Internationalization and Routing: adding the language code (en,de,fr) inside URLs

[eluser]Michael Ekoka[/eluser]
language internationalization i18n routing

For those interested in having the current language in the url like this:
http://www.mysite.com/en/my_controller/my_action/var1/var2

I have been playing around with routing and hopefully the time I spent will be worth your while.

You first need to follow a couple of steps in your application's config/routes.php:


1-) You first need to set a regex for the language code that will be prepended to request urls other than the index page. The regex covers the following criteria:
- the language code should be optional
- it should be composed of 2 alphabetical characters
- if added, it must be followed by a slash
e.g. The following urls should point to the same route:
http://www.mysite.com/en/controller/action/var1/var2
http://www.mysite.com/controller/action/var1/var2

In your routes.php file insert this:

Code:

// routes.php
$prepended_lang = "(?:[a-zA-Z]{2}/)?";

2-) You also need a slightly different regex for the language code optionally appended to the index url (www.mysite.com/en) . The criteria covered by that regex:
- the language code should be optional
- it should be composed of 2 alphabetical characters
- if appended to the index, the language code has an optional trailing slash
e.g. the following url should all point to the same route
http://www.mysite.com/
http://www.mysite.com/en
http://www.mysite.com/en/

still in routes.php insert this:

Code:

// routes.php
$appended_lang = "(?:[a-zA-Z]{2}/?)?";

3- Now lets set some routes in routes.php:

Code:

/* routes for controllers */

$route["scaffolding_trigger"] = "some_secret";

// now lets set the routes for the site index
$route["default_controller"] = "index_controller";
$route["$appended_lang"] = "index_controller"; // our index with our optional language code appended

// example of a route with the prepended optional language code
$route["{$prepended_lang}controllerX/actionY(.*)"] = "controllerA/methodB$1";


/**
* routes for controllers inside subfolders
* are similar to routes for normal controllers.
* you just need to add in the subfolder.
**/

$route["{$prepended_lang}subfolder"] = "subfolder/my_controller";
$route["{$prepended_lang}subfolder/controllerX/actionY/(.*)"] = "subfolder/controllerA/methodC/$1";


/**
* Finally you need to define a catchall route for the rest of the site.
* All other routes must come before this one if you want them to be caught.
* It simply remaps the url to the intended destination, whether the language
* code is included or not.
* e.g. the 2 following urls should point to the same controller/action if you set
* a route like described here.
* http://www.mysite.com/en/admin_folder/login_controller/authenticate_action
* http://www.mysite.com/admin_folder/login_controller/authenticate_action
**/

$route["{$prepended_lang}(.*)"]='$1';

4- Now in your controller if you want to know which language has been requested, do this:

Code:

$lang_code = $this->uri->segment(1);

Some gotchas:
- Verify the length of $lang_code. In the case that it is not 2 characters long, you can assume that $this->uri->segment(1) did not in fact return the language code, but rather the next item after it. This means that the request had no language code : e.g. http://www.mysite.com/somerequest. Make sure to then reset $lang_code to a default language.
- If $lang_code is 2 characters long, check its value against an actual list of supported language codes, in case a user sends you a request such as http://www.mysite.com/fr/somerequest, and you didn't prepare any fr translations. Here too you can use some logic to default any non supported language to a default.


Your application can now be accessed in 2 ways:

http://www.mysite.com/{lang_code}/contro...ar1/value1

and

http://www.mysite.com/controller/action/var1/value1

I'm still testing all this in my own app, please contribute if you find something odd or useful.