<?php

$environment = 'sandbox';   // or 'beta-sandbox' or 'live'

/**
 * Send HTTP POST Request
 *
 * @param   string  The API method name
 * @param   string  The POST Message fields in &name=value pair format
 * @return  array   Parsed HTTP Response body
 */
function PPHttpPost($methodName_, $nvpStr_) {
    global $environment;

    $API_UserName = urlencode('my_api_username');
    $API_Password = urlencode('my_api_password');
    $API_Signature = urlencode('my_api_signature');
    $API_Endpoint = "https://api-3t.paypal.com/nvp";
    if("sandbox" === $environment || "beta-sandbox" === $environment) {
        $API_Endpoint = "https://api-3t.$environment.paypal.com/nvp";
    }
    $version = urlencode('51.0');

    // setting the curl parameters.
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $API_Endpoint);
    curl_setopt($ch, CURLOPT_VERBOSE, 1);

    // turning off the server and peer verification(TrustManager Concept).
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, FALSE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, FALSE);

    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_POST, 1);

    // NVPRequest for submitting to server
    $nvpreq = "METHOD=$methodName_&VERSION=$version&PWD=$API_Password&USER=$API_UserName&SIGNATURE=$API_Signature$nvpStr_";

    // setting the nvpreq as POST FIELD to curl
    curl_setopt($ch, CURLOPT_POSTFIELDS, $nvpreq);

    // getting response from server
    $httpResponse = curl_exec($ch);

    if(!$httpResponse) {
        exit("$methodName_ failed: ".curl_error($ch).'('.curl_errno($ch).')');
    }

    // Extract the RefundTransaction response details
    $httpResponseAr = explode("&", $httpResponse);

    $httpParsedResponseAr = array();
    foreach ($httpResponseAr as $i => $value) {
        $tmpAr = explode("=", $value);
        if(sizeof($tmpAr) > 1) {
            $httpParsedResponseAr[$tmpAr[0]] = $tmpAr[1];
        }
    }

    if((0 == sizeof($httpParsedResponseAr)) || !array_key_exists('ACK', $httpParsedResponseAr)) {
        exit("Invalid HTTP Response for POST request($nvpreq) to $API_Endpoint.");
    }

    return $httpParsedResponseAr;
}

$nvpStr="";

$httpParsedResponseAr = PPHttpPost('GetBalance', $nvpStr);

if("SUCCESS" == strtoupper($httpParsedResponseAr["ACK"]) || "SUCCESSWITHWARNING" == strtoupper($httpParsedResponseAr["ACK"])) {
    exit('GetBalance Completed Successfully: '.print_r($httpParsedResponseAr, true));
} else  {
    exit('GetBalance failed: ' . print_r($httpParsedResponseAr, true));
}

?>