead of the stub.
How can I achieve that every possible instance of OtherClass in the context of the test is replaced by the stub?
From your description I infer that in principle you have something like this:
class OtherClass {
protected function someMethod(): bool
{
// determine $x ...
return $x;
}
}
class ClassUnderTest {
public OtherClass $otherClass;
public function methodToBeTested(): bool
{
$otherClass = new OtherClass();
return $otherClass->someMethod();
}
}
class ClassUnderTestTest extends TestCase {
public function testMethodToBeTested(): void
{
$otherClassStub = $this->createStub(OtherClass::class);
$otherClassStub->method('someMethod')
->willReturn(true);
$classUnderTest = new ClassUnderTest();
$classUnderTest->otherClass = $otherClassStub;
$result = $classUnderTest->methodToBeTested();
$this->assertTrue($result);
}
}
Now the assertion in your test may hold or it may fail. Why? Because you are not calling the method you stubbed on the $otherClassStub. Instead you instantiate a new $otherClass object in the method you're testing (or somewhere down the line).
Either your ClassUnderTest should always use the OtherClass object from the ClassUndertTest::otherClass attribute (assuming that's why you put it there in the first place).
Or you could use some other form of dependency injection, e.g. by using a framework like Symfony or Laravel. (In the case of Symfony you can even use only the DependencyInjection Component, no idea if that's possible with Laravel, too.)
The simple answer to your actual question is: you cannot change the behaviour of the new keyword. Calling new on a class will always instantiate a new object based on exactly that class, unless the constructor of that class defines something else.
(You might want to get the concept of classes and objects straight, your code example as well as your question seem to indicate that you're not quite clear on that. Maybe reading up on that as well as on the concept of dependency injection will help you.)
Perhaps a solution to your problem is presented here:
How to Build a PHP Plugin Module System
This is one way to load classes as plugins and they can be called from each other. With modifying this system a bit, you can create as many "new OtherClass()" as you like from your code and still access everything from other classes. If you want multiple instances of a class, perhaps modify it into this direction:
function load ($module,$instance) {
if (isset($this->$module->$instance)) { return true; }
From above link:
<?php
class Core {
// (A) PROPERTIES
public $error = ""; // LAST ERROR MESSAGE
public $pdo = null; // DATABASE CONNECTION
public $stmt = null; // SQL STATEMENT
public $lastID = null; // LAST INSERT/UPDATE ID
// (B) LOAD SPECIFIED MODULE
// $module : module to load
function load ($module) {
// (B1) CHECK IF MODULE IS ALREADY LOADED
if (isset($this->$module)) { return true; }
// (B2) EXTEND MODULE ON CORE OBJECT
$file = PATH_LIB . "LIB-$module.php";
if (file_exists($file)) {
require $file;
$this->$module = new $module();
// EVIL POINTER - ALLOW OBJECTS TO ACCESS EACH OTHER
$this->$module->core =& $this;
$this->$module->error =& $this->error;
$this->$module->pdo =& $this->pdo;
$this->$module->stmt =& $this->stmt;
return true;
} else {
$this->error = "$file not found!";
return false;
}
}
}
ps. thank you for the mod, who made me work a bit more to keep this answer online. the answer is so much better now.
I have a called class called ClientPolicy which is like this
class ClientPolicy {
var $serverHost="www.example.com";
var $httpPort = 80;
var $httpsPort = 443;
var $appKey;
var $secKey;
var $defaultContentCharset = "UTF-8";
}
and another class file name SyncAPIClient which looks like this
class SyncAPIClient{
function SyncAPIClient(ClientPolicy $clientPolicy) {
$this->clientPolicy = $clientPolicy;
}
function SyncAPIClient($appKey, $appSecret) {
$this->clientPolicy = new ClientPolicy();
$this->clientPolicy->appKey=$appKey;
$this->clientPolicy->secKey=$appSecret;
}
}
My questions are
1.) If you check the function in SyncAPIClient, you will notice that the ClientPolicy class was passed as a parameter before a variable, what does it really mean? What is the essence of passing a class in function parameter?
2.) I am getting an error "Cannot redeclare SyncAPIClient::SyncAPIClient()" in my script log and the reason is that SyncAPIClient function was called twice in SyncAPIClient class. How can I solve this issue? Is there any better way to write this SyncAPIClient function instead of passing it twice?
The author of this script is nowhere to be found and I am left to fix it.
1) Here the $clientPolicy variable that is passed to this function, needs be a ClientPolicy instance.
In this way, if the argument that is passed is different from an instance of ClientPolice class, an error is generated.
function SyncAPIClient(ClientPolicy $clientPolicy) {
$this->clientPolicy = $clientPolicy;
}
https://wiki.php.net/rfc/typed_properties_v2
https://laravel-news.com/php7-typed-properties
2) The error Cannot redeclare SyncAPIClient::SyncAPIClient() is caused because you are trying to declare two functions called SyncAPIClient ().
