So, I'm converting some old code into a namespace, and trying to get autoload working. I've managed to follow the many good answers on this site about how to account for the namespace part of an autoloaded class (How do I use PHP namespaces with autoload?) - no problem.
Here's a different wrinkle, though. How do I autoload classes within the same namespace?
My autoload function (defined in a global include) is something like this:
function app_autoload($class)
{
$path = __DIR__.'/'.str_replace("\\", DIRECTORY_SEPARATOR, $class).'.php';
if (file_exists($path))
{
require_once($path);
}
}
spl_autoload_register('app_autoload');
If I have a class defined in the namespace app\nstest, I can autoload it just fine from most of my system:
namespace app\nstest;
class Test1
{
function hello()
{
echo "Hello world";
}
}
However, another class in the same namespace has issues:
namespace app\nstest;
class Test2
{
function callMe()
{
$test1 = new Test1();
}
}
If I explicitly include/require the Test1 file at the top of Test2, no problems, but the autoloader doesn't seem to be aware of the namespace, so it's loading "Test1.php" instead of "app/nstest/Test1.php".
I also tried checking the __NAMESPACE__ inside the autoloader, but it's empty.
Related
I did brows through that question page but the answers given, I felt, didn't sufficiently answer the question I was struggling with.
I have a little php project. In this project I define two classes both in their own files. The second class extends the first class. In the app.php file I instantiate the second class and call a method.
├── Models/
│ ├── Class1.php
│ └── Class2.php
└── app.php
<?php
// Class1.php
namespace Models\Class1;
/**
* Class1 does things
*/
class Class1 {
public function someMethod() {
// code
}
}
<?php
// Class2.php
namespace Models\Class2;
use \Models\Class1\Class1;
include('./Class1.php');
/**
* Class2 does other things
*/
class Class2 extends Class1 {
public function someMethod() {
// code
}
}
<?php
// app.php
use Models\Class1\Class1;
use Models\Class2\Class2;
require('Models/Class1.php');
require('Models/Class2.php');
$c1 = new Class1();
$c2 = new Class2();
Now I'm not a really experienced php programmer but I thought I had a solid grasp of this class/namespace business and including/requiring files, but apparently I don't.
If I copy the methods I need from Class1 to Class2 and not extend/include/use Class2 everything works fine, but want to extend Class1, so I don't have to repeat myself! Damn it!
This is what I get when running the app.php file.
Warning: include(../Models/Class1.php): failed to open stream: No such file or directory in C:\wamp64\www\project\Models\Class2.php on line 8
Warning: include(): Failed opening '../Models/Class1.php' for inclusion (include_path='.;C:\php\pear') in C:\wamp64\www\project\Models\Class2.php on line 7
I've been reading all I can find online about this stuff, have written and rewritten my code in a dozen different ways but have yet to find a solution. Some help would be greatly appreciated!
Quick Answer
Unless you've specified the full path to the include file, PHP will always try to resolve files according to the location of the entry script. In your case, your entry script seems to be app.php at the root of the application.
So in your Class2.php, instead of include('./Class1.php');, you should write include('Models/Class1.php'); and things should work. But while it fix a short term problem, your code would be really non-portable. Besides, including the same file twice would result in another error (e.g. re-declaring class).
Slightly Smarter Approach
A slightly smarter would be to do this in Class2.php instead.
<?php
// Class2.php
namespace Models\Class2;
use \Models\Class1\Class1;
include_once __DIR__ . '/Class2.php';
/**
* Class2 does other things
*/
class Class2 extends Class1 {
public function someMethod() {
// code
}
}
The variable __DIR__ will always be resolved to the directory of the script file, not the entry script.
But again, it is clumsy and error prone to do file includes by hand.
An Even Smarter Approach: Autoload
PHP supports file autoloading when a class is declare. That is to have a piece of code to do the file include when a class is called. If you want to have fun, you're welcome to write your own autoloader function and register to spl_autoload_register. With a combination of the __DIR__ technique we talked about, you can easily resolve the autoloading path from namespace.
A quick and ugly autoloading app.php would probably look like this:
<?php
// app.php
use Models\Class1\Class1;
use Models\Class2\Class2;
spl_autoload_register(function ($class_name) {
$realClassName = basename(str_replace('\\', DIRECTORY_SEPARATOR, $class_name));
include_once __DIR__ . DIRECTORY_SEPARATOR . 'Models' . DIRECTORY_SEPARATOR . $realClassName . '.php';
});
$c1 = new Class1();
$c2 = new Class2();
The Smart Approach: Composer Autoload
If you're learning OOP PHP today, I'd highly recommend you to learn Composer and PSR-4. PSR-4 defines how you should structure a PHP application for class autoloading. Composer implements a PSR-4 autoloader by default.
