[magento] Create a simple module to override core functionality

An example of patching cloudflare running Magento server


* Files needed

app/code/local/Fourthmedia/Http/etc/config.xml
app/code/local/Fourthmedia/Http/Helper/Cloudflarehttp.php
app/etc/modules/Fourthmedia_Http.xml



* Example source code


// app/code/local/Fourthmedia/Http/etc/config.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Fourthmedia_Http>
            <version>0.1.0</version>
        </Fourthmedia_Http>
    </modules>
    <global>
        <helpers>
            <core>
                <rewrite>
                    <http>Fourthmedia_Http_Helper_Cloudflarehttp</http>
                </rewrite>
            </core>
        </helpers>
    </global>
</config>


// app/code/local/Fourthmedia/Http/Helper/Cloudflarehttp.php


<?php

class Fourthmedia_Http_Helper_Cloudflarehttp extends Mage_Core_Helper_Http
{
    public function getRemoteAddr($ipToLong = false)
    {
        if (is_null($this->_remoteAddr)) {
            if (isset($_SERVER["HTTP_CF_CONNECTING_IP"])) {
                $this->_remoteAddr = $_SERVER["HTTP_CF_CONNECTING_IP"];
                $this->_remoteAddr = $ipToLong ? inet_pton($this->_remoteAddr) : $this->_remoteAddr;
            } else {
                $this->_remoteAddr = parent::getRemoteAddr(false);
            }
        }

        return $this->_remoteAddr;
    }
}


// app/etc/modules/Fourthmedia_Http.xml

<?xml version="1.0"?>
<config>
    <modules>
        <Fourthmedia_Http>
            <active>true</active>
            <codePool>local</codePool>
        </Fourthmedia_Http>
    </modules>
</config>