<?php
class linkedInLogin {
    public function login(){
        $username = 'Email Here';
        $password = 'Password here';
        $csrf = $this->fetchCSRF();
        if($csrf == false){
            echo 'Error: loginCsrfParam fetching failed.';
            return;
        }
        //login form action url
        $url="https://www.linkedin.com/uas/login-submit";
        //$postinfo = "session_key=".$username."&session_password=".$password."&loginCsrfParam=".$csrf;
        $postfields = array('session_key' => $username, 'session_password' => $password, 'loginCsrfParam' => $csrf);
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_HEADER, false);
        curl_setopt($ch, CURLOPT_NOBODY, false);
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
        curl_setopt($ch, CURLOPT_COOKIESESSION, true);
        curl_setopt($ch, CURLOPT_COOKIEJAR, 'cookie.txt');
        curl_setopt($ch, CURLOPT_USERAGENT,
            "Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.7.12) Gecko/20050915 Firefox/1.0.7");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); //@TODO change back: curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_REFERER, 'https://www.linkedin.com/uas/login');
        curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 0);
        curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $postfields);
        echo curl_exec($ch);
        curl_close($ch);
    }

    // Fetches the CSRF for login authentication
    private function fetchCSRF(){
        $url = 'https://linkedin.com/uas/login';
        $html = file_get_contents($url);
        $precsrf = (int) strpos($html, '<input type="hidden" name="loginCsrfParam" value="');
        $postcsrf = (int) strpos($html, '" id="loginCsrfParam-login">');
        $length = $postcsrf - $precsrf - 50; // The -50 / + 50 is to correct for: <input type="hidden" name="login...
        $csrf = substr($html, $precsrf + 50, $length);
        if($csrf == false){
            return false;
        }
        return $csrf;
    }
}