Question

I tried to understand this line of code, but it is failed.

$this->request->{self::FLAG_SHOW_CONFIG} === ‘true’

I have no keyword to search for this kind of syntax.

What does it means.

1. How come they have “===” instead of “==” ?

2. How come they can do $this->request->{self::FLAG_SHOW_CONFIG}, while, the FLAG_SHOW_CONFIG is a field of $this, it is not belong to $this-> request

The full code is

<?php
    class Magentotutorial_Configviewer_Model_Observer {
        const FLAG_SHOW_CONFIG = 'showConfig';
        const FLAG_SHOW_CONFIG_FORMAT = 'showConfigFormat';     

        private $request;

        public function checkForConfigRequest($observer) {          
            $this->request = $observer->getEvent()->getData('front')->getRequest();
            if($this->request->{self::FLAG_SHOW_CONFIG} === 'true'){
                $this->setHeader();
                $this->outputConfig();
            }
        }
?>

Answer 1

The $this->request->{self::FLAG_SHOW_CONFIG} is interpreted by PHP as $this->request->showConfig. And the === is basically checking for equality in both value and type. Check this page to see the description of the triple equal signs http://php.net/manual/en/language.operators.comparison.php

Also, check this page http://php.net/manual/en/language.variables.variable.php to see about variable variables in PHP.