PSR-4 实例
以下是一个实现PSR-4规范的例子：
Closure Example
<?php
/** * 一个具体项目实现的例子. * 使用SPL注册了autoload函数之后，以下代码将触发autoload函数从 * /path/to/project/src/Baz/Qux.php 文件加载 * \Foo\Bar\Baz\Qux 类 * new \Foo\Bar\Baz\Qux; * * @param string $class The fully-qualified class name. * @return void */
spl_autoload_register(function ($class) {
// 项目约定的命名空间前缀
$prefix = 'Foo\\Bar\\';
// 命名空间前缀的基础目录
$base_dir = __DIR__ . '/src/';
// 这个类是否使用了命名空间前缀?
$len = strlen($prefix);
if (strncmp($prefix, $class, $len) !== 0) {
// 没有，尝试下个已注册的 autoloader
return;
}
// 获取相对类名（截取命名空间前缀后剩下的部分）
$relative_class = substr($class, $len);
// 用base目录替换命名空间前缀；
// 用目录分隔符替换命名空间分隔符；
// 坠上 .php
$file = $base_dir . str_replace('\\', '/', $relative_class) . '.php';
// 如果文件存在，加载文件。
if (file_exists($file)) {
require $file;
}
});Class Example
以下是一个处理多命名空间的类的例子。
<?php
namespace Example;
/** * 这个例子是一个针对 一个命名空间前缀对应多个base谬的通用实现。 * * foo-bar 类的包分别在以下路径下... * * /path/to/packages/foo-bar/ * src/ * Baz.php # Foo\Bar\Baz * Qux/ * Quux.php # Foo\Bar\Qux\Quux * tests/ * BazTest.php # Foo\Bar\BazTest * Qux/ * QuuxTest.php # Foo\Bar\Qux\QuuxTest * * ... 以下代码将类文件的路径添加到 \Foo\Bar\命名空间前缀下。 * * <?php * // 初始化 loader * $loader = new \Example\Psr4AutoloaderClass; * * // 注册 autoloader * $loader->register(); * * // 为命名空间前缀注册base目录。 * $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/src'); * $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/tests'); * * 下面的代码将触发 autoloader 尝试从 * /path/to/packages/foo-bar/src/Qux/Quux.php 加载 * \Foo\Bar\Qux\Quux 类: * * <?php * new \Foo\Bar\Qux\Quux; * * 以下代码触发autoloader尝试从 * /path/to/packages/foo-bar/tests/Qux/QuuxTest.php * 加载\Foo\Bar\Qux\QuuxTest类 : * * <?php * new \Foo\Bar\Qux\QuuxTest; */
class Psr4AutoloaderClass {
/** * An associative array where the key is a namespace prefix and the value * is an array of base directories for classes in that namespace. * * @var array */
protected $prefixes = array();
/** * Register loader with SPL autoloader stack. * * @return void */
public function register() {
spl_autoload_register(array($this, 'loadClass'));
}
/** * Adds a base directory for a namespace prefix. * * @param string $prefix The namespace prefix. * @param string $base_dir A base directory for class files in the * namespace. * @param bool $prepend If true, prepend the base directory to the stack * instead of appending it; this causes it to be searched first rather * than last. * @return void */
public function addNamespace($prefix, $base_dir, $prepend = false) {
// normalize namespace prefix
$prefix = trim($prefix, '\\') . '\\';
// normalize the base directory with a trailing separator
$base_dir = rtrim($base_dir, DIRECTORY_SEPARATOR) . '/';
// initialize the namespace prefix array
if (isset($this->prefixes[$prefix]) === false) {
$this->prefixes[$prefix] = array();
}
// retain the base directory for the namespace prefix
if ($prepend) {
array_unshift($this->prefixes[$prefix], $base_dir);
} else {
array_push($this->prefixes[$prefix], $base_dir);
}
}
/** * Loads the class file for a given class name. * * @param string $class The fully-qualified class name. * @return mixed The mapped file name on success, or boolean false on * failure. */
public function loadClass($class) {
// the current namespace prefix
$prefix = $class;
// work backwards through the namespace names of the fully-qualified
// class name to find a mapped file name
while (false !== $pos = strrpos($prefix, '\\')) {
// retain the trailing namespace separator in the prefix
$prefix = substr($class, 0, $pos + 1);
// the rest is the relative class name
$relative_class = substr($class, $pos + 1);
// try to load a mapped file for the prefix and relative class
$mapped_file = $this->loadMappedFile($prefix, $relative_class);
if ($mapped_file) {
return $mapped_file;
}
// remove the trailing namespace separator for the next iteration
// of strrpos()
$prefix = rtrim($prefix, '\\');
}
// never found a mapped file
return false;
}
/** * Load the mapped file for a namespace prefix and relative class. * * @param string $prefix The namespace prefix. * @param string $relative_class The relative class name. * @return mixed Boolean false if no mapped file can be loaded, or the * name of the mapped file that was loaded. */
protected function loadMappedFile($prefix, $relative_class) {
// are there any base directories for this namespace prefix?
