Reflection-In-PHP

Reflection in PHP
Presenter: Deepak Rai, Mindfire Solutions
Date: 30/06/2014

About me:
Skills:
PHP, MySQL, JavaScript, jQuery, HTML, CSS CodeIgniter,
StoredProcedures, SVN, GIT.
Certifications:
– Oracle Certified Professional (OCP) MySQL
– Oracle Certified Associate (OCA) MySQL
– Microsoft Certified HTML5, CSS3 and Javascript programmer
Contact me:
Skype: mfsi_deepakr
E-mail: deepakr@mindfiresolutions.com
Facebook: www.facebook.com/deepakrai89
LinkedIn: https://www.linkedin.com/in/deepakrai89
Google Plus: https://plus.google.com/114288591774549019180/
Twitter: www.twitter.com/__deepakrai

Agenda
– Introduction to PHP Reflection API
– How to use it from command line
– Different classes available in API
– How to get more information about a Class or a Method using this API
– Examples of creating HTML Forms and Database tables
– Different PHP well known frameworks using this API
– Benefits of using Reflection API

What is Reflection in Programming
Languages ?
Reflection is generally defined as a program's ability to inspect
itself and modify its logic at execution time. In less technical
terms, reflection is asking an object to tell you about its
properties and methods, and altering those members.

Using Reflection API from command line
$ php --rf strlen
Function [ <internal:Core> function strlen ] {
- Parameters [1] {
Parameter #0 [ <required> $str ]
}
}
$ php --rf array_merge
Function [ <internal:standard> function array_merge ] {
- Parameters [3] {
Parameter #0 [ <required> $arr1 ]
Parameter #1 [ <required> $arr2 ]
Parameter #2 [ <optional> $... ]
}
}

Classes available in PHP Reflection API
Class Name Description
ReflectionClass Gives information about a class
ReflectionFunction Reports information about a function
ReflectionMethod Reports information about a method
ReflectionParameter Retrives information about method's or
function's parameter
ReflectionProperty Gives information about a properties
ReflectionObject Gives information about an object
Few more classes are available in Reflection API apart from above mentioned.

Methods available in PHP “ReflectionClass”
Class
Method Name Description
getProperties Gets all properites of the class
getMethods Gets all methods of the class
getDocComment Get Class Document comment
getFileName Gets the file name of the file in which the class
has been defined
getParentClass Gets parent class
hasMethod Checks if method is defined
ReflectionClass has a long list of methods.

Using 'ReflectionClass' class to get class
information
<?php
class myClass{
public $var;
. . .
public function myFun(){
. . .
}
}
$myClassObj = new myClass();
$myClassRef = new ReflectionClass($myClassObj);
print_r($myClassRef);
print_r($myClassRef->getProperties());
print_r($myClassRef->getMethods());
ReflectionClass Object
(
[name] => myClass
)
Array
(
[0] => ReflectionProperty Object
(
[name] => var
[class] => myClass
)
)
Array
(
[0] => ReflectionMethod Object
(
[name] => myFun
[class] => myClass
)
)

Using 'ReflectionMethod' class to get a
method information
class sumClass{
/**
* @access public
* @var $a
* @var $b
*/
public function setNum($a, $b = 5){
. . .
. . .
}
}
$sumObj = new sumClass();
$setNumMethodReflection = new
ReflectionMethod($sumObj, 'setNum');
print_r($setNumMethodReflection);
echo $setNumMethodReflection;
/**
* @access public
* @var $a
* @var $b
*/
Method [ <user> public method setNum ] {
@@
/home/deepak/Desktop/ReflectionPHP/ReflectionMeth
odExample.php 25 - 31
- Parameters [2] {
Parameter #0 [ <required> $a ]
Parameter #1 [ <optional> $b = 5 ]
}
}

Applications
of PHP Reflection
API

Generating HTML form from a PHP class
In Models, generally a Model class represents a DB table for which data is taken by HTML
form
class Person {
private $first_name;
private $last_name;
private $age;
private $email;
/**
* Set first name
*/
public function set_first_name($first_name){
$this->first_name = $first_name;
}
/**
* Set last name
*/
public function set_last_name($last_name){
$this->last_name = $last_name;
}
/**
* Set age
*/
public function set_age($age){
$this->age = $age;
}
/**
* Set email
*/
public function set_email($email){
$this->email = $email;
}
}

Generating HTML form from a PHP class
In Models, generally a Model class represents a DB table for which data is taken by
HTML form (continued..)
// include the class
require_once 'Person.php';
$person_reflection = new ReflectionClass('Person');
// get all methods of Class 'Person'
$person_methods = $person_reflection->getMethods();
// output html form
create_html_form($person_methods);
function create_html_form($person_methods){
/* loop through each method and create html element for each setter method */
foreach($person_methods as $method){
$method_name = $method->getName();
/* if method name prefix is 'set_' the create form element */
if(strpos($method_name, 'set_') !== FALSE){
echo '<label for="'.substr($method_name,4).'">'
.str_replace('_',' ',substr($method_name,4))
.'</label>';echo "<br/>";
echo '<input type="text" name="'.substr($method_name,4).'" />';
echo "<br/>";
}
}
}

Creating DB Table from PHP Class
<?php
/**
* @table="task"
*/
class Task
{
/**
* @Column(type="int", strategy="auto")
*/
protected $id;
/**
* @Column(type="text")
*/
protected $taskDescription;
/**
* @Column(type="date")
*/
protected $dueDate;
}
We can create Database tables using
PHP reflection API.
We can read Class and Properties Doc
comments to filter it out to extract the
useful information like table name
So, here table name is task. Columns
are id, taskDescription and dueDate

PHP Class Documentation Tool
We can use PHP Reflection API to generate
documentation of any PHP class.
DEMO

PHP Frameworks using PHP API
- PHPUnit Framework.
- Code Analysis frameworks (RIPS, a source code analyser).
- CakePHP (AclExtra library uses Reflection API to find all controllers and
methods).
- Laravel uses Reflection API for dependency injection.
- Doctrine ORM uses Reflection API for working with the entities.

Benefits of using Reflection
- Duck typing is not possible with Reflection API.
- HTML Form Generation.
- Creating DB Tables.
- Creating Documentation of poorly documented 3rd party classes.
- Accessing private properties and methods.

?

Thank you

www.mindfiresolutions.com
https://www.facebook.com/MindfireSolutions
http://www.linkedin.com/company/mindfire-solutions
http://twitter.com/mindfires

References:
PHP Manual - http://php.net/manual/en/intro.reflection.php
TutsPlus - http://code.tutsplus.com/tutorials/reflection-in-php--net-31408

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