paypal更新（2018年9月）后，ecshop paypal支付无法更新支付状态

原因：原EC的请求方式获取到404错误，后经反复测试，发现是由于paypal更新了隐私策略，导致了请求的链接中含有不被paypal识别的字符，直接返回错误结果。

解决方法：改为POST方式请求接口。

支付文件代码如下（定制过的按需求修改）：

提示，该代码是老杨在LYECS版本测试通过后，再移植到原版ECSHOP中的，所以未经测试，具体思路大家自行根据自己的情况修改。代码仅供参考，老杨不提供技术支持。

<?php

if (!defined('IN_ECS'))
{
    die('Hacking attempt');
}

$payment_lang = ROOT_PATH . 'languages/' .$GLOBALS['_CFG']['lang']. '/payment/paypal.php';

if (file_exists($payment_lang))
{
    global $_LANG;

    include_once($payment_lang);
}

/* 模块的基本信息 */
if (isset($set_modules) && $set_modules == TRUE)
{
    $i = isset($modules) ? count($modules) : 0;

    /* 代码 */
    $modules[$i]['code']    = basename(__FILE__, '.php');

    /* 描述对应的语言项 */
    $modules[$i]['desc']    = 'paypal_desc';

    /* 是否支持货到付款 */
    $modules[$i]['is_cod']  = '0';

    /* 是否支持在线支付 */
    $modules[$i]['is_online']  = '1';

    /* 作者 */
    $modules[$i]['author']  = 'http://www.lyecs.com';

    /* 网址 */
    $modules[$i]['website'] = 'http://www.paypal.com';

    /* 版本号 */
    $modules[$i]['version'] = '1.0.0';

    /* 配置信息 */
    $modules[$i]['config'] = array(
        array('name' => 'paypal_account', 'type' => 'text', 'value' => ''),
        array('name' => 'paypal_currency', 'type' => 'select', 'value' => 'USD')
    );

    return;
}

/**
 * 类
 */
class paypal
{
    /**
     * 构造函数
     *
     * @access  public
     * @param
     *
     * @return void
     */
    function paypal()
    {
    }

    function __construct()
    {
        $this->paypal();
    }

    /**
     * 生成支付代码
     * @param   array   $order  订单信息
     * @param   array   $payment    支付方式信息
     */
    function get_code($order, $payment)
    {
        $data_order_id      = $order['log_id'];
        $data_amount        = $order['order_amount'];
        $data_return_url    = return_url(basename(__FILE__, '.php'));
        $data_pay_account   = $payment['paypal_account'];
        $currency_code      = $payment['paypal_currency'];
        $data_notify_url    = return_url(basename(__FILE__, '.php'));
        $cancel_return      = $GLOBALS['ecs']->url();

        $def_url  = '<br /><form style="text-align:center;" action="https://www.paypal.com/cgi-bin/webscr" method="post" target="_blank">' .   // 不能省略
            "<input type='hidden' name='cmd' value='_xclick'>" .                             // 不能省略
            "<input type='hidden' name='business' value='$data_pay_account'>" .                 // 贝宝帐号
            "<input type='hidden' name='item_name' value='$order[order_sn]'>" .                 // payment for
            "<input type='hidden' name='amount' value='$data_amount'>" .                        // 订单金额
            "<input type='hidden' name='currency_code' value='$currency_code'>" .            // 货币
            "<input type='hidden' name='return' value='$data_return_url'>" .                    // 付款后页面
            "<input type='hidden' name='invoice' value='$data_order_id'>" .                      // 订单号
            "<input type='hidden' name='charset' value='utf-8'>" .                              // 字符集
            "<input type='hidden' name='no_shipping' value='1'>" .                              // 不要求客户提供收货地址
            "<input type='hidden' name='no_note' value=''>" .                                  // 付款说明
            "<input type='hidden' name='notify_url' value='$data_notify_url'>" .
            "<input type='hidden' name='rm' value='2'>" .
            "<input type='hidden' name='cancel_return' value='$cancel_return'>" .
            "<input type='submit' value='" . $GLOBALS['_LANG']['paypal_button'] . "'>" .                      // 按钮
            "</form><br />";

        return $def_url;
    }

    /**
     * 响应操作
     */
    function respond()
    {
        $payment        = get_payment('paypal');
        $merchant_id    = $payment['paypal_account'];               ///获取商户编号

        // read the post from PayPal system and add 'cmd'
        // $req = 'cmd=_notify-validate';
        $_POST['cmd']='_notify-validate';
        // foreach ($_POST as $key => $value)
        // {
        //     $value = urlencode(stripslashes($value));
        //     $req .= "&$key=$value";
        // }

        // post back to PayPal system to validate
        $header = "POST /cgi-bin/webscr HTTP/1.0\r\n";
        $header .= "Content-Type: application/x-www-form-urlencoded\r\n";
        $header .= "Content-Length: " . strlen($req) ."\r\n\r\n";
        //$fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30);

        // 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'];
        $order_sn = $_POST['invoice'];
        $memo = !empty($_POST['memo']) ? $_POST['memo'] : '';
        $action_note = $txn_id . '（' . $GLOBALS['_LANG']['paypal_txn_id'] . '）' . $memo;
        if($req){
            $res=$this->send_paypal_url('https://www.paypal.com',$_POST);
        }
        if (strcmp($res, 'VERIFIED') == 0)
        {
            // check the payment_status is Completed
            if ($payment_status != 'Completed' && $payment_status != 'Pending')
            {

                return false;
            }

            // check that txn_id has not been previously processed
            /*$sql = "SELECT COUNT(*) FROM " . $GLOBALS['ecs']->table('order_action') . " WHERE action_note LIKE '" . mysql_like_quote($txn_id) . "%'";
            if ($GLOBALS['db']->getOne($sql) > 0)
            {

                return false;
            }*/

            // check that receiver_email is your Primary PayPal email
            if ($receiver_email != $merchant_id)
            {

                return false;
            }

            // check that payment_amount/payment_currency are correct
            $sql = "SELECT order_amount FROM " . $GLOBALS['ecs']->table('pay_log') . " WHERE log_id = '$order_sn'";
            if ($GLOBALS['db']->getOne($sql) != $payment_amount)
            {

                return false;
            }
            if ($payment['paypal_currency'] != $payment_currency)
            {

                return false;
            }

            // process payment
            order_paid($order_sn, PS_PAYED, $action_note);

            return true;
        }
        elseif (strcmp($res, 'INVALID') == 0)
        {
            // log for manual investigation

            return false;
        }
    }
    function send_paypal_url($url, $post_data = '', $timeout = 5){
        $options = array(
            CURLOPT_RETURNTRANSFER =>true,
            CURLOPT_HEADER =>false,
            CURLOPT_POST =>true,
            CURLOPT_POSTFIELDS => $post_data,
            );
        $ch = curl_init($url);
        curl_setopt_array($ch, $options);
        $result = curl_exec($ch);
        curl_close($ch);
        return $result;
    }
}

?>