令牌token与代码token字段一直，域名访问用get

/**
     * 自定义方法，用于微信访问验证开发者身份
     *
     * @param Request $request
     * @return array|null|string
     */
    public function wxtoken(Request $request)
    {
        $signature = $request->input('signature');
        $timestamp = $request->input('timestamp');
        $nonce = $request->input('nonce');
        $echoStr = $request->input('echostr');
        if ($this->checkSignature($signature, $timestamp, $nonce)) {
            ob_end_clean(); //必须清空缓冲区
            return $echoStr;
        } else {
            return 'Token verification failed.';
        }
    }

    /**
     * 微信官方提供的验签方法
     *
     * @param $signature
     * @param $timestamp
     * @param $nonce
     * @return bool
     */
    private function checkSignature($signature, $timestamp, $nonce)
    {
        $token = 'token';
        $tmpArr = array($token, $timestamp, $nonce);
        sort($tmpArr, SORT_STRING);
        $tmpStr = implode($tmpArr);
        $tmpStr = sha1($tmpStr);

        if ($tmpStr == $signature) {
            return true;
        } else {
            return false;
        }
    }