Question

I need a form to autolink links that users input in text fields. I found an example on stack which works perfectly, except for one thing. if the user inputs a link without including http:// or https:// and instead starts the link only using www. the link does not work properly.

ie a user input would be

check out our twitter!
www.twitter.com/#!/profile

and our facebook!
https://www.facebook.com/profile

the output would be

check out our twitter!
<a href="www.twitter.com/#!/profile">www.twitter.com/#!/profile</a>

and our facebook!
<a href="https://www.facebook.com/profile">http://www.facebook.com/profile</a>

so the facebook link works perfectly, but the twitter one would not, as its being linked to the current location the user is on plus the new link, ie if they are currently on www.example.com the link would become www.example.com/www.twitter.com/#!/profile

for the life of me, i cant figure out how to fix this by simply adding http:// to the beginning of the link, this is the function:

function auto_link_text($text) {
    $pattern  = '#\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))#';
    return preg_replace_callback($pattern, 'auto_link_text_callback', $text);
}

function auto_link_text_callback($matches) {
     $max_url_length = 50;
    $max_depth_if_over_length = 2;
    $ellipsis = '&hellip;';

    $url_full = $matches[0];
    $url_short = '';

    if (strlen($url_full) > $max_url_length) {
        $parts = parse_url($url_full);
        $url_short = $parts['scheme'] . '://' . preg_replace('/^www\./', '',  $parts['host']) . '/';

    $path_components = explode('/', trim($parts['path'], '/'));
    foreach ($path_components as $dir) {
        $url_string_components[] = $dir . '/';
    }

    if (!empty($parts['query'])) {
        $url_string_components[] = '?' . $parts['query'];
    }

    if (!empty($parts['fragment'])) {
        $url_string_components[] = '#' . $parts['fragment'];
    }

    for ($k = 0; $k < count($url_string_components); $k++) {
        $curr_component = $url_string_components[$k];
        if ($k >= $max_depth_if_over_length || strlen($url_short) + strlen($curr_component) > $max_url_length) {
            if ($k == 0 && strlen($url_short) < $max_url_length) {
                // Always show a portion of first directory
                $url_short .= substr($curr_component, 0, $max_url_length - strlen($url_short));
            }
            $url_short .= $ellipsis;
            break;
        }
        $url_short .= $curr_component;
    }

} else {
    $url_short = $url_full;
}

    return "<a rel=\"nofollow\" href=\"$url_full\">$url_short</a>";
}

Answer 1

Use strpos function.
if the input contains “http://” forward directly. Otherwise add it direct it.