Implementation of "url" rule validation on Laravel

The functions used can be found from searching the vendor folder on your codebase.

The validateUrl function is as follows :

public function validateUrl($attribute, $value)
{
    if (! is_string($value)) {
        return false;
    }

    /*
     * This pattern is derived from Symfony\Component\Validator\Constraints\UrlValidator (2.7.4).
     *
     * (c) Fabien Potencier <[email protected]> http://symfony.com
     */
    $pattern = '~^
        ((aaa|aaas|about|acap|acct|acr|adiumxtra|afp|afs|aim|apt|attachment|aw|barion|beshare|bitcoin|blob|bolo|callto|cap|chrome|chrome-extension|cid|coap|coaps|com-eventbrite-attendee|content|crid|cvs|data|dav|dict|dlna-playcontainer|dlna-playsingle|dns|dntp|dtn|dvb|ed2k|example|facetime|fax|feed|feedready|file|filesystem|finger|fish|ftp|geo|gg|git|gizmoproject|go|gopher|gtalk|h323|ham|hcp|http|https|iax|icap|icon|im|imap|info|iotdisco|ipn|ipp|ipps|irc|irc6|ircs|iris|iris.beep|iris.lwz|iris.xpc|iris.xpcs|itms|jabber|jar|jms|keyparc|lastfm|ldap|ldaps|magnet|mailserver|mailto|maps|market|message|mid|mms|modem|ms-help|ms-settings|ms-settings-airplanemode|ms-settings-bluetooth|ms-settings-camera|ms-settings-cellular|ms-settings-cloudstorage|ms-settings-emailandaccounts|ms-settings-language|ms-settings-location|ms-settings-lock|ms-settings-nfctransactions|ms-settings-notifications|ms-settings-power|ms-settings-privacy|ms-settings-proximity|ms-settings-screenrotation|ms-settings-wifi|ms-settings-workplace|msnim|msrp|msrps|mtqp|mumble|mupdate|mvn|news|nfs|ni|nih|nntp|notes|oid|opaquelocktoken|pack|palm|paparazzi|pkcs11|platform|pop|pres|prospero|proxy|psyc|query|redis|rediss|reload|res|resource|rmi|rsync|rtmfp|rtmp|rtsp|rtsps|rtspu|secondlife|s3|service|session|sftp|sgn|shttp|sieve|sip|sips|skype|smb|sms|smtp|snews|snmp|soap.beep|soap.beeps|soldat|spotify|ssh|steam|stun|stuns|submit|svn|tag|teamspeak|tel|teliaeid|telnet|tftp|things|thismessage|tip|tn3270|turn|turns|tv|udp|unreal|urn|ut2004|vemmi|ventrilo|videotex|view-source|wais|webcal|ws|wss|wtai|wyciwyg|xcon|xcon-userid|xfire|xmlrpc\.beep|xmlrpc.beeps|xmpp|xri|ymsgr|z39\.50|z39\.50r|z39\.50s))://                                 # protocol
        (([\pL\pN-]+:)?([\pL\pN-]+)@)?          # basic auth
        (
            ([\pL\pN\pS\-\.])+(\.?([\pL]|xn\-\-[\pL\pN-]+)+\.?) # a domain name
                |                                              # or
            \d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}                 # an IP address
                |                                              # or
            \[
                (?:(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){6})(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:::(?:(?:(?:[0-9a-f]{1,4})):){5})(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:[0-9a-f]{1,4})))?::(?:(?:(?:[0-9a-f]{1,4})):){4})(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,1}(?:(?:[0-9a-f]{1,4})))?::(?:(?:(?:[0-9a-f]{1,4})):){3})(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,2}(?:(?:[0-9a-f]{1,4})))?::(?:(?:(?:[0-9a-f]{1,4})):){2})(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,3}(?:(?:[0-9a-f]{1,4})))?::(?:(?:[0-9a-f]{1,4})):)(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,4}(?:(?:[0-9a-f]{1,4})))?::)(?:(?:(?:(?:(?:[0-9a-f]{1,4})):(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9]))\.){3}(?:(?:25[0-5]|(?:[1-9]|1[0-9]|2[0-4])?[0-9])))))))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,5}(?:(?:[0-9a-f]{1,4})))?::)(?:(?:[0-9a-f]{1,4})))|(?:(?:(?:(?:(?:(?:[0-9a-f]{1,4})):){0,6}(?:(?:[0-9a-f]{1,4})))?::))))
            \]  # an IPv6 address
        )
        (:[0-9]+)?                              # a port (optional)
        (/?|/\S+|\?\S*|\#\S*)                   # a /, nothing, a / with something, a query or a fragment
    $~ixu';

    return preg_match($pattern, $value) > 0;
}

This can be found at vendor/laravel/framework/src/Illuminate/Validation/Concerns/ValidatesAttributes.

You can also find this at the Laravel API docs here which will provide a link to the GitHub if you click the line number at the end.