First you should comply with the namespace standard. The least change to do is to loose the extra "Class1" and "Class2" in your namespace:
<?php
// Class1.php
namespace Models;
/**
* Class1 does things
*/
class Class1 {
public function someMethod() {
// code
}
}
<?php
// Class2.php
namespace Models;
use \Models\Class1;
/**
* Class2 does other things
*/
class Class2 extends Class1 {
public function someMethod() {
// code
}
}
With a nicely structured application folder, namespace structure and a correctly written autoload.psr-4 section in composer.json, composer will help you to generate a class autoloader. Your composer.json would probably look like this:
{
"autoload": {
"psr-4": {
"Model\\": "Model/"
}
}
}
You may now run composer dump-autoload to create the autoloader. Then you can simply add this to your entry script app.php. When things are ready, you may simply add use and new statement anywhere in the application.:
<?php
// app.php
use Models\Class1;
use Models\Class2;
require_once './vendor/autoload.php';
$c1 = new Class1();
$c2 = new Class2();
All includes are handled by the autoloader. Hands free.
Remove the line
include('./Class1.php');
I created a class at Controller folder of Cake project like this:
<?php
class Hi
{
function __construct(){ }
public function hi()
{
echo "hi!";
exit;
}
}
Then in a controller, I tried to include it:
<?php
namespace App\Controller;
use App\Controller\AppController;
include_once "Hi.php";
class MyController extends AppController
{
public function sayHi()
{
$a = new Hi();
$a.hi();
}
}
Here is the error I'm having:
Fatal error: Cannot declare class Hi, because the name is already in use in path\api\src\Controller\Hi.php on line 2
What's going on?
MyController.php and Hi.php are in the same folder. I'm using PHP 7.
Including a file won't make the classes in that file part of the current namespace, as namespaces are a per-file functionality.
http://php.net/...namespaces.importing.php#language.namespaces.importing.scope
Your Hi class will be declared in the global namespace, and your new Hi() will cause PHP to look for it in the current namespace, ie it will look for App\Controller\Hi, which doesn't exist, hence the composer autoloader kicks in, and will map this via a PSR-4 namespace prefix match to src/Controller/Hi.php, which will include the file again, and that's when it happens.
http://www.php-fig.org/psr/psr-4/
Long story short, while using new \Hi() would fix this, you better not include class files manually, or declare them in paths where they do not belong. Instead declare your files and classes in a proper autoloading compatible fashion, that is for example with a proper namespace in a path that matches that namespace, like
namespace App\Utils;
class Hi {
// ...
}
in
src/Utils/Hi.php
on index.php I have below code
require 'Bootstrap.php';
require 'Variables.php';
function __autoload($class){
$class = str_replace('Control\\', '', $class);
require_once 'class/'.$class.'.php';
}
$bootstratp = new Control\Bootstrap();
on Bootstrap.php
namespace Control;
class Bootstrap{
function __construct(){
Constructor::load_html();
self::same_namespace_different_class();
}
static function same_namespace_different_class(){
Variables::get_values();
}
}
in class/Constructor.php
class Constructor{
static function load_html(){
echo 'html_loaded';
}
static function load_variables(){
echo 'load variables';
}
}
and on Variables.php
namespace Control;
class Variables{
static function get_values(){
Constructor::load_variables();
}
}
Assume, In total I have 4 PHP files including 3 Class files of 2 different namespaces. I also have a __autoload function on index.php that will call classes from 'class' folder but my 'Control' namespace files are in root folder.
When I echo the class name in __autoload i get the all the class names starting with 'Control\' even when I am calling a class from global namespace.
I am getting below error
Warning: require_once(class/Variables.php): failed to open stream: No such file or directory in _____________ on line 10
what is wrong with my code??
When I echo the class name in __autoload i get the all the class names starting with 'Control\' even when I am calling a class from global namespace.
