/**
* Extracts a keyword from a raw not encoded URL.
* Will only extract keyword if a known search engine has been detected.
* Returns the keyword:
* - in UTF8: automatically converted from other charsets when applicable
* - strtolowered: "QUErY test!" will return "query test!"
* - trimmed: extra spaces before and after are removed
*
* The function returns false when a keyword couldn't be found.
* eg. if the url is "http://www.google.com/partners.html" this will return false,
* as the google keyword parameter couldn't be found.
*
* @see unit tests in /tests/core/Common.test.php
* @param string $referrerUrl URL referrer URL, eg. $_SERVER['HTTP_REFERER']
* @return array|bool false if a keyword couldn't be extracted,
* or array(
* 'name' => 'Google',
* 'keywords' => 'my searched keywords')
*/
public function extractInformationFromUrl($referrerUrl)
{
$referrerParsed = @parse_url($referrerUrl);
$referrerHost = '';
if (isset($referrerParsed['host'])) {
$referrerHost = $referrerParsed['host'];
}
if (empty($referrerHost)) {
return false;
}
// some search engines (eg. Bing Images) use the same domain
// as an existing search engine (eg. Bing), we must also use the url path
$referrerPath = '';
if (isset($referrerParsed['path'])) {
$referrerPath = $referrerParsed['path'];
}
$query = '';
if (isset($referrerParsed['query'])) {
$query = $referrerParsed['query'];
}
// Google Referrers URLs sometimes have the fragment which contains the keyword
if (!empty($referrerParsed['fragment'])) {
$query .= '&' . $referrerParsed['fragment'];
}
$referrerHost = $this->getEngineHostFromUrl($referrerHost, $referrerPath, $query);
if (empty($referrerHost)) {
return false;
}
$definitions = $this->getDefinitionByHost($referrerHost);
$searchEngineName = $definitions['name'];
$variableNames = $definitions['params'];
$key = null;
if ($searchEngineName === 'Google Images' || $searchEngineName === 'Google' && strpos($referrerUrl, '/imgres') !== false) {
if (strpos($query, '&prev') !== false) {
$query = urldecode(trim(UrlHelper::getParameterFromQueryString($query, 'prev')));
$query = str_replace('&', '&', strstr($query, '?'));
}
$searchEngineName = 'Google Images';
} elseif ($searchEngineName === 'Google' && (strpos($query, '&as_') !== false || strpos($query, 'as_') === 0)) {
$keys = array();
$key = UrlHelper::getParameterFromQueryString($query, 'as_q');
if (!empty($key)) {
array_push($keys, $key);
}
$key = UrlHelper::getParameterFromQueryString($query, 'as_oq');
if (!empty($key)) {
array_push($keys, str_replace('+', ' OR ', $key));
}
$key = UrlHelper::getParameterFromQueryString($query, 'as_epq');
if (!empty($key)) {
array_push($keys, "\"{$key}\"");
}
$key = UrlHelper::getParameterFromQueryString($query, 'as_eq');
if (!empty($key)) {
array_push($keys, "-{$key}");
}
$key = trim(urldecode(implode(' ', $keys)));
}
if ($searchEngineName === 'Google') {
// top bar menu
$tbm = UrlHelper::getParameterFromQueryString($query, 'tbm');
switch ($tbm) {
case 'isch':
$searchEngineName = 'Google Images';
break;
case 'vid':
$searchEngineName = 'Google Video';
break;
case 'shop':
$searchEngineName = 'Google Shopping';
break;
}
}
if (empty($key)) {
foreach ($variableNames as $variableName) {
if ($variableName[0] == '/') {
// regular expression match
if (preg_match($variableName, $referrerUrl, $matches)) {
$key = trim(urldecode($matches[1]));
break;
}
} else {
// search for keywords now &vname=keyword
$key = UrlHelper::getParameterFromQueryString($query, $variableName);
$key = trim(urldecode($key));
// Special cases: empty or no keywords
if (empty($key) && ($searchEngineName == 'Google' && (empty($query) && (empty($referrerPath) || $referrerPath == '/') && empty($referrerParsed['fragment'])) || $searchEngineName == 'Yahoo!' && $referrerParsed['host'] == 'r.search.yahoo.com' || strpos($query, sprintf('&%s=', $variableName)) !== false || strpos($query, sprintf('?%s=', $variableName)) !== false || $searchEngineName == 'Ixquick' || $searchEngineName == 'Google Images' || $searchEngineName == 'DuckDuckGo')) {
$key = false;
}
if (!empty($key) || $key === false) {
break;
}
}
}
}
// $key === false is the special case "No keyword provided" which is a Search engine match
if ($key === null || $key === '') {
return false;
}
if (!empty($key)) {
if (!empty($definitions['charsets'])) {
$key = $this->convertCharset($key, $definitions['charsets']);
}
$key = Common::mb_strtolower($key);
}
return array('name' => $searchEngineName, 'keywords' => $key);
}
