微信支付V3

use GuzzleHttp\Client;

class WxPay
{
    private $appId = 'wxd3073***045a';
    private $mchId = '149***8522';
    private $notifyUrl = 'http://a.com';
    private $apiclientKey = '';
    private $client;
    private $serialNo = '5C758F2A5***DA29944CA4938';

    public function __construct()
    {
        $this->apiclientKey = file_get_contents('apiclient_key.pem');
        $this->client = new Client([
            'base_uri' => 'https://api.mch.weixin.qq.com',
            'timeout' => 5,
            'verify' => false,
            'http_errors' => false,
        ]);
    }

    public function getSign($data)
    {
        $str = implode("\n", array_merge($data, ['']));
        openssl_sign($str, $signature, $this->apiclientKey, OPENSSL_ALGO_SHA256);
        return base64_encode($signature);
    }

    // JSAPI下单 description,out_trade_no,amount,payer
    public function jsapi($param)
    {
        $method = 'POST';
        $api = '/v3/pay/transactions/jsapi';
        $timestamp = time();
        $nonce = uniqid();

        $data = array_merge($param, [
            'appid' => $this->appId,
            'mchid' => $this->mchId,
            'notify_url' => $this->notifyUrl,
        ]);

        $authorization = $this->getAuthorization($method, $api, json_encode($data));

        $r = $this->client->request($method, $api, [
            'headers' => [
                'Accept' => 'application/json',
                'Content-Type' => 'application/json',
                'Authorization' => $authorization,
            ],
            'json' => $data
        ]);

        $res = json_decode($r->getBody()->getContents(), 1);
        if (!isset($res['prepay_id'])) return $res;

        $package = 'prepay_id=' . $res['prepay_id'];
        $paySign = $this->getSign([$this->appId, $timestamp, $nonce, $package]);

        return [
            'appId' => $this->appId,
            'timeStamp' => $timestamp,
            'nonceStr' => $nonce,
            'package' => $package,
            'signType' => 'RSA',
            'paySign' => $paySign,
        ];
    }

    // 商户订单号查询订单
    public function findOrder($orderNo)
    {
        $method = 'GET';
        $api = "/v3/pay/transactions/out-trade-no/{$orderNo}?mchid={$this->mchId}";
        $authorization = $this->getAuthorization($method, $api);

        $r = $this->client->request($method, $api, [
            'headers' => [
                'Accept' => 'application/json',
                'Authorization' => $authorization,
            ]
        ]);

        return $r->getBody()->getContents();
    }

    public function getAuthorization($method, $api, $body = '')
    {
        $timestamp = time();
        $nonce = uniqid();
        $signature = $this->getSign([$method, $api, $timestamp, $nonce, $body]);
        $authorization = sprintf(
            'WECHATPAY2-SHA256-RSA2048 mchid="%s",serial_no="%s",timestamp="%s",nonce_str="%s",signature="%s"',
            $this->mchId, $this->serialNo, $timestamp, $nonce, $signature
        );

        return $authorization;
    }
}