易支付接口对接文档

pid          = 100001
type         = alipay
out_trade_no = MCH20260728001
notify_url   = https://shop.com/notify
return_url   = https://shop.com/return
name         = VIP会员
money        = 1.00
clientip     = 1.2.3.4
param        =                  ← 空值，剔除
key（密钥）  = a1b2c3d4e5f6g7h8i9j0k1l2m3n4o5p6

{
  "code": 1,
  "msg": "",
  "trade_no": "PN20260728120000123",
  "out_trade_no": "MCH20260728001",
  "money": "1.00",
  "payurl": "https://pay.example.com/xxxx"
}

GET https://shop.com/notify?money=1.00&name=VIP%E4%BC%9A%E5%91%98&out_trade_no=MCH20260728001
    &pid=100001&sign=xxxxxxxx&sign_type=MD5&trade_no=PN20260728120000123&trade_status=TRADE_SUCCESS

GET /api.php?act=order&pid=100001&key=你的密钥&out_trade_no=MCH20260728001

<?php
const GATEWAY = 'https://pay.example.com'; // 网关地址，开户后由官方客服提供
const PID     = '100001';
const KEY     = '你的商户密钥';

/** 生成签名：剔除空值与 sign/sign_type，按键名排序，拼接后追加密钥取 MD5 */
function epaySign(array $params, string $key): string {
    unset($params['sign'], $params['sign_type']);
    $params = array_filter($params, fn($v) => $v !== '' && $v !== null);
    ksort($params);
    $parts = [];
    foreach ($params as $k => $v) {
        $parts[] = "$k=$v"; // 注意：值不做 urlencode
    }
    return md5(implode('&', $parts) . $key);
}

/** 下单，返回支付地址 */
function epayCreate(array $biz): array {
    $params = array_merge($biz, ['pid' => PID]);
    $params['sign'] = epaySign($params, KEY);
    $params['sign_type'] = 'MD5';

    $ch = curl_init(GATEWAY . '/mapi.php');
    curl_setopt_array($ch, [
        CURLOPT_POST           => true,
        CURLOPT_POSTFIELDS     => http_build_query($params),
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_TIMEOUT        => 30,
    ]);
    $resp = curl_exec($ch);
    curl_close($ch);

    $data = json_decode($resp, true);
    if (!$data || ($data['code'] ?? -1) != 1) {
        throw new Exception('下单失败：' . ($data['msg'] ?? $resp));
    }
    // payurl / qrcode / urlscheme 三者只返回其一，都要兼容
    $data['pay_target'] = $data['payurl'] ?? $data['qrcode'] ?? $data['urlscheme'] ?? '';
    return $data;
}

// ---------- 下单 ----------
$order = epayCreate([
    'type'         => 'alipay',
    'out_trade_no' => 'MCH' . date('YmdHis'),
    'notify_url'   => 'https://shop.com/notify.php',
    'return_url'   => 'https://shop.com/return.php',
    'name'         => 'VIP会员',
    'money'        => '1.00',
    'clientip'     => $_SERVER['REMOTE_ADDR'],
]);
header('Location: ' . $order['pay_target']);

// ---------- 接收异步通知（notify.php） ----------
$params = $_GET; // 框架已自动 urldecode
if (epaySign($params, KEY) !== ($params['sign'] ?? '')) {
    exit('sign error'); // 验签失败，不可发货
}
if (($params['trade_status'] ?? '') !== 'TRADE_SUCCESS') {
    exit('success'); // 非成功状态，应答避免重试
}
// 幂等：同一订单号可能收到多次通知，必须保证只发货一次
if (!alreadyShipped($params['out_trade_no'])) {
    ship($params['out_trade_no'], $params['money']);
}
exit('success'); // 只输出 success，不要带 HTML