Magento: Browser detection to load right language - .htaccess

Question

How do I implement a browser detection into Magento to load the right language.
Example:
If a US User is surfing to my Magento shop, Magento should load the path: ..myshop../usa/
usa=storecode
If a japanese User is surfing to my Magento shop, Magento should load the path: ..myshop../jp/
jp=storecode
and so on
I guess I have to adapt the .htaccess with rewrite Urls, but I never did that before. How do I have to do it?
How does the code of browser detection look like and where do I have to put it? In the header.phtml?
thank you very very much in advance!
Edit:
index.php in CE 1.7.0.2 looks like this
/**
* Error reporting
*/
error_reporting(E_ALL | E_STRICT);
/**
* Compilation includes configuration file
*/
define('MAGENTO_ROOT', getcwd());
$compilerConfig = MAGENTO_ROOT . '/includes/config.php';
if (file_exists($compilerConfig)) {
include $compilerConfig;
}
$mageFilename = MAGENTO_ROOT . '/app/Mage.php';
$maintenanceFile = 'maintenance.flag';
if (!file_exists($mageFilename)) {
if (is_dir('downloader')) {
header("Location: downloader");
} else {
echo $mageFilename." was not found";
}
exit;
}
if (file_exists($maintenanceFile)) {
include_once dirname(__FILE__) . '/errors/503.php';
exit;
}
require_once $mageFilename;
#Varien_Profiler::enable();
if (isset($_SERVER['MAGE_IS_DEVELOPER_MODE'])) {
Mage::setIsDeveloperMode(true);
}
#ini_set('display_errors', 1);
umask(0);
/* Store or website code */
$mageRunCode = isset($_SERVER['MAGE_RUN_CODE']) ? $_SERVER['MAGE_RUN_CODE'] : '';
/* Run store or run website */
$mageRunType = isset($_SERVER['MAGE_RUN_TYPE']) ? $_SERVER['MAGE_RUN_TYPE'] : 'store';
Mage::run($mageRunCode, $mageRunType);
But this Link describes the follwing code which you cannot simply replace:
require_once 'app/Mage.php';
/* Determine correct language store based on browser */
function getStoreForLanguage()
{
if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
foreach (explode(",", strtolower($_SERVER['HTTP_ACCEPT_LANGUAGE'])) as $accept) {
if (preg_match("!([a-z-]+)(;q=([0-9.]+))?!", trim($accept), $found)) {
$langs[] = $found[1];
$quality[] = (isset($found[3]) ? (float) $found[3] : 1.0);
}
}
// Order the codes by quality
array_multisort($quality, SORT_NUMERIC, SORT_DESC, $langs);
// get list of stores and use the store code for the key
$stores = Mage::app()->getStores(false, true);
// iterate through languages found in the accept-language header
foreach ($langs as $lang) {
$lang = substr($lang,0,2);
if (isset($stores[$lang]) && $stores[$lang]->getIsActive()) return $stores[$lang];
}
}
return Mage::app()->getStore();
}
/* Auto redirect to language store view if request is for root */
if ($_SERVER['REQUEST_URI'] === '/') {
header('Location: '.getStoreForLanguage()->getBaseUrl());
exit;
}
#Varien_Profiler::enable();
#Mage::setIsDeveloperMode(true);
#ini_set('display_errors', 1);
umask(0);
Mage::run();
Can anybody help me to find out where to put it or where to adapt the index.php
Thank you again!

Answer 1

The request the browser sends has a field called "Accept-Language" header. It's formatting isn't so intuitive and if you wanted to do it correctly, is beyond the ability of the htaccess file and mod_rewrite to parse properly. Here's a typical "Accept-Language" request header:
Accept-Language: da, en-gb;q=0.8, en;q=0.7
Which means: "I prefer Danish, but will accept British English and other types of English"
So you can't simply look for the first two letters of the field. If you don't have Danish, then you've got to continue parsing to find the right language. Magento probably has some ways of dealing with this, for example: http://www.magentocommerce.com/wiki/multi-store_set_up/how_to_automatically_redirect_to_a_store_view_based_on_the_browser_language

Answer 2

Just paste the following code after require_once $mageFilename; in your CE 1.7.0.2 index.php:
/* Determine correct language store based on browser */
function getStoreForLanguage()
{
if (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
foreach (explode(",", strtolower($_SERVER['HTTP_ACCEPT_LANGUAGE'])) as $accept) {
if (preg_match("!([a-z-]+)(;q=([0-9.]+))?!", trim($accept), $found)) {
$langs[] = $found[1];
$quality[] = (isset($found[3]) ? (float) $found[3] : 1.0);
}
}
// Order the codes by quality
array_multisort($quality, SORT_NUMERIC, SORT_DESC, $langs);
// get list of stores and use the store code for the key
$stores = Mage::app()->getStores(false, true);
// iterate through languages found in the accept-language header
foreach ($langs as $lang) {
$lang = substr($lang,0,2);
if (isset($stores[$lang]) && $stores[$lang]->getIsActive()) return $stores[$lang];
}
}
return Mage::app()->getStore();
}
/* Auto redirect to language store view if request is for root */
if ($_SERVER['REQUEST_URI'] === '/') {
header('Location: '.getStoreForLanguage()->getBaseUrl());
exit;
}
Make sure you don't delete or overwrite any code in your index.php file and you should be fine!