I want to create a class of which I don't know the name. What is the best way to accomplish the following scenario in PHP?
$class_name = 'SomeClassName';
$code = "class {$class_name}_Control extends WP_Customize_Control {}";
eval( $code );
Thanks.
I just tested this and it works fine. And if you only need the class temporarily you can always throw an unlink() at the bottom. No exec() required.
<?php
// your dynamic classname
$fart = "poot";
// define your class, don't forget the "<?php"
$class = <<<YOYOYOHOMIE
<?php
class $fart{
public \$poop = "poop";
}
YOYOYOHOMIE;
// write the class to a file.
$filename = "dynamicClass".time().".php";
$fh = fopen($filename,"w+");
fwrite($fh, $class);
fclose($fh);
// require the file
require $filename;
// now your dynamically generated class is available
$tird = new $fart;
echo "<pre>";
var_dump($tird);
Related
I'm working on a project whereby I have the following file structure:
index.php
|---lib
|--|lib|type|class_name.php
|--|lib|size|example_class.php
I'd like to auto load the classes, class_name and example_class (named the same as the PHP classes), so that in index.php the classes would already be instantiated so I could do:
$class_name->getPrivateParam('name');
I've had a look on the net but can't quite find the right answer - can anyone help me out?
EDIT
Thanks for the replies. Let me expand on my scenario. I'm trying to write a WordPress plugin that can be dropped into a project and additional functionality added by dropping a class into a folder 'functionality' for example, inside the plugin. There will never be 1000 classes, at a push maybe 10?
I could write a method to iterate through the folder structure of the 'lib' folder, including every class then assigning it to a variable (of the class name), but didn't think that was a very efficient way to do it but it perhaps seems that's the best way to achieve what I need?
Please, if you need to autoload classes - use the namespaces and class names conventions with SPL autoload, it will save your time for refactoring.
And of course, you will need to instantiate every class as an object.
Thank you.
Like in this thread:
PHP Autoloading in Namespaces
But if you want a complex workaround, please take a look at Symfony's autoload class:
https://github.com/symfony/ClassLoader/blob/master/ClassLoader.php
Or like this (I did it in one of my projects):
<?
spl_autoload_register(function($className)
{
$namespace=str_replace("\\","/",__NAMESPACE__);
$className=str_replace("\\","/",$className);
$class=CORE_PATH."/classes/".(empty($namespace)?"":$namespace."/")."{$className}.class.php";
include_once($class);
});
?>
and then you can instantiate your class like this:
<?
$example=new NS1\NS2\ExampleClass($exampleConstructParam);
?>
and this is your class (found in /NS1/NS2/ExampleClass.class.php):
<?
namespace NS1\NS2
{
class Symbols extends \DB\Table
{
public function __construct($param)
{
echo "hello!";
}
}
}
?>
If you have an access to the command line, you can try it with composer in the classMap section with something like this:
{
"autoload": {
"classmap": ["yourpath/", "anotherpath/"]
}
}
then you have a wordpress plugin to enable composer in the wordpress cli : http://wordpress.org/plugins/composer/
function __autoload($class_name) {
$class_name = strtolower($class_name);
$path = "{$class_name}.php";
if (file_exists($path)) {
require_once($path);
} else {
die("The file {$class_name}.php could not be found!");
}
}
UPDATE:
__autoload() is deprecated as of PHP 7.2
http://php.net/manual/de/function.spl-autoload-register.php
spl_autoload_register(function ($class) {
#require_once('lib/type/' . $class . '.php');
#require_once('lib/size/' . $class . '.php');
});
I have an example here that I use for autoloading and initiliazing.
Basically a better version of spl_autoload_register since it only tries to require the class file whenever you initializes the class.