if (isset($this->prefixes[$prefix]) === false) {
return false;
}
// look through base directories for this namespace prefix
foreach ($this->prefixes[$prefix] as $base_dir) {
// 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('\\', '/', $relative_class)
. '.php';
// if the mapped file exists, require it
if ($this->requireFile($file)) {
// yes, we're done
return $file;
}
}
// never found it
return false;
}
/** * If a file exists, require it from the file system. * * @param string $file The file to require. * @return bool True if the file exists, false if not. */
protected function requireFile($file) {
if (file_exists($file)) {
require $file;
return true;
}
return false;
}
}Unit Tests
The following example is one way of unit testing the above class loader:
<?php
namespace Example\Tests;
class MockPsr4AutoloaderClass extends Psr4AutoloaderClass {
protected $files = array();
public function setFiles(array $files) {
$this->files = $files;
}
protected function requireFile($file) {
return in_array($file, $this->files);
}
}
class Psr4AutoloaderClassTest extends \PHPUnit_Framework_TestCase {
protected $loader;
protected function setUp() {
$this->loader = new MockPsr4AutoloaderClass;
$this->loader->setFiles(array(
'/vendor/foo.bar/src/ClassName.php',
'/vendor/foo.bar/src/DoomClassName.php',
'/vendor/foo.bar/tests/ClassNameTest.php',
'/vendor/foo.bardoom/src/ClassName.php',
'/vendor/foo.bar.baz.dib/src/ClassName.php',
'/vendor/foo.bar.baz.dib.zim.gir/src/ClassName.php',
));
$this->loader->addNamespace(
'Foo\Bar',
'/vendor/foo.bar/src'
);
$this->loader->addNamespace(
'Foo\Bar',
'/vendor/foo.bar/tests'
);
$this->loader->addNamespace(
'Foo\BarDoom',
'/vendor/foo.bardoom/src'
);
$this->loader->addNamespace(
'Foo\Bar\Baz\Dib',
'/vendor/foo.bar.baz.dib/src'
);
$this->loader->addNamespace(
'Foo\Bar\Baz\Dib\Zim\Gir',
'/vendor/foo.bar.baz.dib.zim.gir/src'
);
}
public function testExistingFile() {
$actual = $this->loader->loadClass('Foo\Bar\ClassName');
$expect = '/vendor/foo.bar/src/ClassName.php';
$this->assertSame($expect, $actual);
$actual = $this->loader->loadClass('Foo\Bar\ClassNameTest');
$expect = '/vendor/foo.bar/tests/ClassNameTest.php';
$this->assertSame($expect, $actual);
}
public function testMissingFile() {
$actual = $this->loader->loadClass('No_Vendor\No_Package\NoClass');
$this->assertFalse($actual);
}
public function testDeepFile() {
$actual = $this->loader->loadClass('Foo\Bar\Baz\Dib\Zim\Gir\ClassName');
$expect = '/vendor/foo.bar.baz.dib.zim.gir/src/ClassName.php';
$this->assertSame($expect, $actual);
}
public function testConfusion() {
$actual = $this->loader->loadClass('Foo\Bar\DoomClassName');
$expect = '/vendor/foo.bar/src/DoomClassName.php';
$this->assertSame($expect, $actual);
$actual = $this->loader->loadClass('Foo\BarDoom\ClassName');
$expect = '/vendor/foo.bardoom/src/ClassName.php';
$this->assertSame($expect, $actual);
}
}