PHP 개발: WeChat 결제 기능 구현 방법

define('MCH_ID', '商户号');
define('APPID', '应用ID');
define('KEY', 'API密钥');
define('CERT_PATH', '证书路径');

function createOrder($body, $out_trade_no, $total_fee, $notify_url) {
    $params = array(
        'appid' => APPID,
        'mch_id' => MCH_ID,
        'nonce_str' => uniqid(),
        'body' => $body,
        'out_trade_no' => $out_trade_no,
        'total_fee' => $total_fee,
        'spbill_create_ip' => $_SERVER['REMOTE_ADDR'],
        'notify_url' => $notify_url,
        'trade_type' => 'APP'
    );

    $params['sign'] = generateSign($params);

    $xml = arrayToXml($params);

    $response = sendRequest('https://api.mch.weixin.qq.com/pay/unifiedorder', $xml);

    $result = xmlToArray($response);

    return $result;
}

function generateSign($params) {
    ksort($params);

    $string = '';
    foreach ($params as $key => $value) {
        if ($key != 'sign' && $value != '') {
            $string .= "{$key}={$value}&";
        }
    }

    $string .= "key=" . KEY;

    return strtoupper(md5($string));
}

function arrayToXml($array) {
    $xml = "<xml>";
    foreach ($array as $key => $value) {
        $xml .= "<{$key}><![CDATA[{$value}]]></{$key}>";
    }
    $xml .= "</xml>";

    return $xml;
}

function sendRequest($url, $data) {
    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_POST, true);
    curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
    curl_setopt($ch, CURLOPT_SSLCERTTYPE, 'PEM');
    curl_setopt($ch, CURLOPT_SSLCERT, CERT_PATH);
    curl_setopt($ch, CURLOPT_SSLKEYTYPE, 'PEM');
    curl_setopt($ch, CURLOPT_SSLKEY, CERT_PATH);
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

    $response = curl_exec($ch);
    curl_close($ch);

    return $response;
}

$xml = file_get_contents("php://input");
$data = xmlToArray($xml);

if (isset($data['result_code']) && $data['result_code'] == 'SUCCESS') {
    // 支付成功，更新订单状态等操作
    // ...

    $response = array(
        'return_code' => 'SUCCESS',
        'return_msg' => 'OK'
    );
} else {
    // 支付失败，记录错误日志等操作
    // ...

    $response = array(
        'return_code' => 'FAIL',
        'return_msg' => 'ERROR'
    );
}

$responseXml = arrayToXml($response);
echo $responseXml;