<form id="signup" method="POST">
                <input type="text" name="firstname" class="form-control" placeholder="First Name *" required/>
                <input type="text" name="lastname" class="form-control" placeholder="Last Name *" required/>
                <input type="text" name="sailno" class="form-control" placeholder="Sail Number *" required/>
                <input type="text" name="boat" class="form-control" placeholder="Boat *" required/>
                <input type="email" name="email" class="form-control" placeholder="Email *" required/>
                <input type="text" name="phone" class="form-control" placeholder="Phone" />
                <input type="hidden" name="cmd" value="_notify-validate" />
                <input type="submit" name="submit" class="submit" />
            </form>

<?php
// Database variables
$servername = "localhost";
$username = "un";
$password = "pw";
$dbname = "dbn";

// PayPal settings
$paypal_email = 'email@email.com';
$return_url = 'http://domain.co.uk/paypal/test.php';
$cancel_url = 'http://domain.co.uk/paypal/payment-cancelled';
$notify_url = 'http:/domain.co.uk/paypal/test.php';

$item_name = 'Item Name';
$item_amount = 1.00;
$invoice = $_POST['invoice'];

// Include Functions
include("functions.php");

// Check if paypal request or response
if (!isset($_POST["txn_id"]) && !isset($_POST["txn_type"])){
    $querystring = '';

    // Firstly Append paypal account to querystring
    $querystring .= "?business=".urlencode($paypal_email)."&";

    // Append amount& currency (£) to quersytring so it cannot be edited in html

    //The item name and amount can be brought in dynamically by querying the $_POST['item_number'] variable.
    $querystring .= "item_name=".urlencode($item_name)."&";
    $querystring .= "amount=".urlencode($item_amount)."&";
    $querystring .= "invoice=".urlencode($invoice)."&";

    //loop for posted values and append to querystring
    foreach($_POST as $key => $value){
        $value = urlencode(stripslashes($value));
        $querystring .= "$key=$value&";
    }

    // Append paypal return addresses
    $querystring .= "return=".urlencode(stripslashes($return_url))."&";
    $querystring .= "cancel_return=".urlencode(stripslashes($cancel_url))."&";
    $querystring .= "notify_url=".urlencode($notify_url);

    // Append querystring with custom field
    //$querystring .= "&custom=".USERID;

    // Redirect to paypal IPN
    header('location:https://www.paypal.com/cgi-bin/webscr'.$querystring);
    exit();
} else {
    //Database Connection
    $link = mysql_connect($servername, $username, $password);
    mysql_select_db($db_name);

    // Response from Paypal

    // read the post from PayPal system and add 'cmd'
    $req = 'cmd=_notify-validate';
    foreach ($_POST as $key => $value) {
        $value = urlencode(stripslashes($value));
        $value = preg_replace('/(.*[^%^0^D])(%0A)(.*)/i','${1}%0D%0A${3}',$value);// IPN fix
        $req .= "&$key=$value";
    }

    // assign posted variables to local variables
    $data['item_name']          = $_POST['item_name'];
    $data['item_number']        = $_POST['item_number'];
    $data['payment_status']     = $_POST['payment_status'];
    $data['payment_amount']     = $_POST['mc_gross'];
    $data['payment_currency']   = $_POST['mc_currency'];
    $data['txn_id']             = $_POST['txn_id'];
    $data['receiver_email']     = $_POST['receiver_email'];
    $data['payer_email']        = $_POST['payer_email'];
    $data['custom']             = $_POST['custom'];

    // post back to PayPal system to validate
    $header = "POST /cgi-bin/webscr HTTP/1.0rn";
    $header .= "Content-Type: application/x-www-form-urlencodedrn";
    $header .= "Content-Length: " . strlen($req) . "rnrn";

    $fp = fsockopen ('ssl://www.paypal.com', 443, $errno, $errstr, 30);

    if (!$fp) {
        // HTTP ERROR

    } else {
        fputs($fp, $header . $req);
        while (!feof($fp)) {
            $res = fgets ($fp, 1024);
            if (strcmp($res, "VERIFIED") == 0) {

                // Used for debugging
                // mail('user@domain.com', 'PAYPAL POST - VERIFIED RESPONSE', print_r($post, true));