If in first SyncAPIClient() method you just want save the $clientPolicy in $this->clientPolicy, you can use the magic method __construct. Or just try changing the name of one of the functions, and the problem should be a problem.
class SyncAPIClient{
__construct(ClientPolicy $clientPolicy) {
$this->clientPolicy = $clientPolicy;
}
function SyncAPIClient($appKey, $appSecret) {
$this->clientPolicy = new ClientPolicy();
$this->clientPolicy->appKey=$appKey;
$this->clientPolicy->secKey=$appSecret;
}
}
https://www.php.net/manual/en/language.oop5.decon.php
http://www.zentut.com/php-tutorial/php-constructor-and-destructor/
Hope this helps!
I would've fix the code you have like this:
class SyncAPIClient
{
private $clientPolicy = null;
function SyncAPIClient(ClientPolicy $clientPolicy = null)
{
if($clientPolicy instanceof ClientPolicy){
$this->clientPolicy = $clientPolicy;
}else{
$this->clientPolicy = new ClientPolicy();
}
}
public function setAuthParams($appKey, $appSecret) {
$this->clientPolicy->appKey=$appKey;
$this->clientPolicy->secKey=$appSecret;
}
}
This way you can instantiate a SyncAPIClient with or without a ClientPolicy.
Without ClientPolicy:
$syncAPI = new SyncAPIClient();
$syncAPI->setAuthParams($apiKey, $apiSecret);
With ClientPolicy:
$clientPolicy = new ClientPolicy();
$clientPolicy->appKey=$appKey;
$clientPolicy->secKey=$appSecret;
$syncAPI = new SyncAPIClient($clientPolicy);
When using class and functions in combination like
Rtin::
Functions nested inside that class Rtin should have different names than that class name
So you shouldn't have function called rtin
However you can call function from outside the class with it's name
From the error you have may be due to:
function you nested in the class or the function outside the class has a duplicate outside the script itself. Like having function mentioned in included function.php file and also mentioned in the script itself so php get confused because function name is written in two php files at the same time
Example of class
class Rtin{
private $data;
private $results;
public function getResultsType(){
return ........
}
}
To call class use
$q = Rtin::getResultsType($data['name']);
In your example. Adapt it to the example I have provide and review the included files for duplicate function .
I need an idea to create anonymous class on PHP. I don't know how I can works.
See my limitations:
On PHP you can't make anonymous class, like anonymous function (like class {});
On PHP you don't have class scope (except in namespaces, but it have the same problem below);
On PHP you can't use variables to specify the class name (like class $name {});
I don't have access to install the runkit PECL.
What I need, and why:
Well, I need create a function called ie create_class() that receives a key name and a anonymous class. It'll be useful for me because I want use different name class symbols that PHP can't accept. For instance:
<?php
create_class('it.is.an.example', function() {
return class { ... }
});
$obj = create_object('it.is.an.example');
?>
So, I need an idea that accept this use. I need it because on my framework I have this path: /modules/site/_login/models/path/to/model.php. So, the model.php need to declare a new class called site.login/path.to.model.
On call create_object() if the internal cache have a $class definition (like it.is.an.example it simply return the new class object. If not, need load. So I will use the $class content to search fastly what is the class file.
In PHP 7.0 there will be anonymous classes. I don't fully understand your question, but your create_class() function might look like this:
function create_class(string $key, array &$repository) {
$obj = new class($key) {
private $key;
function __construct($key) {
$this->key = $key;
}
};
$repository[$key] = $obj;
return $obj;
}
This will instantiate an object with an anonymous class type and register it into the $repository. To get an object out you use the key you created it with: $repository['it.is.an.example'].
You can create a dummy class using stdClass
$the_obj = new stdClass();
So basically you want to implement a factory pattern.
Class Factory() {
static $cache = array();
public static getClass($class, Array $params = null) {
// Need to include the inc or php file in order to create the class
if (array_key_exists($class, self::$cache) {
throw new Exception("Class already exists");
}
self::$cache[$class] = $class;
return new $class($params);
}
}
public youClass1() {
public __construct(Array $params = null) {
...
