What are some common pitfalls when using PHP to extract keywords from a search engine referrer?

One common pitfall when extracting keywords from a search engine referrer in PHP is not properly handling different search engines' referral URLs. Each search engine may have a different format for passing keywords, so it's important to account for these variations. One way to solve this issue is to create a function that parses the referral URL based on the search engine and extracts the keywords accordingly. 

function extractKeywordsFromReferrer($referrer) {
    $keywords = '';
    
    if (strpos($referrer, 'google') !== false) {
        if (preg_match('/q=([^&]*)/', $referrer, $matches)) {
            $keywords = urldecode($matches[1]);
        }
    } elseif (strpos($referrer, 'bing') !== false) {
        if (preg_match('/q=([^&]*)/', $referrer, $matches)) {
            $keywords = urldecode($matches[1]);
        }
    } elseif (strpos($referrer, 'yahoo') !== false) {
        if (preg_match('/p=([^&]*)/', $referrer, $matches)) {
            $keywords = urldecode($matches[1]);
        }
    }
    
    return $keywords;
}

$referrer = $_SERVER['HTTP_REFERER'];
$keywords = extractKeywordsFromReferrer($referrer);

echo "Keywords from referrer: " . $keywords;

Keywords

PHP search engine referrer keyword extraction regular expressions error handling

Related Questions