PHP Autoloading in Namespaces - php

Question

I have had a slight problem with autoloading in my namespace. As shown on the PHP manual here: http://us.php.net/manual/en/language.namespaces.rules.php you should be able to autoload namespace functions with a full qualified name e.g. \glue\common\is_email().
Thing is I have a function spl_autoload_register(array($import, "load")); within the initial namespace but whenever I try and call \glue\common\is_email() from the initial namespace it will not pass that autoload function but when using new is_email() (in the context of a class) it will. I don't get it the manual says I can autoload from fully qualified names but I can't :.
Here's my code:
namespace glue;
require_once 'import.php';
use glue\import as import;
use glue\core\router as router;
$import = new import();
spl_autoload_register(array($import, "load"));
/** Works and echos glue\router **/
$router = new router();
/** Don't do nothing **/
$cheese = \glue\common\is_email($email);
I also tried this code as well:
namespace glue;
require_once 'import.php';
use glue\import as import;
use glue\core\router as router;
use glue\common;
$import = new import();
spl_autoload_register(array($import, "load"));
/** Works and echos glue\router **/
$router = new router();
/** Don't do nothing **/
$cheese = common\is_email($email);
and finally this code:
namespace glue;
require_once 'import.php';
use glue\import as import;
use glue\core\router as router;
use glue\common\is_email as F;
$import = new import();
spl_autoload_register(array($import, "load"));
/** Works and echos glue\router **/
$router = new router();
/** Don't do nothing **/
$cheese = F($email);

Answer 1

Here's the only right answer.
Every namespace needs its own spl_autoload_register() function.
also, spl_autoload_register() syntax changed in 5.3:
spl_autoload_register(__NAMESPACE__ . "\\className::functionName"));
The following should work:
namespace glue;
require_once 'import.php';
use glue\import as import;
use glue\core\router as router;
$import = new import();
spl_autoload_register(__NAMESPACE__ . "\\$import::load"));
/** Works and echos glue\router **/
$router = new router();
/** Don't do nothing **/
$cheese = \glue\common\is_email($email);
Here is some live code that Just works!
in ../WebPageConsolidator.inc.php:
class WebPageConsolidator
{
public function __construct() { echo "PHP 5.2 constructor.\n"; }
}
in test.php:
<?php
namespace WebPage;
class MyAutoloader
{
public static function load($className)
{
require '../' . __NAMESPACE__ . $className . '.inc.php';
}
}
spl_autoload_register(__NAMESPACE__ . "\\MyAutoloader::load");
class Consolidator extends \WebpageConsolidator
{
public function __construct()
{
echo "PHP 5.3 constructor.\n";
parent::__construct();
}
}
// Output:
// PHP 5.3 constructor.
// PHP 5.2 constructor.
So I know it works.

Answer 2

The misconception in the question of the OP is probably that functions/methods would be subject to autoloading – which they are not. Autoloading is only triggered by referencing classes.
This being said there still remains the question about autoloading classes in namespaces:
As of 2017 the current PHP-FIG standard for autoloading is PSR-4 which provides the following autoloader code for namespaced classes:
<?php
/**
* An example of a project-specific implementation.
*
* After registering this autoload function with SPL, the following line
* would cause the function to attempt to load the \Foo\Bar\Baz\Qux class
* from /path/to/project/src/Baz/Qux.php:
*
* new \Foo\Bar\Baz\Qux;
*
* #param string $class The fully-qualified class name.
* #return void
*/
spl_autoload_register(function ($class) {
// project-specific namespace prefix
$prefix = 'Foo\\Bar\\';
// base directory for the namespace prefix
$base_dir = __DIR__ . '/src/';
// does the class use the namespace prefix?
$len = strlen($prefix);
if (strncmp($prefix, $class, $len) !== 0) {
// no, move to the next registered autoloader
return;
}
// get the relative class name
$relative_class = substr($class, $len);
// replace the namespace prefix with the base directory, replace namespace
// separators with directory separators in the relative class name, append
// with .php
$file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';
// if the file exists, require it
if (file_exists($file)) {
require $file;
}
});
The full spec text can be found at PSR-4: Autoloader.
The code example above (and another one to autoload from multiple namespaces) can be found at Example Implementations of PSR-4 (or GitHub: fig-standards/accepted/PSR-4-autoloader-examples.md).

Answer 3

Use Composer to autoload your PHP Classes.
Check out how to do it in my recent blog post: https://enchanterio.github.io/enterprise-level-php/2017/12/25/the-magic-behind-autoloading-php-files-using-composer.html