Detect browser language in PHP and set $ locale accordingly

Question

I am trying to ensure that when someone visits my Wordpress page, the .po (language-) packages of his pefered language are loaded. At the moment, you can change the language by adding the parameter? Lang = in URL. But I want the correct language to be selected based on the language of the browser.

My code is:

<?php // start the session session_start(); $browserlang = " ".$_SERVER['HTTP_ACCEPT_LANGUAGE']; // if there a "lang" parameter in the URL... if( isset( $_GET[ 'lang' ] ) ) { // ...set a session variable named WPLANG based on the URL parameter... $_SESSION[ 'WPLANG' ] = $_GET[ 'lang' ]; // ...and define the WPLANG constant with the WPLANG session variable $locale = $_SESSION[ 'WPLANG' ]; echo 'Based on URL parameter'; // if there isn't a "lang" parameter in the URL... } else { // if the WPLANG session variable is already set... if( isset( $_SESSION[ 'WPLANG' ] ) ) { // ...define the WPLANG constant with the WPLANG session variable $locale = $_SESSION[ 'WPLANG' ]; echo 'Based on session variable'; // if the WPLANG session variable isn't set... } else { // set the WPLANG constant to your default language code is (or empty, if you don't need it) $locale = $browserlang; echo 'Should be based on browser language. It is:' . $browserlang; } }; ?> 

$ locale is used to set the language and select the correct .po files.

Now I want $ locale to be

$ locale = 'en_US'

by default, but when someone enters the page with the default "de", "de_DE", "de_CH" or "de_AT", it should be.

$ locale = 'de_DE'

The currently used im code does not work.

 $browserlang = " ".$_SERVER['HTTP_ACCEPT_LANGUAGE']; echo $browserlang; 

Shows me the correct language, which is "de_DE", but $locale = $browserlang does nothing. On the other hand, when I set $locale = 'de_DE' , it works ...

Thanks guys in advance.

Edit:

When I use echo $locale , de-DE says. This is very strange because it does not work ...

Edit 2:

This is because it should be de_DE (underscore) not de-DE (minus) ... how to fix it?

Edit 3:

Finally, it works.

Answer 1

Edit 3:

It worked:

 <?php // start the session session_start(); // if there a "lang" parameter in the URL... if( isset( $_GET[ 'lang' ] ) ) { // ...set a session variable named WPLANG based on the URL parameter... $_SESSION[ 'WPLANG' ] = $_GET[ 'lang' ]; // ...and define the WPLANG constant with the WPLANG session variable $locale = $_SESSION[ 'WPLANG' ]; $languagemsg = 'based on url parameter'; // if there isn't a "lang" parameter in the URL... } else { // if the WPLANG session variable is already set... if( isset( $_SESSION[ 'WPLANG' ] ) ) { // ...define the WPLANG constant with the WPLANG session variable $locale = $_SESSION[ 'WPLANG' ]; $languagemsg = 'based on session variable'; // if the WPLANG session variable isn't set... } else { // set the WPLANG constant to your default language code is (or empty, if you don't need it) $browserlang = substr($_SERVER["HTTP_ACCEPT_LANGUAGE"],0,2); if ($browserlang == 'de') {$browserlang = 'de_DE';} else {$browserlang = 'en_US';} $_SESSION[ 'WPLANG' ] = $browserlang; $locale = $browserlang; $languagemsg = 'based on browser language'; } }; ?> 

Modern browsers always list the preferred language over others. That's why I choose only the first two letters of the bite:

 $browserlang = substr($_SERVER["HTTP_ACCEPT_LANGUAGE"],0,2); 

I now set $browserlang = de_DE for all language codes starting with "de". For all other languages, I set $browserlang = en_US .

'$ languagemsg' is for explanation only.

Answer 2

Shows me the correct language, which is "de_DE",

It does not follow. The code you showed us inserts a space before the header value.

In addition, your code does not handle the header of the multi-valued language accept-language , which may also include settings (for example, see here for the parser)

How you normalize the value ({"de", "de_DE", "de_CH", "de_AT"} → "de_DE") is up to you.