                // Validate payment (Check unique txnid & correct price)
                $valid_txnid = check_txnid($data['txn_id']);
                $valid_price = check_price($data['payment_amount'], $data['item_number']);
                // PAYMENT VALIDATED & VERIFIED!
                if ($valid_txnid && $valid_price) {

                    $orderid = updatePayments($data);

                    if ($orderid) {
                        // Payment has been made & successfully inserted into the Database
                        mail("email@email.com","Success","Payment made successfully");
                        echo "updated";
                    } else {
                        // Error inserting into DB
                        // E-mail admin or alert user
                         mail('email@email.com', 'PAYPAL POST - INSERT INTO DB WENT WRONG', print_r($data, true));
                    }
                } else {
                    // Payment made but data has been changed
                    // E-mail admin or alert user
                }

            } else if (strcmp ($res, "INVALID") == 0) {

                // PAYMENT INVALID & INVESTIGATE MANUALY!
                // E-mail admin or alert user

                // Used for debugging
                //@mail("user@domain.com", "PAYPAL DEBUGGING", "Invalid Response<br />data = <pre>".print_r($post, true)."</pre>");
            }
        }
    fclose ($fp);
    }
}
?>

<?php
// STEP 1: read POST data
// Reading POSTed data directly from $_POST causes serialization issues with array data in the POST.
// Instead, read raw POST data from the input stream.
$raw_post_data = file_get_contents('php://input');
$raw_post_array = explode('&', $raw_post_data);
$myPost = array();
foreach ($raw_post_array as $keyval) {
  $keyval = explode ('=', $keyval);
  if (count($keyval) == 2)
    $myPost[$keyval[0]] = urldecode($keyval[1]);
}
// read the IPN message sent from PayPal and prepend 'cmd=_notify-validate'
$req = 'cmd=_notify-validate';
if (function_exists('get_magic_quotes_gpc')) {
  $get_magic_quotes_exists = true;
}
foreach ($myPost as $key => $value) {
  if ($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {
    $value = urlencode(stripslashes($value));
  } else {
    $value = urlencode($value);
  }
  $req .= "&$key=$value";
}

// Step 2: POST IPN data back to PayPal to validate
$ch = curl_init('https://www.paypal.com/cgi-bin/webscr');
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, $req);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
// In wamp-like environments that do not come bundled with root authority certificates,
// please download 'cacert.pem' from "http://curl.haxx.se/docs/caextract.html" and set
// the directory path of the certificate as shown below:
// curl_setopt($ch, CURLOPT_CAINFO, dirname(__FILE__) . '/cacert.pem');
if ( !($res = curl_exec($ch)) ) {
  // error_log("Got " . curl_error($ch) . " when processing IPN data");
  curl_close($ch);
  exit;
}
curl_close($ch);

// inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
  // The IPN is verified, process it
} else if (strcmp ($res, "INVALID") == 0) {
  // IPN invalid, log for manual investigation
}

// inspect IPN validation result and act accordingly
if (strcmp ($res, "VERIFIED") == 0) {
  // The IPN is verified, process it:
  // check whether the payment_status is Completed
  // check that txn_id has not been previously processed
  // check that receiver_email is your Primary PayPal email
  // check that payment_amount/payment_currency are correct
  // process the notification
  // assign posted variables to local variables
  $item_name = $_POST['item_name'];
  $item_number = $_POST['item_number'];
  $payment_status = $_POST['payment_status'];
  $payment_amount = $_POST['mc_gross'];
  $payment_currency = $_POST['mc_currency'];
  $txn_id = $_POST['txn_id'];
  $receiver_email = $_POST['receiver_email'];
  $payer_email = $_POST['payer_email'];
  $invoice = $_POST['invoice'];
  // IPN message values depend upon the type of notification sent.
  // To loop through the &_POST array and print the NV pairs to the screen:

  foreach($_POST as $key => $value) {
    echo $key . " = " . $value . "<br>";

  }
    echo $res;

} else if (strcmp ($res, "INVALID") == 0) {
  // IPN invalid, log for manual investigation
  echo "Error! Paypal stated payment as: <b>" .$res ."<br />";
}
?>