<?php
$data = array("grant_type" => "password", "client_id" => "*********************************","client_secret"=>"************","username" =>"*********","password" => "**************");
$data_string = json_encode($data);
$url='https://login.salesforce.com/services/oauth2/token';
$ch = curl_init('https://login.salesforce.com/services/oauth2/token');

curl_setopt($ch,CURLOPT_SSL_VERIFYPEER,false);
curl_setopt($ch, CURLOPT_CUSTOMREQUEST, "POST");
curl_setopt($ch, CURLOPT_POSTFIELDS, $params);
curl_setopt($ch, CURLOPT_HEADER,true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, false);
curl_setopt($ch,CURLOPT_VERBOSE,true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array(
    'Content-Type: application/json',
    'Content-Length: ' . strlen($data_string))
);

$result = curl_exec($ch);

if($result === false)
{
    echo 'Curl error: ' . curl_error($ch);
}
else
{
    echo 'Operation completed without any errors';
}


$info = curl_getinfo($ch);
echo curl_getinfo($ch);
echo $info['access_token'];
echo curl_getinfo($ch, CURLINFO_HTTP_CODE);
curl_close($ch);

$result1= file_get_contents($url);
var_dump(json_decode($result1, true));
}

?>

<?php
require_once 'configPWFlow.php';

session_start();

$token_url = LOGIN_URI . "/services/oauth2/token";


$params = "grant_type=password"
    . "&client_id=" . CLIENT_ID
    . "&client_secret=" . CLIENT_SECRET
    . "&username=" . USERNAME
    . "&password=" . PASSWORD;

$curl = curl_init($token_url);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $params);

$json_response = curl_exec($curl);
...
?>