微信授权

//微信授权
    public function getOpenid()
    {

        $openid = Session('openid');
        if (!$openid) {
            if (!isset($_GET['code'])) {
                $url = $this->getAuthorizeUrl();
                Header("Location: $url");
                exit();
            } else {
                $state = Session('state');
                if ($state == $_GET['state']) {

                    $code=$_GET['code'];

                    $token = $this->getAccessToken($code);
                    $access_token=$token['access_token'];
                    $open=$token['openid'];
                    $acctoken="https://api.weixin.qq.com/sns/userinfo?access_token=$access_token&openid=$open&lang=zh_CN";
                    $userinfo = $this->httpsRequest($acctoken);
                    $info = json_decode($userinfo, true);
                    $openid = isset($token['openid']) ? $token['openid'] : '';
                    if ($openid) {
                        Session("openid", $openid);
                    }
                }
            }
        }
        return $info;
    }
    public function getAuthorizeUrl()
    {
        $redirect_uri ="http://lk.a40.com.cn/api.php/api/login";

        $redirect_uri = urlencode($redirect_uri);

        $state =rand(1000,9999);
        Session('state', $state);
        return "https://open.weixin.qq.com/connect/oauth2/authorize?appid=wxe040024d0d8d6c1e&redirect_uri={$redirect_uri}&response_type=code&scope=snsapi_userinfo&state={$state}#wechat_redirect";
    }

    public function getAccessToken($code = '')
    {

        $ret ="https://api.weixin.qq.com/sns/oauth2/access_token?appid=wxe040024d0d8d6c1e&secret=4ce2185589f1a7e0906341d10f8f42b4&code=$code&grant_type=authorization_code";
        $token_info = $this->httpsRequest($ret);
        $token_info = json_decode($token_info, true);
       return  $token_info;
    }
    public function httpsRequest($url) {
        $curl = curl_init();
        curl_setopt($curl, CURLOPT_URL, $url);
        curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
        curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, FALSE);
        curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
        $output = curl_exec($curl);
        curl_close($curl);
        return $output;
    }