Changes the timezone to China (+8)

If you use mysql database, you will also need to use

mysql_query("SET time_zone = '+8:00'");

to change the the timezone of mysql database.

Apache server provides a .htaccess file using which you can use to redirect URLs. For example, if you want to redirect all visitors to http://dallascao.com/cn/ to http://dallascao.com/en/, you can open the .htaccess file at the root, and then input:

RewriteRule ^cn\/?$ en\/

Translating the code in English, it means “Please replace ‘^cn\/?$’ with ‘en/’”. “^cn\/?$” is a regular expression, in which:

“^” matches the beginning of a string.
“$” matches the end.
“\” means “/” following it stands for “/” itself, not part of the grammar.
“?” means there can be one “/” or no “/”

So “^cn\/?$” matches two strings: “cn/” or “cn”. When visitors visit http://dallascao.com/cn/ (end with a slash) or http://dallascao.com/cn (end with no slash), they are redirected to http://dallascao.com/en/

Task two:

If you want to redirect all visitors to the root of http://dallascao.com/ to http://dallascao.com/en/, I can use this:

RewriteRule ^$ en\/

“^$” matches an empty string, meaning the root.

Task three:

Inputting the following code into the .htaccess of http://gt4t.net/, all visitors to http://gt4t.net/anything/ to http://gt4t.net/en/anything/. For example, visitors to http://gt4t.net/downloads/ will be redirected to http://gt4t.net/en/downloads.

RewriteRule ^(.*?)\/?$ \/en\/$1

“^(.*?)\/?$” means anything that either ends with one “/” or no “/”. In the second part, “\/en\/$1″, “$1″ stands for the 1st bracketed element in the previous string “^(.*?)\/?$” (in this case, the only bracketed element.). And it means replacing “ANYTHING” ending with “/” or no “/” with “/en/ANYTHING/”

By the way, if you want your redirection to be hidden, you can add the following option to the beginng .

Options +FollowSymLinks

In the example above, your visitors to http://gt4t.net/downloads is redirected to http://gt4t.net/gt4t_en/downloads/ but http://gt4t.net/downloads is still shown in the address bar.

Finally, here is is the complete .htaccess file:

RewriteEngine on
Options +FollowSymLinks
 
RewriteCond %{HTTP_HOST} ^gt4t.net$ [OR]
RewriteCond %{HTTP_HOST} ^www.gt4t.net$
RewriteRule ^(.*?)\/?$ \/gt4t_en\/$1 [L]

Confused? Contact me if you have such a need. I will be happy to help you.

To do this, you need to edit the header.php of the English version under the /en/ folder and add the following code before the tag:

<!--set permanent cookie -->
<?php 
setcookie("lang", "en", time()+94608000, "/", ".dallascao.com");
?>

This code writes a variable “lang” on your computer and assigns a value “en”. 94608000 is the expiration time (3 years). “/” and “.dallascao.com” means it works from the root directory of dallascao.com and its subdomains. Inserting this code into header.php means that when you visit any page of the English version, your visit will be remembered.

Likewise, you need to insert the following code into the header.php of the Chinese version.

<!--set permanent cookie -->
<?php 
setcookie("lang", "cn", time()+94608000, "/", ".dallascao.com");
?>

It means when you visit the Chinese version, the variable “lang” will be assigned the value of “cn”.

At last, Create an index.php at the root containing the following code.

<?php $lang=$_COOKIE["lang"];
switch ($lang) {
 
case 'cn':
header('Location:  http://dallascao.com/cn');
break;
 
case 'en':
header('Location:  http://dallascao.com/en');
break;
#Get the default language of the browser if no cookies are found.
default:
	$lang = getDefaultLanguage(); 
	switch ($lang) { 
       case 'zh-cn' : 
               header('Location:  http://dallascao.com/cn'); 
               break; 
       default: 
	          header('Location: http://dallascao.com/en'); 
              break; 
		} 
break;
}
?>
 
 
<?php
 
 
 
#########################################################
# Copyright ? 2008 Darrin Yeager                        #
# http://www.dyeager.org/                               #
# Licensed under BSD license.                           #
#   http://www.dyeager.org/downloads/license-bsd.php    #
#########################################################

function getDefaultLanguage() {
   if (isset($_SERVER["HTTP_ACCEPT_LANGUAGE"]))
      return parseDefaultLanguage($_SERVER["HTTP_ACCEPT_LANGUAGE"]);
   else
      return parseDefaultLanguage(NULL);
   }
 
function parseDefaultLanguage($http_accept, $deflang = "en") {
   if(isset($http_accept) && strlen($http_accept) > 1)  {
      # Split possible languages into array
      $x = explode(",",$http_accept);
      foreach ($x as $val) {
         #check for q-value and create associative array. No q-value means 1 by rule
         if(preg_match("/(.*);q=([0-1]{0,1}\.\d{0,4})/i",$val,$matches))
            $lang[$matches[1]] = (float)$matches[2];
         else
            $lang[$val] = 1.0;
      }
 
      #return default language (highest q-value)
      $qval = 0.0;
      foreach ($lang as $key => $value) {
         if ($value > $qval) {
            $qval = (float)$value;
            $deflang = $key;
         }
      }
   }
   return strtolower($deflang);
}
 
 
?>

http://dallascao.com/en/2009/07/the-context-sensitive-language-versions-link/

by clicking “中文” at the bottom, he is taken to

http://dallascao.com/cn/2009/07/the-context-sensitive-language-versions-link/

So it involves replacing the “/en/” the URL of the current page with “/cn/”.

The following php code gives out wrong results:

<?php $url_old = "http://".$_SERVER ['HTTP_HOST'].$_SERVER['PHP_SELF']; ?>
<?php $url_new=str_replace("en","cn",$url_old); ?>   
<a href=<?php echo $url_new; ?>Chinese</a>

Whichever page you are visiting, $url_old always gives the home URL “/en/index.php”. This is because I turned Permalinks on and the URL is rewritten. The URL rewritting takes place after the execution of PHP codes on the server side, and therefore the php string “$url_old” cannot get the actual URL as it is rewritten afterwards. The following java script can get the right current URL as java script runs on the client’s computer:

<script>
var s=window.location.href
r=s.replace (/en/, "cn");
document.write ("<li><a title='English verion of this page' href="+r+">Chinese</a></li>")
</script>

More information:

java replace () method