微信小程序openid获取

先下载guzzle：

composer require "guzzlehttp/guzzle"="~6.0"

前端小程序 ：

    // 获取openID
    wx.login({
      success: (res) => {
         wx.request({
          url: 'http://www.cs.com/api/login/open',
          method: "GET",
          data: {
            code: res.code
          },
          success: (result) => {
            that.setData({
              openid: result.data.data
            })
          }
        })
      }
    })

PHP代码： 

 $code = $request->get("code");
        $appid =自己的appid;
        $secret =自己的secret;
        $url = "https://api.weixin.qq.com/sns/jscode2session?appid=$appid&secret=$secret&js_code=$code&grant_type=authorization_code";
        $client = new Client(["timeout" => 2.0, 'verify' => false]);
        $response = $client->get($url);
        $res = (string)$response->getBody();
        //$result是json类型，转为数组
        $result = json_decode($res, true);