Detailed explanation of php Reflection reflection mechanism example

PHP5 adds a new feature: Reflection. This feature allows programmers to

reverse-engineer [reverse engineering] class, interface, function, method and extension [extension library support].

Through PHP code, you can get all the information of an object and interact with it.

Assume the following Person class:

class Person {
    /**
     * For the sake of demonstration, we"re setting this private
     */
    private $_allowDynamicAttributes = false;
    
    /**
     * type=primary_autoincrement
     */
    protected $id = 0;
    
    /**
     * type=varchar length=255 null
     */
    protected $name;
    
    /**
     * type=text null
     */
    protected $biography;
    public function getId() {
        return $this->id;
    }
    public function setId($v) {
        $this->id = $v;
    }
    public function getName() {
        return $this->name;
    }
    public function setName($v) {
        $this->name = $v;
    }
    public function getBiography() {
        return $this->biography;
    }
    public function setBiography($v) {
        $this->biography = $v;
    }
}

Through ReflectionClass, we can get the following information of the Person class:

• Constant Contents

• Property Property Names

• Method Names

• Static PropertiesStatic Properties

• Namespace Namespace

• Whether the Person class is final or abstract

Just put the class name "Person" Just pass it to ReflectionClass:

 $class = new ReflectionClass('Person');

* Get the properties (Properties):

##

$properties = $class->getProperties();
foreach($properties as $property) {
    echo $property->getName()."\n";
}
// 输出:
// _allowDynamicAttributes
// id
// name
// biography

By default, ReflectionClass will get To all attributes, private and protected are also available. If you only want to get the private attribute, you need to pass an additional parameter:

 $private_properties = $class->getProperties(ReflectionProperty::IS_PRIVATE);

Available parameter list:

• ReflectionProperty:: IS_STATIC

• ReflectionProperty::IS_PUBLIC

• ReflectionProperty::IS_PROTECTED

• ReflectionProperty::IS_PRIVATE

If you want to get both public and private properties, just write like this: ReflectionProperty::IS_PUBLIC | ReflectionProperty::IS_PROTECTED

Can be obtained through $property->getName() Property name, the comment written to the property can be obtained through getDocComment.

foreach($properties as $property) {
    if($property->isProtected()) {
        $docblock = $property->getDocComment();
        preg_match('/ type\=([a-z_]*) /', $property->getDocComment(), $matches);
        echo $matches[1]."\n";
    }
}
// Output:
// primary_autoincrement
// varchar
// text

It’s a bit incredible. You can even get comments.

* Get methods (methods): Get all methods of the class through getMethods(). What is returned is an array of ReflectionMethod objects.

No more demonstration.

* Finally, call the method in the class through ReflectionMethod.

$data = array("id" => 1, "name" => "Chris", "biography" => "I am am a PHP developer");
foreach($data as $key => $value) {
    if(!$class->hasProperty($key)) {
        throw new Exception($key." is not a valid property");
    }
 
    if(!$class->hasMethod("get".ucfirst($key))) {
        throw new Exception($key." is missing a getter");
    }
 
    if(!$class->hasMethod("set".ucfirst($key))) {
        throw new Exception($key." is missing a setter");
    }
 
    // Make a new object to interact with
    $object = new Person();
 
    // Get the getter method and invoke it with the value in our data array
    $setter = $class->getMethod("set".ucfirst($key));
    $ok = $setter->invoke($object, $value);
 
    // Get the setter method and invoke it
    $setter = $class->getMethod("get".ucfirst($key));
    $objValue = $setter->invoke($object);
 
    // Now compare
    if($value == $objValue) {
        echo "Getter or Setter has modified the data.\n";
    } else {
        echo "Getter and Setter does not modify the data.\n";
   }
}

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