Here it automatically gets every file inside your class folder, requires the files and initializes it. All you have to do, is name the class the same as the file.
index.php
<?php
require_once __DIR__ . '/app/autoload.php';
$loader = new Loader(false);
User::dump(['hello' => 'test']);
autoload.php
<?php
class Loader
{
public static $library;
protected static $classPath = __DIR__ . "/classes/";
protected static $interfacePath = __DIR__ . "/classes/interfaces/";
public function __construct($requireInterface = true)
{
if(!isset(static::$library)) {
// Get all files inside the class folder
foreach(array_map('basename', glob(static::$classPath . "*.php", GLOB_BRACE)) as $classExt) {
// Make sure the class is not already declared
if(!in_array($classExt, get_declared_classes())) {
// Get rid of php extension easily without pathinfo
$classNoExt = substr($classExt, 0, -4);
$file = static::$path . $classExt;
if($requireInterface) {
// Get interface file
$interface = static::$interfacePath . $classExt;
// Check if interface file exists
if(!file_exists($interface)) {
// Throw exception
die("Unable to load interface file: " . $interface);
}
// Require interface
require_once $interface;
//Check if interface is set
if(!interface_exists("Interface" . $classNoExt)) {
// Throw exception
die("Unable to find interface: " . $interface);
}
}
// Require class
require_once $file;
// Check if class file exists
if(class_exists($classNoExt)) {
// Set class // class.container.php
static::$library[$classNoExt] = new $classNoExt();
} else {
// Throw error
die("Unable to load class: " . $classNoExt);
}
}
}
}
}
/*public function get($class)
{
return (in_array($class, get_declared_classes()) ? static::$library[$class] : die("Class <b>{$class}</b> doesn't exist."));
}*/
}
You can easily manage with a bit of coding, to require classes in different folders too. Hopefully this can be of some use to you.
You can specify a namespaces-friendly autoloading using this autoloader.
<?php
spl_autoload_register(function($className) {
$file = __DIR__ . '\\' . $className . '.php';
$file = str_replace('\\', DIRECTORY_SEPARATOR, $file);
if (file_exists($file)) {
include $file;
}
});
Make sure that you specify the class file's location corretly.
Source
spl_autoload_register(function ($class_name) {
$iterator = new DirectoryIterator(dirname(__FILE__));
$files = $iterator->getPath()."/classes/".$class_name.".class.php";
if (file_exists($files)) {
include($files);
} else {
die("Warning:The file {$files}.class.php could not be found!");
}
});
do this in a file and called it anything like (mr_load.php)
this were u put all your classes
spl_autoload_register(function($class){
$path = '\Applicaton/classes/';
$extension = '.php';
$fileName = $path.$class.$extension;
include $_SERVER['DOCUMENT_ROOT'].$fileName;
})
;
then create another file and include mr_load.php; $load_class = new BusStop(); $load_class->method()
How can I check if a class exists already in a folder then do not load this class again from another folder?
I have this folder structure for instance,
index.php
code/
local/
And I have these two identical classes in code/ and local/
from local/
class Article
{
public function getArticle()
{
echo 'class from local';
}
}
from core,
class Article
{
public function getArticle()
{
echo 'class from core';
}
}
So I need a script that can detects the class of Article in local/ - if it exits already in that folder than don't load the class again from core/ folder. Is it possible?
This is my autoload function in index.php for loading classes,
define ('WEBSITE_DOCROOT', str_replace('\\', '/', dirname(__FILE__)).'/');
function autoloadMultipleDirectory($class_name)
{
// List all the class directories in the array.
$main_directories = array(
'core/',
'local/'
);
// Set other vars and arrays.
$sub_directories = array();
// When you use namespace in a class, you get something like this when you auto load that class \foo\tidy.
// So use explode to split the string and then get the last item in the exloded array.
$parts = explode('\\', $class_name);
// Set the class file name.
$file_name = end($parts).'.php';
// List any sub dirs in the main dirs above and store them in an array.
foreach($main_directories as $path_directory)
{
$iterator = new RecursiveIteratorIterator
(
new RecursiveDirectoryIterator(WEBSITE_DOCROOT.$path_directory), // Must use absolute path to get the files when ajax is used.
RecursiveIteratorIterator::SELF_FIRST
);
foreach ($iterator as $fileObject)
{
if ($fileObject->isDir())
{
// Replace any backslash to '/'.
