今天就跟大家聊聊有关使用PHP编写一个轻量级容器,可能很多人都不太了解,为了让大家更加了解,小编给大家总结了以下内容,希望大家根据这篇文章可以有所收获。
实现示例
实现接口中要求的两个方法
abstract class AbstractContainer implements ContainerInterface { protected $resolvedEntries = []; /** * @var array */ protected $definitions = []; public function __construct($definitions = []) { foreach ($definitions as $id => $definition) { $this->injection($id, $definition); } } public function get($id) { if (!$this->has($id)) { throw new NotFoundException("No entry or class found for {$id}"); } $instance = $this->make($id); return $instance; } public function has($id) { return isset($this->definitions[$id]); }
实际我们容器中注入的对象是多种多样的,所以我们单独抽出实例化方法。
public function make($name) { if (!is_string($name)) { throw new \InvalidArgumentException(sprintf( 'The name parameter must be of type string, %s given', is_object($name) ? get_class($name) : gettype($name) )); } if (isset($this->resolvedEntries[$name])) { return $this->resolvedEntries[$name]; } if (!$this->has($name)) { throw new NotFoundException("No entry or class found for {$name}"); } $definition = $this->definitions[$name]; $params = []; if (is_array($definition) && isset($definition['class'])) { $params = $definition; $definition = $definition['class']; unset($params['class']); } $object = $this->reflector($definition, $params); return $this->resolvedEntries[$name] = $object; } public function reflector($concrete, array $params = []) { if ($concrete instanceof \Closure) { return $concrete($params); } elseif (is_string($concrete)) { $reflection = new \ReflectionClass($concrete); $dependencies = $this->getDependencies($reflection); foreach ($params as $index => $value) { $dependencies[$index] = $value; } return $reflection->newInstanceArgs($dependencies); } elseif (is_object($concrete)) { return $concrete; } } /** * @param \ReflectionClass $reflection * @return array */ private function getDependencies($reflection) { $dependencies = []; $constructor = $reflection->getConstructor(); if ($constructor !== null) { $parameters = $constructor->getParameters(); $dependencies = $this->getParametersByDependencies($parameters); } return $dependencies; } /** * * 获取构造类相关参数的依赖 * @param array $dependencies * @return array $parameters * */ private function getParametersByDependencies(array $dependencies) { $parameters = []; foreach ($dependencies as $param) { if ($param->getClass()) { $paramName = $param->getClass()->name; $paramObject = $this->reflector($paramName); $parameters[] = $paramObject; } elseif ($param->isArray()) { if ($param->isDefaultValueAvailable()) { $parameters[] = $param->getDefaultValue(); } else { $parameters[] = []; } } elseif ($param->isCallable()) { if ($param->isDefaultValueAvailable()) { $parameters[] = $param->getDefaultValue(); } else { $parameters[] = function ($arg) { }; } } else { if ($param->isDefaultValueAvailable()) { $parameters[] = $param->getDefaultValue(); } else { if ($param->allowsNull()) { $parameters[] = null; } else { $parameters[] = false; } } } } return $parameters; }
如你所见,到目前为止我们只实现了从容器中取出实例,从哪里去提供实例定义呢,所以我们还需要提供一个方水法
/** * @param string $id * @param string | array | callable $concrete * @throws ContainerException */ public function injection($id, $concrete) { if (is_array($concrete) && !isset($concrete['class'])) { throw new ContainerException('数组必须包含类定义'); } $this->definitions[$id] = $concrete; }
只有这样吗?对的,有了这些操作我们已经有一个完整的容器了,插箱即用。
不过为了使用方便,我们可以再提供一些便捷的方法,比如数组式访问。
class Container extends AbstractContainer implements \ArrayAccess { public function offsetExists($offset) { return $this->has($offset); } public function offsetGet($offset) { return $this->get($offset); } public function offsetSet($offset, $value) { return $this->injection($offset, $value); } public function offsetUnset($offset) { unset($this->resolvedEntries[$offset]); unset($this->definitions[$offset]); } }
看完上述内容,你们对使用PHP编写一个轻量级容器有进一步的了解吗?如果还想了解更多知识或者相关内容,请关注亿速云行业资讯频道,感谢大家的支持。
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