EventDispatcher Component Usage Example

As I was browsing through Composer packages on Packagist I came across the EventDispatcher component from the Symfony framework, which can be used independent of Symfony (I believe all components of Symfony are now modular).

The EventDispatcher component allows you to adopt the observer pattern – events/listeners, events/observers (Magento and others), actions/hooks (WordPress), etc. They all follow the same basic pattern but have different implementations.

Once you run composer require symfony/event-dispatcher in your project’s directory you’ll be ready to try it out. If you’re not familiar with Composer, get acquainted now. I don’t think we’d be having a PHP revolution without it.

I’ve put together a simple but complete example of how it can be used in the following Gist:

Note: Adjust the path to autoload.php as needed.

Loose comparisons with ==

My ZCE studies didn’t expose me to these edge cases, well except for the first one.

If you use == watch out for these and related:

<?php
echo ((0 == 'hello') ? 'true' : 'false').PHP_EOL; //true
echo ((0 == '1hello') ? 'true' : 'false').PHP_EOL; //false
echo (('0' == '0e0') ? 'true' : 'false').PHP_EOL; //true
echo (('0' == '0e0e') ? 'true' : 'false').PHP_EOL; //false
echo (('0' == '0ee') ? 'true' : 'false').PHP_EOL; //false
echo ((0 == '0x0') ? 'true' : 'false').PHP_EOL; //true
echo ((0 == '0x0x') ? 'true' : 'false').PHP_EOL; //true
echo ((0 == '0x0b') ? 'true' : 'false').PHP_EOL; //false
?>

Whoa, we don’t want any of these to return true, what’s a developer to do?

Strict comparisons with ===

<?php
echo ((0 === 'hello') ? 'true' : 'false').PHP_EOL; //false
echo ((0 === '1hello') ? 'true' : 'false').PHP_EOL; //false
echo (('0' === '0e0') ? 'true' : 'false').PHP_EOL; //false
echo (('0' === '0e0e') ? 'true' : 'false').PHP_EOL; //false
echo (('0' === '0ee') ? 'true' : 'false').PHP_EOL; //false
echo ((0 === '0x0') ? 'true' : 'false').PHP_EOL; //false
echo ((0 === '0x0x') ? 'true' : 'false').PHP_EOL; //false
echo ((0 === '0x0b') ? 'true' : 'false').PHP_EOL; //false
?>

Much better.

Learn more at http://php.net/manual/en/types.comparisons.php

Escape HTML Function for Browser Output Prevents XSS (Cross-Site Scripting)

I don’t know about you but my fingers get tired of escaping output by typing the long-winded htmlspecialchars($str, ENT_QUOTES, 'UTF-8'); over and over again in small PHP projects that don’t need a full-blown framework with automatic output filtering (e.g. CodeIgniter). No matter how small your project is though filtering your output is extremely important so that you prevent malicious users from executing XSS (Cross-Site Scripting) JavaScript code.

So I decided to give my fingers some relief and finally write a short little helper function and share it. See the code and example in the gist below.

Highly Secure Data Encryption & Decryption Made Easy with PHP, MCrypt, Rijndael-256, and CBC

Random hexadecimal codes on a computer monitor.  Shallow depth of field.In various projects in the past I’ve had to revisit the topic of data encryption and decryption and the best way to accomplish it. In the interest of developing in the simplest, most efficient, and most secure way I have choosen the MCrypt PHP library (built-in to PHP since v4.0.2), Rijndael-256 cipher, and the Cipher Block Chaining (CBC) mode.

Previously I have used the Electronic CodeBook (ECB) mode, but have learned that it is far less secure than CBC because it creates the same hash every time for the same source data. CBC on the other hand creates a unique hash every time even for the same source data.

Anyways, below you’ll find my revised encrypt/decrypt functions with support for all PHP data types. [Read more…]