Validate facebook profile URL

Something like this:

function fbUser( $url ) {
    preg_match('~^https?://(www.)?facebook.com/(profile\.php\?id=)?(.*)~',$url,$matches);
    return $matches[3];
}

See working at IDEONE .

Understanding RegEx:

~^https?://(www.)?facebook.com/(profile\.php\?id=)?(.*)~   Essa é a RegEx completa.
~                                                      ~   Delimitadores de começo e fim
 ^                                                         Indica o começo da linha
      s?   (www.)?             (profile\.php\?id=)?        Campos opcionais
  http  ://       facebook.com/                            Caracteres fixos (obrigatórios)
                                                   (.*)    retornamos este valor

Here is an even more robust version, which separates parameters from query string and ignores ? and / in named URLs:

function fbUser( $url ) {
   $rgx='~^https?://(www\.)?facebook.com/(?|profile\.php\?(?:.*&)*id=([^&]*)|([^/\?]*))~';
   if( preg_match( $rgx, $url, $matches ) ) return $matches[2];
}

See working at IDEONE .

This solution used our RegEx master's suggestion, @GuilhermeLautert , to use branch reset (alternative groups), with the syntax (? |)     

Basically using parse_url () and parse_str () to do it with ease.

Return ID or null if it is not the facebook url or can not detect the id.

function getFbId($url){
    $fbId = null;
    $info = parse_url($url);

    if( isset($info['host']) && preg_match('/facebook\.com/', $info['host']) ){
        if(isset($info['query'])){
            $qs = parse_str($info['query'], $params);
            if( isset($params['id']) ){
                //pega o id aqui $params['id']
                $fbId = $params['id'];
            }
        }else if( isset($info['path']) ){
            $path = str_replace('/', '', $info['path']);
            //precisa ajustar essa expressao, não lembro exatamente se isso tudo é permitido ou falta algo
            if(preg_match('/\.php/', $path)==0){
                if( preg_match('/([a-zA-Z0-9]|\.|_)+/', $path)>0 ){
                    $fbId = $path;
                }
            }
        }
    }
    return $fbId;
}

var_dump(getFbId('http://www.facebook.com/walterwhite'));
var_dump(getFbId('http://www.facebook.com/profile.php?id=xxxxx'));

I confess that it is not the most beautiful function in the world but solves it.

Returning the user id has a certain difficulty, if it is the public name, the form above will solve you if you have the url input. If you need the actual user ID I suggest using the gift and manipulating the profile image class: "profilePicThumb" and picking the string between "fbid=" and "& set". This is the id used by facebook, for Ads campaign purposes will not turn out anything, since the face has excluded the option to upload bases based on Id. I hope I have helped.

There goes everything in a single REGEX, I finished now:

//Retirar possíveis espaços na digitação
    $odominioface = preg_replace('/([\s]+)/i', '', $_POST['link_do_facebook_profile']);
    preg_match('/^(http(?:s)?[\:][\/][\/](?:www[\.])?facebook[\.]com[\/])(?:([a-z0-9\-\_]+)|(?:profile[\.]php[\?]id[\=]([0-9]{15})))$/i', $odominioface, $resultadodominioface);

if((isset($resultadodominioface[1]) == true) and ($resultadodominioface[1] != null)){

if((isset($resultadodominioface[2]) == true) and ($resultadodominioface[2] != null)){

echo "Puts grilla bicho eu achei o nome do perfil na URL! O nome é: ".$resultadodominioface[2]."<br />";

} elseif((isset($resultadodominioface[3]) == true) and ($resultadodominioface[3] != null)){

echo "Não encontrei o nome do perfil, mas pelo menos achei o id! O id é: ".$resultadodominioface[3]."<br />";

} else{
echo "Que mer* bicho! Não encontrei nada!<br />";
}

}

THE VARIABLES:

$resultadodominioface[1] -> Returns the name of the domain, if not nouver that everything else is already disregarded in the script

$resultadodominioface[2] -> The name of the guy in the URL, is not mandatory because the script does not matter because it analyzes the existence of it or not.

$resultadodominioface[3] -> The id of the face

In case I evaluated the variable ($ resultadodominioface [1]), because if there is no valid domain, the rest will be invalid, because everything depends on it. In this case the regular expression allows:

link OR link

link OR link

link OR link

link OR link

I've done it now and tested a lot! Thank you! I do not need the script but if I need to, thanks to you, it's ready! Thanks!