PHP規範PSR-4的示例實現
阿新 • • 發佈:2018-11-01
以下示例說明了符合PSR-4的程式碼:
1 閉合事例
<?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; } });
2 類事例
以下是處理多個名稱空間的示例類實現:
<?php namespace Example; /** * An example of a general-purpose implementation that includes the optional * functionality of allowing multiple base directories for a single namespace * prefix. * * Given a foo-bar package of classes in the file system at the following * paths ... * * /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 * * ... add the path to the class files for the \Foo\Bar\ namespace prefix * as follows: * * <?php * // instantiate the loader * $loader = new \Example\Psr4AutoloaderClass; * * // register the autoloader * $loader->register(); * * // register the base directories for the namespace prefix * $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/src'); * $loader->addNamespace('Foo\Bar', '/path/to/packages/foo-bar/tests'); * * The following line would cause the autoloader to attempt to load the * \Foo\Bar\Qux\Quux class from /path/to/packages/foo-bar/src/Qux/Quux.php: * * <?php * new \Foo\Bar\Qux\Quux; * * The following line would cause the autoloader to attempt to load the * \Foo\Bar\Qux\QuuxTest class from /path/to/packages/foo-bar/tests/Qux/QuuxTest.php: * * <?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; } }
3 單元測試
以下示例是對上述類載入器進行單元測試的一種方法:
<?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); } }