# Let’s talk about the application of reflection in actual development.
- Automatically generate documents
- Implement MVC architecture
- Implement unit testing
- Cooperate with DI container to resolve dependencies
- …
Automatically generate documents
Documents can be automatically generated based on the reflection analysis of classes, interfaces, internal structures of functions and methods, parameters of methods and functions, and attributes and methods of classes.
/**
* 学生类
*
* 描述信息
*/
class Student
{
const NORMAL = 1;
const FORBIDDEN = 2;
/**
* 用户ID
* @var 类型
*/
public $id;
/**
* 获取id
* @return int
*/
public function getId()
{
return $this->id;
}
public function setId($id = 1)
{
$this->id = $id;
}
}
$ref = new ReflectionClass('Student');
$doc = $ref->getDocComment();
echo $ref->getName() . ':' . getComment($ref) , "\n";
echo "属性列表：\n";
printf("%-15s%-10s%-40s\n", 'Name', 'Access', 'Comment');
$attr = $ref->getProperties();
foreach ($attr as $row) {
printf("%-15s%-10s%-40s\n", $row->getName(), getAccess($row), getComment($row));
}
echo "常量列表：\n";
printf("%-15s%-10s\n", 'Name', 'Value');
$const = $ref->getConstants();
foreach ($const as $key => $val) {
printf("%-15s%-10s\n", $key, $val);
}
echo "\n\n";
echo "方法列表\n";
printf("%-15s%-10s%-30s%-40s\n", 'Name', 'Access', 'Params', 'Comment');
$methods = $ref->getMethods();
foreach ($methods as $row) {
printf("%-15s%-10s%-30s%-40s\n", $row->getName(), getAccess($row), getParams($row), getComment($row));
}
// 获取权限
function getAccess($method)
{
if ($method->isPublic()) {
return 'Public';
}
if ($method->isProtected()) {
return 'Protected';
}
if ($method->isPrivate()) {
return 'Private';
}
}
// 获取方法参数信息
function getParams($method)
{
$str = '';
$parameters = $method->getParameters();
foreach ($parameters as $row) {
$str .= $row->getName() . ',';
if ($row->isDefaultValueAvailable()) {
$str .= "Default: {$row->getDefaultValue()}";
}
}
return $str ? $str : '';
}
// 获取注释
function getComment($var)
{
$comment = $var->getDocComment();
// 简单的获取了第一行的信息，这里可以自行扩展
preg_match('/\* (.*) *?/', $comment, $res);
return isset($res[1]) ? $res[1] : '';
}Run php file.php to see the corresponding document information.
Implementing the MVC architecture
Many frameworks now have the MVC architecture. Locate the names of the controller ($controller) and the method ($method) based on the routing information, and then Use reflection to implement automatic calling.
$class = new ReflectionClass(ucfirst($controller) . 'Controller');
$controller = $class->newInstance();
if ($class->hasMethod($method)) {
$method = $class->getMethod($method);
$method->invokeArgs($controller, $arguments);
} else {
throw new Exception("{$controller} controller method {$method} not exists!");
}
class Calc
{
public function plus($a, $b)
{
return $a + $b;
}
public function minus($a, $b)
{
return $a - $b;
}
}
function testEqual($method, $assert, $data)
{
$arr = explode('@', $method);
$class = $arr[0];
$method = $arr[1];
$ref = new ReflectionClass($class);
if ($ref->hasMethod($method)) {
$method = $ref->getMethod($method);
$res = $method->invokeArgs(new $class, $data);
var_dump($res === $assert);
}
}
testEqual('Calc@plus', 3, [1, 2]);
testEqual('Calc@minus', -1, [1, 2]);Here is just a test case I simply wrote.
PHPUnit The unit testing framework relies heavily on the features of Reflection, you can learn more about it.
Laravel Many frameworks such as Reflection are used to solve dependency injection problems. For details, please see Laravel Source code for analysis. Below our code simply implements a
DI container demonstration Reflection to solve the dependency injection problem.
class DI
{
protected static $data = [];
public function __set($k, $v)
{
self::$data[$k] = $v;
}
public function __get($k)
{
return $this->bulid(self::$data[$k]);
}
// 获取实例
public function bulid($className)
{
// 如果是匿名函数，直接执行，并返回结果
if ($className instanceof Closure) {
return $className($this);
}
// 已经是实例化对象的话，直接返回
if(is_object($className)) {
return $className;
}
// 如果是类的话，使用反射加载
$ref = new ReflectionClass($className);
// 监测类是否可实例化
if (!$ref->isInstantiable()) {
throw new Exception('class' . $className . ' not find');
}
// 获取构造函数
$construtor = $ref->getConstructor();
// 无构造函数，直接实例化返回
if (is_null($construtor)) {
return new $className;
}
// 获取构造函数参数
$params = $construtor->getParameters();
// 解析构造函数
$dependencies = $this->getDependecies($params);
// 创建新实例
return $ref->newInstanceArgs($dependencies);
}
// 分析参数，如果参数中出现依赖类，递归实例化
public function getDependecies($params)
{
$data = [];
foreach($params as $param)
{
$tmp = $param->getClass();
if (is_null($tmp)) {
$data[] = $this->setDefault($param);
} else {
$data[] = $this->bulid($tmp->name);
}
}
return $data;
}
// 设置默认值
public function setDefault($param)
{
if ($param->isDefaultValueAvailable()) {
return $param->getDefaultValue();
}
throw new Exception('no default value!');
}
}
class Demo
{
public function __construct(Calc $calc)
{
echo $calc->plus(1, 2);
}
}
$di = new DI();
$di->calc = 'Calc'; // 加载单元测试用例中 Calc 类
$di->demo = 'Demo';
$di->demo;calc and demo above cannot be reversed, otherwise an error will be reported. The reason is that Demo depends on Calc , first define dependencies. When
Demo is instantiated, the Calc class will be used, which means Demo depends on Calc, but in $data If the above is not found, an error will be thrown, so first define . Reflection is a very cool feature, use it, but don't abuse it.
End
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