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How do I add a method to an object in PHP?

Answer 1

+6 A:

A solution would be to create a new class, that extends the one from your library -- and, then, use your class, which have have all methods of the original one, plus yours.

Here's a (very quick and simple) example :

class YourClass extends TheLibraryClass {
  public function yourNewMethod() {
    // do what you want here
  }
}

And, then, you use your class :

$obj = new YourClass();
$obj->yourNewMethod();

And you can call the methods of the TheLibraryClass class, as yours inherits the properties and methods of that one :

$obj->aMethodFromTheLibrary();

About that, you can take a look at the Object Inheritance section of the manual.

And, as you guessed, modifying a library is definitly a bad idea : you'll have to re-do that modification each time you update the library !

(One day or another, you'll forget -- or one of your colleagues will forget ^^ )

Pascal MARTIN 2010-01-27 17:32:09

Thanks, still having issues, made an edit above. Honestly just dropping my method into the source works but I'd like to do it "right" if I can.

Stomped 2010-01-27 17:47:44

Answer 2

A:

I don't why adding the method would be bad, however if you want to so without editing the library, your best bet would be to extend the class like so:

class NewClass extends OldClass {

  function newMethod() {
    //do stuff
  }

}

GSto 2010-01-27 17:33:12

Adding the method is bad because if you update the library, or the library changes its internal implementation, you are very apt to have compatibility issues.

Chacha102 2010-01-27 17:34:05

Yep, but I can't get this to work by extending the class, so far. Hopefully someone can help based on my edits.

Stomped 2010-01-27 17:57:35

Answer 3

+1 A:

class myExtenstionClass extends SomeClassInLibrary
{

  public function myMethod()
  {
     // your function definition
  }
}

As Pascal suggests... read the manual :-)

prodigitalson 2010-01-27 17:34:39

Answer 4

+2 A:

You could do it with inheritance, but you could also use a decorator pattern if you do not need access to any protected members from SimpleHtml. This is a somewhat more flexible approach. See the linked page for details.

class MySimpleHtmlExtension
{
     protected $_dom;

     public function __construct(simple_html_dom $simpleHtml)
     {
         $this->_dom = $simpleHtml;
     }

     public function removeNode(simple_html_dom_node $node)
     {
         $node->outertext = '';
         return $this;
     }

     public function __call($method, $args)
     {
         if(method_exists($this->_dom, $method)) {
             return call_user_func_array(array($this->_dom , $method), $args));
         }
         throw new BadMethodCallException("$method does not exist");
     }

}

You'd use the above like this

$ext = new MySimpleHtmlExtension( new simple_html_dom );
$ext->load('<html><body>Hello <span>World</span>!</body></html>');
$ext->removeNode( $ext->find('span', 0) );

Gordon 2010-01-27 18:19:00

Here's the problem - the method actually gets called on a `simple_dom_html_node` object - which is created by the `simple_dom_html` object. I don't think there's a solution.

Stomped 2010-01-27 22:47:42

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