function locale_language_from_browser
locale_language_from_browser($languages)
Identify language from the Accept-language HTTP header we got.
We perform browser accept-language parsing only if page cache is disabled, otherwise we would cache a user-specific preference.
Parameters
$languages: An array of language objects for enabled languages ordered by weight.
Return value
A valid language code on success, FALSE otherwise.
Related topics
File
- includes/locale.inc, line 131
- Administration functions for locale.module.
Code
function locale_language_from_browser($languages) { if (empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])) { return FALSE; } // The Accept-Language header contains information about the language // preferences configured in the user's browser / operating system. // RFC 2616 (section 14.4) defines the Accept-Language header as follows: // Accept-Language = "Accept-Language" ":" // 1#( language-range [ ";" "q" "=" qvalue ] ) // language-range = ( ( 1*8ALPHA *( "-" 1*8ALPHA ) ) | "*" ) // Samples: "hu, en-us;q=0.66, en;q=0.33", "hu,en-us;q=0.5" $browser_langcodes = array(); if (preg_match_all('@(?<=[, ]|^)([a-zA-Z-]+|\*)(?:;q=([0-9.]+))?(?:$|\s*,\s*)@', trim($_SERVER['HTTP_ACCEPT_LANGUAGE']), $matches, PREG_SET_ORDER)) { foreach ($matches as $match) { // We can safely use strtolower() here, tags are ASCII. // RFC2616 mandates that the decimal part is no more than three digits, // so we multiply the qvalue by 1000 to avoid floating point comparisons. $langcode = strtolower($match[1]); $qvalue = isset($match[2]) ? (float) $match[2] : 1; $browser_langcodes[$langcode] = (int) ($qvalue * 1000); } } // We should take pristine values from the HTTP headers, but Internet Explorer // from version 7 sends only specific language tags (eg. fr-CA) without the // corresponding generic tag (fr) unless explicitly configured. In that case, // we assume that the lowest value of the specific tags is the value of the // generic language to be as close to the HTTP 1.1 spec as possible. // See http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.4 and // http://blogs.msdn.com/b/ie/archive/2006/10/17/accept-language-header-for-internet-explorer-7.aspx asort($browser_langcodes); foreach ($browser_langcodes as $langcode => $qvalue) { $generic_tag = strtok($langcode, '-'); if (!isset($browser_langcodes[$generic_tag])) { $browser_langcodes[$generic_tag] = $qvalue; } } // Find the enabled language with the greatest qvalue, following the rules // of RFC 2616 (section 14.4). If several languages have the same qvalue, // prefer the one with the greatest weight. $best_match_langcode = FALSE; $max_qvalue = 0; foreach ($languages as $langcode => $language) { // Language tags are case insensitive (RFC2616, sec 3.10). $langcode = strtolower($langcode); // If nothing matches below, the default qvalue is the one of the wildcard // language, if set, or is 0 (which will never match). $qvalue = isset($browser_langcodes['*']) ? $browser_langcodes['*'] : 0; // Find the longest possible prefix of the browser-supplied language // ('the language-range') that matches this site language ('the language tag'). $prefix = $langcode; do { if (isset($browser_langcodes[$prefix])) { $qvalue = $browser_langcodes[$prefix]; break; } } while ($prefix = substr($prefix, 0, strrpos($prefix, '-'))); // Find the best match. if ($qvalue > $max_qvalue) { $best_match_langcode = $language->language; $max_qvalue = $qvalue; } } return $best_match_langcode; }
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https://api.drupal.org/api/drupal/includes!locale.inc/function/locale_language_from_browser/7.x