php - get POST data sent from PayPal to IPN Listener -

i trying pass custom value paypal , have paypal return php ipn listener. code using. original code published on github. made small modification: added fuction getpostdata() post data sent paypal, getpostdata() returns empty string. how can access post data paypal sends me?

this how anchor element looks:

<a id="submit-button" href="https://www.paypal.com/cgi-bin/webscr?cmd=_s-xclick&hosted_button_id=someid&custom=customdata">pay paypal</a> 

other code:

    <?php     class paypalipn     {     private $use_sandbox = false;     private $postdata = "";      private $use_local_certs = true;      /*      * paypal ipn postback endpoints      */      const verify_uri = 'https://ipnpb.paypal.com/cgi-bin/webscr';     const sandbox_verify_uri = 'https://ipnpb.sandbox.paypal.com/cgi-bin/webscr';      /*      * possible responses paypal after request issued.      */      const valid = 'verified';     const invalid = 'invalid';       /**      * sets ipn verification sandbox mode (for use when testing,      * should not enabled in production).      * @return void      */     public function usesandbox()     {         $this->use_sandbox = true;     }       /**      * determine endpoint post verification data to.      * @return string      */     public function getpaypaluri()     {         if ($this->use_sandbox) {             return self::sandbox_verify_uri;         } else {             return self::verify_uri;         }     }       /**      * verification function      * sends incoming post data paypal using curl library.      *      * @return bool      * @throws exception      */        public function verifyipn()     {         if ( ! count($_post)) {             throw new exception("missing post data");         }          $raw_post_data = file_get_contents('php://input');         $raw_post_array = explode('&', $raw_post_data);         $mypost = [];         foreach ($raw_post_array $keyval) {             $keyval = explode('=', $keyval);             if (count($keyval) == 2) {                 // since not want plus in datetime string encoded space, manually encode it.                 if ($keyval[0] === 'payment_date') {                     if (substr_count($keyval[1], '+') === 1) {                         $keyval[1] = str_replace('+', '%2b', $keyval[1]);                     }                 }                 $mypost[$keyval[0]] = urldecode($keyval[1]);             }         }          $postdata = $raw_post_data;          // build body of verification post request, adding _notify-validate command.         $req = 'cmd=_notify-validate';         $get_magic_quotes_exists = false;         if (function_exists('get_magic_quotes_gpc')) {             $get_magic_quotes_exists = true;         }         foreach ($mypost $key => $value) {             if ($get_magic_quotes_exists == true && get_magic_quotes_gpc() == 1) {                 $value = urlencode(stripslashes($value));             } else {                 $value = urlencode($value);             }             $req .= "&$key=$value";         }          // post data paypal, using curl. throw exceptions if errors occur.         $ch = curl_init($this->getpaypaluri());         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_sslversion, 6);         curl_setopt($ch, curlopt_ssl_verifypeer, 1);         curl_setopt($ch, curlopt_ssl_verifyhost, 2);          // required if server missing global cert bundle, or using outdated one.         if ($this->use_local_certs) {             curl_setopt($ch, curlopt_cainfo, __dir__ . "/cert/cacert.pem");         }         curl_setopt($ch, curlopt_forbid_reuse, 1);         curl_setopt($ch, curlopt_connecttimeout, 30);         curl_setopt($ch, curlopt_httpheader, ['connection: close']);         $res = curl_exec($ch);         $info = curl_getinfo($ch);         $http_code = $info['http_code'];          if ($http_code != 200) {             throw new exception("paypal responded http code $http_code");         }          if ( ! ($res)) {             $errno = curl_errno($ch);             $errstr = curl_error($ch);             curl_close($ch);             throw new exception("curl error: [$errno] $errstr");         }         curl_close($ch);          // check if paypal verfifes ipn data, , if so, return true.         if ($res == self::valid) {             return true;         } else {             return false;         }     }    public function getpostdata(){         return $postdata;     } } 

usage:

<?php require('paypalipn.php');  echo "im in";  require_once 'login.php';  use paypalipn;  $ipn = new paypalipn();  // use sandbox endpoint during testing. $verified = $ipn->verifyipn(); if ($verified) {     /*      * process ipn      * list of variables available here:      * https://developer.paypal.com/webapps/developer/docs/classic/ipn/integration-guide/ipnandpdtvariables/      */     $conn = new mysqli($hn,$un,$pw,$db);     if ($conn->connect_error){         die($conn->connect_error);     }      $lastname = $ipn->getpostdata();     $name = "ipnname";     $email = "ipnemail";       $query = "insert testtable (lastname ,name ,email) values ('$lastname',  '$name',  '$email')";     $result = $conn->query($query);     if (!$result){         die ("query failed");     }   }  // reply empty 200 response indicate paypal ipn received correctly. header("http/1.1 200 ok");