$pathnameReplace = str_replace('\\', '/', $fileObject->getPathname());
//print_r($pathnameReplace);
// Explode the folder path.
$array = explode("/",$pathnameReplace);
// Get the actual folder.
$folder = end($array);
//print_r($folder);
// Stop proccessing if the folder is a dot or double dots.
if($folder === '.' || $folder === '..') {continue;}
//var_dump($fileObject->getPathname());
// Must trim off the WEBSITE_DOCROOT.
$sub_directories[] = preg_replace('~.*?(?=core|local)~i', '', str_replace('\\', '/', $fileObject->getPathname())) .'/';
}
}
}
// Mearge the main dirs with any sub dirs in them.
$merged_directories = array_merge($main_directories,$sub_directories);
// Loop the merge array and include the classes in them.
foreach($merged_directories as $path_directory)
{
if(file_exists(WEBSITE_DOCROOT.$path_directory.$file_name))
{
// There is no need to use include/require_once. Autoload is a fallback when the system can't find the class you are instantiating.
// If you've already included it once via an autoload then the system knows about it and won't run your autoload method again anyway.
// So, just use the regular include/require - they are faster.
include WEBSITE_DOCROOT.$path_directory.$file_name;
}
}
}
// Register all the classes.
spl_autoload_register('autoloadMultipleDirectory');
$article = new Article();
echo $article->getArticle();
of course I get this error,
Fatal error: Cannot redeclare class Article in C:\wamp\...\local\Article.php on line 3
class_exists seems to be the answer I should look into, but how can I use it with the function above, especially with spl_autoload_register. Or if you have any better ideas?
Okay, I misunderstood your question. This should do the trick.
<?php
function __autoload($class_name) {
static $core = WEBSITE_DOCROOT . DIRECTORY_SEPARATOR . "core";
static $local = WEBSITE_DOCROOT . DIRECTORY_SEPARATOR . "local";
$file_name = strtr($class_name, "\\", DIRECTORY_SEPARATOR):
$file_local = "{$local}{$file_name}.php";
require is_file($file_local) ? $file_local : "{$core}{$file_name}.php";
}
This is easily solved by using namespaces.
Your core file goes to /Core/Article.php:
namespace Core;
class Article {}
Your local file goes to /Local/Article.php:
namespace Local;
class Article {}
And then use a very simple autoloader, e.g.:
function __autoload($class_name) {
$file_name = strtr($class_name, "\\", DIRECTORY_SEPARATOR);
require "/var/www{$file_name}.php";
}
PHP loads your classes on demand, there's no need to load the files up front!
If you want to use an article simply do:
<?php
$coreArticle = new \Core\Article();
$localArticle = new \Local\Article();
I'm working on a project whereby I have the following file structure:
index.php
|---lib
|--|lib|type|class_name.php
|--|lib|size|example_class.php
I'd like to auto load the classes, class_name and example_class (named the same as the PHP classes), so that in index.php the classes would already be instantiated so I could do:
$class_name->getPrivateParam('name');
I've had a look on the net but can't quite find the right answer - can anyone help me out?
EDIT
Thanks for the replies. Let me expand on my scenario. I'm trying to write a WordPress plugin that can be dropped into a project and additional functionality added by dropping a class into a folder 'functionality' for example, inside the plugin. There will never be 1000 classes, at a push maybe 10?
I could write a method to iterate through the folder structure of the 'lib' folder, including every class then assigning it to a variable (of the class name), but didn't think that was a very efficient way to do it but it perhaps seems that's the best way to achieve what I need?
Please, if you need to autoload classes - use the namespaces and class names conventions with SPL autoload, it will save your time for refactoring.
And of course, you will need to instantiate every class as an object.
Thank you.
Like in this thread:
PHP Autoloading in Namespaces
But if you want a complex workaround, please take a look at Symfony's autoload class:
https://github.com/symfony/ClassLoader/blob/master/ClassLoader.php
Or like this (I did it in one of my projects):
<?
spl_autoload_register(function($className)
{
$namespace=str_replace("\\","/",__NAMESPACE__);
$className=str_replace("\\","/",$className);
$class=CORE_PATH."/classes/".(empty($namespace)?"":$namespace."/")."{$className}.class.php";
include_once($class);
});
?>
and then you can instantiate your class like this:
<?
