Language Switcher App

A PHP language switcher with templates
Dave Smith, Trinity College Dublin Web Design Office, 2012

Example

The example page is set up to detect English, Gaeilge and Russian and switch between them.

Add the switcher

1. Add this HTML to every page where the language switcher needs to be displayed

2. Add this code to the top of every page the language switcher will be on, or at least before the switcher HTML

3. Style it, the following is a starting point for template 4

Add more languages to the switcher

Look for $i18n in /www.tcd.ie/uns/language-switcher/2/app.php and add the new language to the array. Make sure the new language has an entry for language, home and ianasubtag_language_name.

For example adding Russian would go from:

$i18n = array (
    'ianasubtag_language_name' => array (
        'en' => 'English',
        'ga' => 'Gaeilge',
    ),
    'home' => array (
        'en' => 'Home',
        'ga' => 'Baile',
    ),
    'language' => array (
        'en' => 'Language',
        'ga' => 'Teagmháil',
    ),
);

to:

$i18n = array (
    'ianasubtag_language_name' => array (
        'en' => 'English',
        'ga' => 'Gaeilge',
        'ru' => 'Ruski',
    ),
    'home' => array (
        'en' => 'Home',
        'ga' => 'Baile',
        'ru' => 'Homeski',
    ),
    'language' => array (
        'en' => 'Language',
        'ga' => 'Teagmháil',
        'ru' => 'Langski',
    ),
);

App Options

languageSwitcher2AppTCD(array(
	'siteRoot' => string,
	'ianaSubtags' => array (string, string, ...),
	'homeImageURL' => string,
	'template' => number,
));

• siteRoot, required
  URL of the site
  • Must end without a slash
• ianaSubtags, required
  Array of iana subtags that the app will attempt to detect
  • The first item determines the default language, for example with array ('en', 'ga', 'ru') English is the default language
  • If array ('en', 'ga') is given then the app will only look for English and Gaeilge pages, for example index.php, bob.php, index.ru.php would be detected as English, and index.ga.php, bob.ga.php will be detected as Gaeilge
• homeImageURL
  URL of an image to use instead of (Home) text which appears with certain templates when there isn't a directly equivalent page to switch to
• template
  Template to use
  • There are a number of templates defined in the app and more can be added. The default template is 4

App Output

array(
	'html' => string,
	'lang' => string,
	'subtag' => string,
}

• html
  The HTML outputted from the switcher template
• lang
  The ianasubtag of the page, useful for lang attributes
• subtag
  An empty string for the default language or the ianasubtag of the page
• ext
  A empty string for the default language or '.subtag'. Useful when including files, e.g.,<?php if(!@include $_SERVER['DOCUMENT_ROOT'].'/tms/m/h'.$languageSwitcherTCD['ext'].'.php') include $_SERVER['DOCUMENT_ROOT'].'/tms/m/h.php'; ?>, which attempts to include the current language include file, which may be the default language, and if the current language include file does not exist the default language include file is included
• i18n
  An array of the internationalisation text strings relating to the language switcher, for example getting the word Language in different languages: $languageSwitcherTCD['i18n']['language'][$languageSwitcherTCD['lang']]
• defaultLang
  The ianasubtag of the default language

How the app detects the language

First tell the app what languages to search for, for example 'ianaSubtags' => array ('en', 'ga',), which tells the app the default language is English and to detect Gaeilge. See IANA Subtag Registry for a complete list or subtags and their corresponding language.

Then the app checks the filename of the loaded page and determines the language, for example index.php or bob.php would be detected as English (default language) and index.ga.php and bob.ga.php would be detected as Gaeilge.