lw_test/app/common.php

<?php
// 应用公共文件

function ajax_return($code = 0, $msg = '', $data = [])
{
    $res      = ['code' => $code, 'msg' => $msg, 'data' => $data];
    $response = \think\Response::create($res, 'json');
    throw new \think\exception\HttpResponseException($response);
}

function url(string $url = '', array $vars = [], $suffix = true, $domain = true)
{
    return \think\facade\Route::buildUrl($url, $vars)->suffix($suffix)->domain($domain);
}

function rand_str($len = 6)
{
    $str = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
    $res = '';
    for ($i = 0; $i < $len; $i++) {
        $key = rand(0, strlen($str));
        $res .= $str[$key];
    }
    return $res;
}