$example=new NS1\NS2\ExampleClass($exampleConstructParam);
?>
and this is your class (found in /NS1/NS2/ExampleClass.class.php):
<?
namespace NS1\NS2
{
class Symbols extends \DB\Table
{
public function __construct($param)
{
echo "hello!";
}
}
}
?>
If you have an access to the command line, you can try it with composer in the classMap section with something like this:
{
"autoload": {
"classmap": ["yourpath/", "anotherpath/"]
}
}
then you have a wordpress plugin to enable composer in the wordpress cli : http://wordpress.org/plugins/composer/
function __autoload($class_name) {
$class_name = strtolower($class_name);
$path = "{$class_name}.php";
if (file_exists($path)) {
require_once($path);
} else {
die("The file {$class_name}.php could not be found!");
}
}
UPDATE:
__autoload() is deprecated as of PHP 7.2
http://php.net/manual/de/function.spl-autoload-register.php
spl_autoload_register(function ($class) {
#require_once('lib/type/' . $class . '.php');
#require_once('lib/size/' . $class . '.php');
});
I have an example here that I use for autoloading and initiliazing.
Basically a better version of spl_autoload_register since it only tries to require the class file whenever you initializes the class.
Here it automatically gets every file inside your class folder, requires the files and initializes it. All you have to do, is name the class the same as the file.
index.php
<?php
require_once __DIR__ . '/app/autoload.php';
$loader = new Loader(false);
User::dump(['hello' => 'test']);
autoload.php
<?php
class Loader
{
public static $library;
protected static $classPath = __DIR__ . "/classes/";
protected static $interfacePath = __DIR__ . "/classes/interfaces/";
public function __construct($requireInterface = true)
{
if(!isset(static::$library)) {
// Get all files inside the class folder
foreach(array_map('basename', glob(static::$classPath . "*.php", GLOB_BRACE)) as $classExt) {
// Make sure the class is not already declared
if(!in_array($classExt, get_declared_classes())) {
// Get rid of php extension easily without pathinfo
$classNoExt = substr($classExt, 0, -4);
$file = static::$path . $classExt;
if($requireInterface) {
// Get interface file
$interface = static::$interfacePath . $classExt;
// Check if interface file exists
if(!file_exists($interface)) {
// Throw exception
die("Unable to load interface file: " . $interface);
}
// Require interface
require_once $interface;
//Check if interface is set
if(!interface_exists("Interface" . $classNoExt)) {
// Throw exception
die("Unable to find interface: " . $interface);
}
}
// Require class
require_once $file;
// Check if class file exists
if(class_exists($classNoExt)) {
// Set class // class.container.php
static::$library[$classNoExt] = new $classNoExt();
} else {
// Throw error
die("Unable to load class: " . $classNoExt);
}
}
}
}
}
/*public function get($class)
{
return (in_array($class, get_declared_classes()) ? static::$library[$class] : die("Class <b>{$class}</b> doesn't exist."));
}*/
}
You can easily manage with a bit of coding, to require classes in different folders too. Hopefully this can be of some use to you.
You can specify a namespaces-friendly autoloading using this autoloader.
<?php
spl_autoload_register(function($className) {
$file = __DIR__ . '\\' . $className . '.php';
$file = str_replace('\\', DIRECTORY_SEPARATOR, $file);
if (file_exists($file)) {
include $file;
}
});
Make sure that you specify the class file's location corretly.
Source
spl_autoload_register(function ($class_name) {
$iterator = new DirectoryIterator(dirname(__FILE__));
$files = $iterator->getPath()."/classes/".$class_name.".class.php";
if (file_exists($files)) {
include($files);
} else {
die("Warning:The file {$files}.class.php could not be found!");
}
});
do this in a file and called it anything like (mr_load.php)
this were u put all your classes
spl_autoload_register(function($class){
$path = '\Applicaton/classes/';
$extension = '.php';
$fileName = $path.$class.$extension;
include $_SERVER['DOCUMENT_ROOT'].$fileName;
})
;
then create another file and include mr_load.php; $load_class = new BusStop(); $load_class->method()
I'm new to OOP terminology, I am trying to create a class that make a hit counter.
