How can I switch languages in CodeIgniter
Configuring Multi-Language Support
First we need to configure the necessary files before we can start using language support. The CodeIgniter config
file, located in the application/config
directory, contains an option called language which defines the default language of the application.
$config['language'] = 'english';
We also need to create the actual files which contain our messages in different languages. These files need to be placed inside the application/language
directory with a separate directory for each language. For example, English
language files should reside in the application/language/english
directory, and French
language files should be located in application/language/french
.
Let’s create some language files that contain error messages for a sample application. Create the file english/message_lang.php
(it’s important that all of the language files have the suffix _lang.php
). The following code contains some sample entries for the content of our language file:
$lang["msg_first_name"] = "First Name";$lang["msg_last_name"] = "Last Name";$lang["msg_dob"] = "Date of Birth";$lang["msg_address"] = "Address";
Of course, you can have multiple language files inside a single language directory. It’s recommended to group your messages into different files based on their context and purpose, and prefix your message keys with a file-specific keyword for consistency.
Another way is to create separate message files for each controller. The advantage of this technique is that only the required messages are loaded instead of an entire language file which can create a certain level of performance overhead.
Loading the Language Files inside Controller
Even though we create language files, they are not effective until we load them inside controllers. The following code shows how we can load the files inside a controller:
class TestLanguage extends CI_Controller{ public function __construct() { parent::__construct(); $this->lang->load("message","english"); } function index() { $data["language_msg"] = $this->lang->line("msg_hello_english"); $this->load->view('language_view', $data); }}
We usually work with the language files within the controllers and views (using language files inside models is not such a good thing). Here we’ve used a controller’s constructor to load the language file so it can be used throughout the whole class, then we reference it in the class’ index()
method.
The first parameter to the lang->load()
method will be the language’s filename without the _lang
suffix. The second paramter, which is optional, is the language directory. It will point to default language in your config
if it’s not provided here.
We can directly reference the entries of a language file using the lang->line()
method and assign it’s return to the data passed into the view templates. Inside the view, we can then use the above language message as $language_msg
.
There may be an occasion when we need to load language files directly from the views as well. For example, using language items for form labels might be considered a good reason for directly loading and accessing messages inside views. It’s possible to use the same access method for these files inside views as inside controllers.
$this->lang->line("msg_hello_english");
Though it works perfectly, it could be confusing to have $this
when our view template code isn’t an actual class. We can also use the following code with the support of the language helper to load language entries inside views, which gives us cleaner code.
lang("msg_view_english");
That’s basically all you need to know to get started working with CodeIgniter language files. But even though this is simple enough, it’s unnecessary and duplicated effort to load the necessary language files in each of the controllers, especially if your project contains hundreds of classes. Luckily, we can use CodeIgniter hooks to build a quick and effective solution for loading language files automatically for each controller.
Assigning Language Loading Responsibilities to Hooks
CodeIgniter calls a few built-in hooks as part of its execution process. You can find a complete list of hooks in the user guide. We’ll use the post_controller_constructor hook which is called immediately after our controller is instantiated and prior to any other method calls.
We enable hooks in our application by setting the enable_hooks
parameter in the main config
file.
$config['enable_hooks'] = TRUE;
Then we can open the hooks.php
file inside the config
directory and create a custom hook
as shown in the following code:
$hook['post_controller_constructor'] = array( 'class' => 'LanguageLoader', 'function' => 'initialize', 'filename' => 'LanguageLoader.php', 'filepath' => 'hooks');
This defines the hook and provides the necessary information to execute it. The actual implementation will be created in a custom class inside the application/hooks
directory.
class LanguageLoader{ function initialize() { $ci =& get_instance(); $ci->load->helper('language'); $ci->lang->load('message','english'); }}
In here we don’t have the access to the language library using $this->lang
, so we need to get the CI
object instance using the get_instance()
function, and then we load the language as we did earlier. Now the language file will be available for every controller of our application without the need to manually load it inside the controllers.
Switching Between Different Languages
Once we have established support for multiple languages, a link for each language can be provided to the user, generally in one of our application’s menus, which the users can click and switch the language. A session
or cookie
value can be used to keep track of the active language.
Let’s see how we can manage language switching using the hooks
class we generated earlier. First we need to create a class to switch the language; we’ll be using a separate controller for this as shown below:
class LangSwitch extends CI_Controller{ public function __construct() { parent::__construct(); $this->load->helper('url'); } function switchLanguage($language = "") { $language = ($language != "") ? $language : "english"; $this->session->set_userdata('site_lang', $language); redirect(base_url()); }}
Then we need to define links to switch each of the available languages.
<a href='<?php echo $base_url; ?>langswitch/switchLanguage/english'>English</a><a href='<?php echo $base_url; ?>langswitch/switchLanguage/french'>French</a>
Whenever the user chooses a specific language, the switchLanguage()
method of the LangSwitch
class will assign the selected languages to the session
and redirect the user to the home page.
Now the active language will be changed in the session, but still it won’t get affected until we load the specific language file for the active language. We also need to modify our hooks class to load the language dynamically from the session
.
class LanguageLoader{ function initialize() { $ci =& get_instance(); $ci->load->helper('language'); $site_lang = $ci->session->userdata('site_lang'); if ($site_lang) { $ci->lang->load('message',$ci->session->userdata('site_lang')); } else { $ci->lang->load('message','english'); } }}
Inside the LanguageLoader
class we get the active language and load the necessary language files, or we load the default language if the session key is absent. We can load multiple language files of a single language inside this class.
Read more from here Multi-Language Support in CodeIgniter
Would have to have more info on your multi-language setup, but SitePoint wrote a nice tutorial on how to do exactly what you are asking, but again it really depends on how you set up your languages.
http://www.sitepoint.com/multi-language-support-in-codeigniter/
If that doesn't help, it kinda looks like you have separated your index.php into language directories? If that is the case, you could set up a route so when you click the English flag it sets a session variable to use English site, and returns you to current page.
HTML:
<form method="POST" action="/change-lang"> <input type="hidden" name="uri" value="<?= uri_string(); ?>" /> <input type="image" src="/images/en-flag.jpg" name="lang" value="en" /> <input type="image" src="/images/it-flag.jpg" name="lang" value="it /></form>
Controller:
<?php// Other methods and __construct() here....public function change-lang() { $uri = $this->input->post('uri'); $lang = $this->input->post('lang'); $_SESSION['lang'] = $lang; redirect($uri, 'refresh');}
config/config.php
...
if(isset($_SESSION['lang'])) { $config['base_url'] = 'http://localhost/projectname/'.$_SESSION['lang'].'/';} else { $config['base_url'] = 'http://localhost/projectname/en/';}
...