}
}
Add a cache within to check for duplicates
If you really need to to that, you could use eval()
$code = "class {$className} { ... }";
eval($code);
$obj = new $className ();
But the gods won't approve this. You will go to hell if you do it.
i have 2 classes
for DB
for language
i want to use my language things in the DB
so it outputs the result
ex :
class db_control{
var $db_connection, $lang_var;
//create the function for the connection
function db_connect(){
//define some variables
global $db_host, $db_username, $db_password, $db_name, $lang_var;
$this->db_connection = mysql_connect("$db_host","$db_username","$db_password")or die("can't connect to server with these informations");
//checl that the connection is established
if($this->db_connection){
echo $lang_vars->getvar("$langvals[lang_con_est]");
}
but this
$lang_vars->getvar("$langvals[lang_con_est]");
doesn't work
i mean it outputs many problems
and am sure my problem is that i didn't define my variables and classes correctly
P.S : the language class is in file called language.php and this part is in DB.MySQL.php
EDIT :
this is the language class
class lang_vars{
public static function getvar($variable){
return $variable;
}
}
i want the DB class to display text from the language class
thats why i used
echo $lang_vars->getvar("$langvals[lang_con_est]");
but it doesn't work
cuz when i declare the language class
$lang_vars = new lang_vars;
inside the db_control it shows error unexpected T_something expected T_Function
and when i declare it outside nothing up
hope i made things more clear now
Any reason why you are still using PHP4 syntax?
When creating an instance of the db_control class, pass the object to be stored as $lan_var into the constructor or set it via a dedicated setter. See Dependency Injection.
class DBControl
{
protected $_lang;
public function __construct($lang = NULL)
{
if($lang !== NULL) {
$this->_lang = $_lang;
}
}
public function setLang($lang)
{
$this->_lang = $lang;
}
}
Then do either
$dbControl = new DBControl(new LangThing);
or
$dbControl = new DBControl;
$dbControl->setLang(new LangThing);
Also, get rid of the globals. Pass those in via Dependency Injection too.
Make your language class methods static . Read more here.
class LangClass
{
public static function getvar()
{
// your code here
}
}
Then, you can use its functions without creating objects like this:
$LangClass::getvar("$langvals[lang_con_est]");
This can do the trick.
$lang_vars = new LanguageClassOrWhateverItIsCalled();
$lang_vars->getvar($langvals[lang_con_est]);
But maybe you should think of making it a static method. In that case you can call it with:
LanguageClassOrWhateverItIsCalled::getVar($langvals[lang_con_est]);
You can define the method static like:
public static function getVar() {
// Do something
}
Edit: #SAFAD
You should use the static method for this. To make this work, be sure your class language.php is loaded. To do so just add in the DB.MYSQL.php file the following line:
require_once('language.php');
class db_control {
...
Make sure you have the right path to the language.php file.
Then you should call the method in db_control class like this:
if($this->db_connection){
echo lang_vars::getvar("$langvals[lang_con_est]");
}
Besides, what is the use of a function like this? You should either do:
if($this->db_connection){
echo $langvals[lang_con_est];
}
or change your static getvar method to:
public static function getvar($variable){
return $langvals[$variable];
}
and your function call to:
if($this->db_connection){
echo lang_vars::getvar("lang_con_est");
}
Is a global PHP CONSTANT available inside of a Class file?
define('SITE_PATH', 'C:/webserver/htdocs/somefolder/');
Then in my class file I try this
public $debug_file = SITE_PATH. 'debug/debug.sql';
This does not seem to work though,
Parse error: parse error, expecting
','' or';'' in
C:\webserver\htdocs\somefolder\includes\classes\Database.class.php
on line 21
I second what the others said. Since $debugFile seems an optional dependency, I'd suggest to initialize a sane default on creation of the class and then allow changing it by setter injection when needed, e.g.
define('SITE_PATH', 'C:/webserver/htdocs/somefolder/');
class Klass
{
protected $_debugFile;
public function __construct()
{
$this->_debugFile = SITE_PATH. 'debug/debug.sql' // default
}
public function setDebugFile($path)
{
$this->_debugFile = $path // custom
}
}
Note that injecting SITE_PATH, instead of hardcoding it, would be even better practice.
You cannot have an expression in a class declaration.
I would suggest passing the path in:
public function __construct($path)
{
$this->debug_path = $path;
}
This gives you more flexibility if you ever want to change the path, you don't have to change a constant, just what you pass in.
Or you could create multiple objects that all have different paths. This is useful if it is an autoloader class, as you might want to have it load multiple directories.
$autoloader = new Autoload(dirname(SYS_PATH));
$autoloader->register_loader();
class Autoload
{
public $include_path = "";
public function __construct($include_path="")
{
// Set the Include Path
// TODO: Sanitize Include Path (Remove Trailing Slash)
if(!empty($include_path))
{
$this->include_path = $include_path;
}
else
{
$this->include_path = get_include_path();
}
// Check the directory exists.
if(!file_exists($this->include_path))
{
throw new Exception("Bad Include Path Given");
}
}
// .... more stuff ....
}
You can't use expression (.) in field initializer. See example one in PHP manual
Yes, however, property values defined at compile time cannot be expressions.
See http://php.net/manual/en/language.oop5.static.php