I try the code below but it create just a counter.txt page with inside value 1. I dont know why its not incrementing.
class LOGFILE {
public function READ($FileName) {
$handle = fopen($FileName, 'r');
$fread = file_get_contents($FileName);
return $fread;
fclose($handle);
}
public function WRITE($FileName, $FileData) {
$handle = fopen($FileName, 'w');
$FileData = $fread +1;
fwrite($handle, $FileData);
fclose($handle);
}
}
$logfile = new LOGFILE();
$logfile -> WRITE("counter.txt",$FileData);
echo $logfile -> READ("counter.txt");
The reason is that $fread is local variable for both READ and WRITE methods. You need to make it private global variable for your class:
class LOGFILE {
private $fread;
public function READ($FileName) {
$this->fread = file_get_contents($FileName);
return $this->fread;
}
public function WRITE($FileName) {
$this->READ($FileName);
$handle = fopen($FileName, 'w');
$FileData = $this->fread +1;
fwrite($handle, $FileData);
fclose($handle);
}
}
$logfile = new LOGFILE();
$logfile -> WRITE("counter.txt");
echo $logfile -> READ("counter.txt");
Note: I have removed fopen and fclose because file_get_contents does not need it. In write you can use file_put_contents. Removed not used variable $FileData too. It's always a good practice to create variables methods and classes when they are needed.
Also take a look at best practices how to name your classes, variables, methods and so on. Here's best guide, IMO.
Let's start going over the corrected code and see what was missing:
<?php
class LOGFILE {
public function READ($FileName) {
$handle = fopen($FileName, 'r');
$fread = fgets($handle, 8192);
fclose($handle);
return $fread;
}
public function WRITE($FileName, $FileData) {
$counter = $this->READ($FileName);
$handle = fopen($FileName, 'w');
fwrite($handle, $FileData + $counter);
fclose($handle);
}
}
$logfile = new LOGFILE();
$FileData = 1;
$logfile -> WRITE("counter.txt",$FileData);
echo $logfile -> READ("counter.txt")."\n";
$logfile -> WRITE("counter.txt",$FileData);
echo $logfile -> READ("counter.txt")."\n";
?>
use of fgets instead of file_get_contents in READ (you can choose to use file_get_contents but I rather stay consistent with the other function that uses fopen)
use of READ inside function WRITE (the principal of code-reuse)
open of file with write permissions in WRITE: 'w'
init $FileData = 1;
no need to hold a private member: $fread
most important: do not write statements after return (like you did in READ) - statements that are written after return will not be executed!
This solution was tested successfully.
OOP must be used where it's needed. You need a simple thing so, no need of OOP.
<?php
function addValue($file='counter.txt', $amount=1) {
if( false == is_file($file) ) {
return false;
}
$initial = file_get_contents($file);
return #file_put_contents($initial+$amount);
}
addValue();
?>
Test your OOP knowledge on something complex, like a shopping cart or some other concept.
EDIT // so, if you need a simple example that looks complex, here you go :)
<?php
class log {
public $file = '';
private $amount = 0;
public function __construct( $file ) {
$this->file = $file;
$this->amount = 1;
}
public function makeAdd() {
$initial = file_get_contents($this->file);
return #file_put_contents($this->file, $initial + $this->amount);
}
function __call($f, $args) {
switch( $f ) {
case 'add':
if(isset($args[0]) && !empty($args[0])) {
$this->amount = (int)$args[0];
}
if( $this->amount == 0 ) {
throw new Exception('Not a valid amount.');
}
return $this->makeAdd();
break;
}
}
}
try {
// create log
$L = new log('count.txt');
// this will add 2
var_dump($L->add(2));
// this will also add 2
var_dump($L->add());
// until you rewrite the amount
var_dump($L->add(1));
// final result -> 5
} catch(Exception $e) {
die($e->getMessage());
}
?>
Good luck!