This is because in Bootstrap.php all the code is in Control namespace (namespace Control). So when you use:
Variables::get_values();
you call
\Control\Variables::get_values();
if you want to use Variables from global namespace you should use here:
\Variables::get_values();
Of course, the same happens for in Variables.php file:
Constructor::load_variables();
As Constructor is defined in global namespace (in class/Constructor.php there is no namespace used), you should access it here using:
\Constructor::load_variables();
If it's still unclear you could also look at this question about namespaces in PHP.
You should also notice that using __autoload is not recommended. You should use spl_autoload_register() now. Documentation about autoloading
I use symfony 2.4.0. I want to use my custom class as discussed here: Autoloading a class in Symfony 2.1. I have created subfolder in src:
namespace Yur;
class MyClass {
public go() {
var_dump('hello!! 32');
}
}
In my controller, I made this:
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Yur\MyClass;
class WelcomeController extends Controller
{
public function indexAction()
{
$my = new MyClass();
$my->go();
die();
...
but it makes an exception:
ClassNotFoundException: Attempted to load class "MyClass" from namespace "Yur" in /var/www/shop.loc/src/Acme/DemoBundle/Controller/WelcomeController.php line 12. Do you need to "use" it from another namespace?
After I have got this exception, I decided consciously to make syntax error exception in my class to see if it loaded. I changed class MyClass ... to class4 MyClass ..., but doesnt got asyntax error` exception. And I decided, that my class is not loaded.
Is anyone knows why? And what I must to do to resolve?
A few things. First, in your code sample above, you have
public go() {
var_dump('hello!! 32');
}
which should be
public function go() {
var_dump('hello!! 32');
}
The former raises a parser error in PHP. and probably isn't what you want.
Second, the error
ClassNotFoundException: Attempted to load class "MyClass" from namespace "Yur" in /var/www/shop.loc/src/Acme/DemoBundle/Controller/WelcomeController.php line 12. Do you need to "use" it from another namespace?
is the error Symfony uses when it attempt to autoload a class, but can't find the file. This usually means your file is named incorrectly, or in the wrong folder. I'd tripped check that you have a file in the directory you think you do.
$ ls src/Yur/MyClass.php
You can also add some debugging to the composer autoload code to see what path it's cooking up for your custom class
#File: vendor/composer/ClassLoader.php
public function findFile($class)
{
//...
$classPath .= strtr($className, '_', DIRECTORY_SEPARATOR) . '.php';
//start your debugging code
if($class == 'Yur\MyClass')
{
//dump the generated path
var_dump($classPath);
//dump the default include paths
var_dump($this->fallbackDirs);
}
//...
}
I have a question about namespaces in PHP.
this code doesn't work :
<?php
namespace My\Functions\Printing;
class A {
public function __construct() {
echo __NAMESPACE__;
}
}
namespace My;
use My\Functions\Printing\A as A;
$obj=new namespace\A();
But this one work :
<?php
namespace My\Functions\Printing;
class A {
public function __construct() {
echo __NAMESPACE__;
}
}
namespace My;
use My\Functions\Printing\A as A;
$obj=new A();
I would like to get more information about the behavior of namespaces importation.
Why an imported class can't be accessible in the namespace where it is imported?
Probably you have a confused idea of using 'use'.
The keyword 'namespace' refers to the current namespace
namespace My\Functions\Printing;
class A {
public function __construct() {
echo __NAMESPACE__;
}
}
namespace My;
use My\Functions\Printing\A;
use My\Functions\Printing\A as myAlias;
$obj=new namespace\A(); // instance of \My\A (doesn't exist)
$obj2=new A(); // instance of \My\Functions\Printing\A
$obj3=new myAlias(); // instance of \My\Functions\Printing\A
As usual, see the documentation for complete details: php doc
I'm not sure but I think problem is in using namespace keyword.
http://www.php.net/manual/pl/language.namespaces.nsconstants.php
In first example you are in My namespace so namespace\A() == My\My\Functions\Printing\A()
My\Functions\Printing namespace look like
-- My\Functions\Printing
A
"My" namespace before importation look like:
-- My
"My" namespace after importation should look like (i thinks)
-- My
A
So why i can't acces My\A ?
I think the structure of namespace it's not changed an PHP compiler check in the "namespace imported area" before the "namespace structure".
Documentation specify namespaces look like filesystem, it's false.
If an importation of an other class is as "create a symbolic link" i must be able to acced it from the current namespace.
We can acced a symbolic link from the directory where it was created or from the absolute path but it's not possible to acced the imported class
with its new path. (\My\A)
Why ?