尝试使用curl访问facebook访问令牌并获取错误“缺少授权码”

Question

我试图通过curl获取Facebook访问令牌我有这个错误 “缺少授权码” 这是我的代码

$curl = "https://graph.facebook.com/oauth/access_token?client_id=xxxxx&redirect_uri=myurl/fb-tokens/&client_secret=xxxx&code=".$_GET['code']."";
        $crl = curl_init();
        $timeout = 5;
        curl_setopt ($crl, CURLOPT_URL,$curl);
        curl_setopt ($crl, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt ($crl, CURLOPT_CONNECTTIMEOUT, $timeout);
        $ret = curl_exec($crl);
        curl_close($crl);
        $final_result = json_decode($ret);
        print_r($final_result); 

任何人都可以帮助我吗？