Use UpperCamelCase for class names. LogFile, not LOGFILE. When you have a variable and the most interesting thing about it is that it's expected to hold a reference to something that is_a LogFile you should name it logFile.
Use lowerCamelCase for functions. read and write, not READ and WRITE
No spaces around the arrow operator
Code after a return statement in a method can never be reached, so delete it.
read() does not use the handle returned by fopen, so don't call fopen
the temp variable $freed doesn't help us understand the code, so we can lose it
read is a slightly unconventional name. If we rename the function to getCount it will be more obvious what it does.
You said you wanted to make a hit counter. So rename the class from LogFile to HitCounter, and the variable to hitCounter
the $FileData parameter to write doesn't get used because the variable is re-assigned inside the function. We can lose it.
The write method is supposed to add one to the number in the file. Write doesn't really express that. Rename it to increment.
Use a blank line between functions. The procedural code at the end should generally be in a separate file, but here we can just add a couple of extra lines. Delete the blanks between the last three lines of code.
Don't repeat yourself - we shouldn't have to mention 'counter.txt' more than once. OOP is all about combining data structures and behaviour into classes, so make a class private variable to hold the filename, and pass it via a constructor
$fread doesn't exist in the scope of increment, so we can't use it. This won't work. Replace it with a call to to getCount()
Swap the first two lines of increment, so we're not doing two concurent accesses to the same file, although we might be running inside a server that's running our script twice and still doing two concurrent accesses.
Rename the variable $FileData to $count, since that's what it is.
Replace the fopen,fwrite,fclose sequence with file_put_contents, since that does the same thing and is more succinct.
We need tag, since our php code continues to the end of the file.
That leaves us with:
<?php
class HitCounter {
private $fileName;
public function __construct($fileName){
$this->fileName = $fileName;
}
public function getCount() {
return file_get_contents($this->fileName);
}
public function increment() {
$count = $this->getCount() + 1;
file_put_contents($this->fileName, $count);
}
}
$hitCounter = new HitCounter("counter.txt");
$hitCounter->increment();
echo $hitCounter->getCount();
You can create a static counter and increment it each time (instead of create file)
<?php
class CountClass {
public static $counter = 0;
function __construct() {
self::$counter++;
}
}
new CountClass();
new CountClass();
echo CountClass::$counter;
?>
I have directory CLASSES with files in my project.
../classes/class.system.php
../classes/class.database.php
...
I pull out every class and include it to main index.php with this code:
// load classes
foreach (glob("classes/class.*.php") as $filename) {
require_once $filename;
}
and then I create (manually write) objects for example:
$system = new System();
$database = new Database();
...
Q: How can I automatically generate object for each class from list of files in directory CLASSES without writing them?
Thank you for your answers and code.
EDIT:
My working solution:
// load classes
foreach (glob("classes/class.*.php") as $filename) {
require_once $filename;
$t = explode(".",$filename);
$obj = strtolower($t[1]);
$class = ucfirst($t[1]);
${$obj} = new $class();
}
IF you follow a typical pattern, while creating those files like
class.<classname>.php
Then
foreach (glob("classes/class.*.php") as $filename) {
require_once $filename;
$t = explode(".",$filename);
${strtolower($t[1])}= new ucfirst($t[1])(); // automatically create the object
}
I don't think loading all classes with glob and including them if you need or not is efficient or good idea performance wise. What if you have 500 different classes ???
Why don't you take advantage of PHP auto loading see http://php.net/manual/en/language.oop5.autoload.php which would only load the class you need
Example
function __autoload($className) {
require_once "classes/class." . $className . ".php";
}
$system = new System();
$database = new Database();
// load classes and create objects
foreach (glob("classes/class.*.php") as $filename) {
require_once $filename;
$t = explode(".",$filename);
$obj = strtolower($t[1]);
$class = ucfirst($t[1]);
// create object for every class
${$obj} = new $class();
}