微信网页扫码登录

var $appid =‘*********‘;
    var $appsecret =‘**********‘;

    //构造函数，获取Access Token
    public function __construct($appid = NULL, $appsecret = NULL){
        parent::__construct();

        //扫码登录不需要该Access Token, 语义理解需要
        //1. 本地写入
        $res = file_get_contents(‘access_token.json‘);
        $result = json_decode($res, true);
        $this->expires_time = $result["expires_time"];
        $this->access_token = $result["access_token"];

        if (time() > ($this->expires_time + 3600)) {
            $url = "https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=" . $this->appid . "&secret=" . $this->appsecret;
            $res = getHttpJson($url);
            $result = json_decode($res, true);
            $this->access_token = $result["access_token"];
            $this->expires_time = time();
            file_put_contents(‘access_token.json‘, ‘{"access_token": "‘ . $this->access_token . ‘", "expires_time": ‘ . $this->expires_time . ‘}‘);
        }
    }

    /*
    *  PART1 网站应用
    */

    //生成扫码登录的URL
    public function qrconnect($redirect_url, $scope, $state = NULL)
    {
        $url = "https://open.weixin.qq.com/connect/qrconnect?appid=" . $this->appid . "&redirect_uri=" . urlencode($redirect_url) . "&response_type=code&scope=" . $scope . "&state=" . $state . "#wechat_redirect";
        return $url;
    }

    //生成OAuth2的Access Token
    public function oauth2_access_token($code)
    {
        $url = "https://api.weixin.qq.com/sns/oauth2/access_token?appid=" . $this->appid . "&secret=" . $this->appsecret . "&code=" . $code . "&grant_type=authorization_code";
        $res = getHttpJson($url);
        return $res;
    }

    //获取用户基本信息（OAuth2 授权的 Access Token 获取 未关注用户，Access Token为临时获取）
    public function oauth2_get_user_info($access_token, $openid)
    {
        $url = "https://api.weixin.qq.com/sns/userinfo?access_token=" . $access_token . "&openid=" . $openid . "&lang=zh_CN";
        $res = getHttpJson($url);
      // return json_decode($res, true);
        return $res;
    }

    public function wx_login(){
        if (!isset($_GET["code"])){

            $redirect_url = ‘http://‘.$_SERVER[‘HTTP_HOST‘].$_SERVER[‘REQUEST_URI‘];
            //  $redirect_url = ‘http://www.gizone.net‘.$_SERVER[‘REQUEST_URI‘];

            $jumpurl = $this->qrconnect($redirect_url, "snsapi_login", "123");

            Header("Location: $jumpurl");
        }else{
            $oauth2_info = $this->oauth2_access_token($_GET["code"]);

           // $userinfo = $this->oauth2_get_user_info($oauth2_info[‘access_token‘], $oauth2_info[‘openid‘]);
            $user=M(‘wx_user‘)->where(array(‘unionid‘=>$oauth2_info[‘unionid‘]))->find();
            $username=M(‘person‘)->where(array(‘uid‘=>$user[‘uid‘]))->find()[‘ps_name‘];
            $user_list=M(‘user‘)->where(array(‘uid‘=>$user[‘uid‘]))->find();

            if(!empty($user[‘uid‘])){  //有unionid且是已绑定用户可以登录
                session("username", $username);
                session("uid", $user["uid"]);
                session("user", $user_list);
                $this->success(‘登录成功‘, U(‘Index/index‘));

            }else{  //没有unionid且不为已绑定用户不能登录
                $this->error(‘您没有登录权限‘,U(‘Public/login‘));
            }

        }

    }

原文地址：https://www.cnblogs.com/zrn-php/p/9448026.html