Call method by string?

Question

Class MyClass{
  private $data=array('action'=>'insert');
  public function insert(){
    echo 'called insert';
  }

  public function run(){
    $this->$this->data['action']();
  }
}

This doesn't work:

$this->$this->data['action']();

Is the only possibility to use call_user_func();?

Mārtiņš Briedis · Accepted Answer · 2022-11-29 16:59:28Z

138

Try:

$this->{$this->data['action']}();

Be sure to check if the action is allowed and it is callable


<?php

$action = 'myAction';

// Always use an allow-list approach to check for validity
$allowedActions = [
    'myAction',
    'otherAction',
];

if (!in_array($action, $allowedActions, true)) {
    throw new Exception('Action is not allowed');
}

if (!is_callable([$this, $action])) {
    // Throw an exception or call some other action, e.g. $this->default()
    throw new Exception('Action is not callable');
}

// At this point we know it's an allowed action, and it is callable
$this->$action();

edited Nov 29, 2022 at 16:59

answered Mar 27, 2011 at 18:38

Mārtiņš Briedis

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5 Comments

Jesse Bunch Over a year ago

Be sure to check if the function exists: function_exists() first!

Marek Bar Over a year ago

It works. Should I use any security tricks like function exists or functions allowed array ?

Mārtiņš Briedis Over a year ago

@MarekBar If input comes from user, you should always escape it properly.Ideally, use a white-list with allowed actions.

gagarine Over a year ago

@JesseBunch you don't need to use function_exist if you allready check with is_callable

xDaizu Over a year ago

Worth mentioning that in some versions of PHP, is_callable doesn't respect visibility, as commented in the documentation

Brad Koch · Accepted Answer · 2012-10-08 16:27:46Z

17

Reemphasizing what the OP mentioned, call_user_func() and call_user_func_array() are also good options. In particular, call_user_func_array() does a better job at passing parameters when the list of parameters might be different for each function.

call_user_func_array(
    array($this, $this->data['action']),
    $params
);

answered Oct 8, 2012 at 16:27

Brad Koch

20.5k21 gold badges114 silver badges141 bronze badges

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